[Quanfeng Biology] Application of plant growth regulator in fruit tree -- strawberry

Section I Propagation of virus-free seedlings1. Strawberry virus-free seedlingsStrawberry virus-free seedlings are those that have completely removed strawberry virus. Strawberry virus disease is a disease caused by strawberry infection, which shows two symptom types in cultivation: yellowing type and shrinking leaf type. Strawberry virus disease has a wide range of hazards. According to incomplete statistics, there are as many as 62 kinds of strawberry disease viruses, among which Strawberry mottle virus (SmoV), Strawberry mild yellow edge virus (SMTEV), Strawberry vein-band virus (SVBV) and Strawberry crinkle virus (sCrV) are four main viruses infecting strawberries in China, with a total infection rate of 80.2%, The infection rate of single virus is 41.6%, and the combined infection rate of two or more viruses is 38.6% (Ma Chongjian, 2004). Strawberries infected with virus disease grow slowly, their leaves shrink, their fruits become smaller, deformed, and their quality decreases year by year. At present, there is no medicine to control the virus disease. The use of virus-free cultivation seedlings such as strawberry stem tip is an effective way to control the virus disease, improve the quality of strawberry and improve the yield of strawberry. Strawberry virus-free seedlings have the characteristics of fast growth, vigorous growth, thick stems and leaves, strong resistance to disease, high temperature and cold, many flowers, high fruit setting rate, large fruit, neat and uniform, bright color, no abnormal fruit, high yield and good economic benefits, and are generally welcomed by fruit farmers. However, virus-free strawberry seedlings will be re-infected with the virus under field production conditions, and the infection rate is generally 10%~20% per year. Therefore, the majority of fruit farmers can continue to ensure high economic benefits by replacing the virus-free seedlings after 2 to 3 years of application.Qin Lanying et al. (1988) showed that stem tip culture had different degrees of virus removal. The smaller the stem tip, the greater the chance of virus removal. The higher the virus removal rate of the stem tip below 0.3 mm, and the tissue culture seedlings did not carry virus; Only 20% of the stems above 0.5mm were virus-free. After heat treatment, the effect of virus-free was significantly increased by taking stem meristem for culture, which was proved to be more reliable by electron microscope observation.The stem tip tissue culture of strawberry virus-free seedlings goes through the steps of explant selection, induction culture, proliferation culture, rooting culture, etc. Generally, from June to August, select middle-aged, disease-free, pure and healthy plants with fine weather, and cut 2~3cm stolon segments with growth points from the new shoots as explants, and wash them with running water. Place the surface cleaned explants on the ultra-clean workbench, disinfect the surface with 70% ethanol for 1 minute, discard the ethanol, add 0.1% mercuric chloride and 1 drop of Tween-20 to disinfect for 8 to 10 minutes, and shake it constantly, then wash it with sterile water for 5 to 8 times, use sterile filter paper to absorb the water, remove the scales, and use the scalpel to pick up 0.2 to 0.3 mm of the stem tip under the dissecting microscope, and inoculate it in the stem tip induction medium. Stem tip culture conditions: daytime temperature 25 ℃ soil 2 ℃, light intensity 30~60 umol/(m2. s); The temperature at night is 18 ℃, the soil temperature is 2 ℃, the culture is dark, and the daily illumination is 12-16 hours. After induction and culture for 2 to 3 months, when the cluster adventitious buds are 1.5 to 2.0 cm, the test-tube plantlets that have passed the virus test are inoculated on the proliferation medium for multiplication. The multiplication culture is subcultured every 20 to 30 days (the total number of subcultures is not more than 8), and the seedlings with a height of 2 to 3 cm are selected to be transferred to the rooting medium for rooting culture. After 20~30 days of induced rooting culture, tissue culture seedlings of complete plants can be formed.2. Application of growth regulators in strawberry virus-free seedling propagationIn the process of stem tip tissue induction culture and proliferation culture, growth regulators have significant effects on improving shoot tip germination rate, subculture proliferation and promoting rooting.(1) Paclobutrazol: In strawberry tissue culture, with the increase of differentiation times and subculture times, the test-tube seedlings degenerated. Such as petiole thinning, leaf yellowing, and reduced differentiation rate. In addition, the survival rate of transplanting is one of the key factors for the success of rapid propagation of strawberry virus-free seedlings, and the survival rate of transplanting of test-tube seedlings is directly related to the rooting of test-tube seedlings. In the rooting stage, the plantlets with thin and weak yellowing have poor rooting effect, and the survival rate is low after the bottle is out. At present, the application of paclobutrazol in strawberry tissue culture has solved this problem well.Zhang Xitai et al. (1997) used strawberry tube seedlings that have been subcultured for five times and have grown thin, thin and yellow as the test material, added 0.2~1.0mg/L15% paclobutrazol and 0.25mg/L6-BA to MS medium for subculture, and added 0.2~0.8mg/L15% paclobutrazol and 0.2mg/L6-BA for rooting culture. The results showed that paclobutrazol had obvious dwarfing effect on strawberry tube seedlings in subculture. With the increase of the concentration of paclobutrazol, the rhizome of the plantlets regenerated from the test-tube plantlets gradually became thick, the petiole was short and thick, the leaves were thick, and the chlorophyll content was high. Compared with the control, the rhizome thickness increased by 31.6%~174.4%, the petiole length shortened by 7.3%~71.0%, and the differentiation multiple increased by 14.3%~221.4%. When the concentration of paclobutrazol was increased to 0.6mg/L, the differentiation times of plantlets in vitro began to decline. In strawberry rooting culture, paclobutrazol and 6-BA significantly promoted the root system growth of test-tube seedlings. Compared with the control, the number of roots increased by 24.3%~543.0%, and the effect of adding 0.4mg/L15% paclobutrazol and 0.2mg/L6-BA to 1/2MS medium was better.According to Ruan Long et al. (2002), adding 0.2~0.6mg/L paclobutrazol to 1/2MS Fengxiang strawberry virus-free seedling rooting medium can promote the increase of rooting number, root thickening and growth of strawberry virus-free seedlings. Compared with the rooting medium without paclobutrazol, the rooting number of Fengxiang test-tube seedlings increased by 10.9~15.7, the root diameter increased by 0.24~0.39 mm, and the root length increased by 0.27~0.70 cm, among which the treatment effect of adding 0.4mg/L paclobutrazol was better.Section II Regulate the growth of stolon and promote the elongation of the top inflorescence1. Strawberry stolon and top inflorescence growthStrawberry stolon is a vegetative reproductive organ on the ground of strawberry, which is sprouted from the axillary buds of new stems. Generally, in the late fruit setting and after harvest, the sunlight in early summer is enhanced, the temperature is increased, and the stolons sprout from the dormant axillary buds formed last autumn. A bract and axillary bud are formed on the first node of the stolon, and the axillary bud remains dormant. The growth point on the second node differentiates the leaf primordium. When 2 to 3 leaves are exposed, adventitious roots are produced, which are embedded in the soil, forming a first-level stolon seedling. At the same time as the first stage stolon seedlings are pregnant and differentiated, the axillary buds between the leaf axils produce new meristematic stolons. The axillary buds on the first node also remain dormant, and the growth points on the second node continue to differentiate leaf primordia. According to this rule, the stolon forms the 1st, 2nd, 3rd and 4th level stolon seedlings and meristematic stolon seedlings on the 2nd, 4th, 6th and 8th even-numbered nodes, and carries out multi-level network meristematic, resulting in a large number of stolon seedlings. The closer these stolons are to the mother plant, the better they will grow. Most of their top buds can form flower buds in the current year and blossom and bear fruit in the next year.Using stolons is a common method of seedling propagation in strawberry production. The number of stolons varies with varieties. Some varieties can sprout stolons many times in a year, and the number of stolons is more, while some varieties are not. Generally, cold varieties with high demand for low temperature, such as All-Star, Hani, etc., have less stolons; The varieties of warm ground that require short low temperature period, such as Baojiao Zaosheng, Fengxiang, Nufeng, etc., have more stolons.At present, strawberries are cultivated in plastic greenhouse in Jiangnan area. Due to the lack of heating equipment in the plastic greenhouse and the low temperature in winter, the growth of the top inflorescence is shorter, and the fruit shrinks under the plant. In addition, the poor ventilation and light transmission conditions in the greenhouse are easy to cause rotten fruit and cause economic losses. In order to promote the elongation of the top inflorescence of strawberry, make the fruit hang at the edge of the ditch, and reduce the rotten fruit, gibberellin was applied in production to promote the elongation of the top inflorescence, which has obvious effect.2. Regulation measures for the growth of stolon and inflorescence of grape(1) Promote stolon growth:In order to promote the occurrence of strawberry stolons, especially for varieties with few stolons, gibberellin can be sprayed. The method is to spray 50 mg/L gibberellin 1 to 2 times after the mother plant survives and grows three new leaves, and spray 5 to 10 mL per plant, which can effectively promote the occurrence of strawberry stolons and expand the propagation coefficient of seedlings.Yu Gengxu et al; The total number of secondary stolons was 18.7, which was 59.8% higher than that of water control; The secondary stolon occurred one week earlier than the control. In addition, GA3 can also relieve the inhibition of PP333 on strawberry, increase the number of stolons and petiole length of plants treated with PP333, and eliminate the inhibition of axillary bud development, but has no sustained effect on plant growth (Yang Huirong et al., 1993).(2) Inhibition of stolon growth:① PP333 sprayed with 250mg/L PP333 has obvious inhibitory effect on the length of stolon, plant height and petiole length of strawberry, and has an effect on increasing the yield of strawberry. It is worth noting that the inhibition effect of PP333 is too large. For example, after spraying with 500mg/L PP333 solution, it not only has extremely strong inhibitory effect on strawberry, but also can cause yield reduction. At the same time, until the fruit development period in May of the next year, there was still a large inhibitory effect, and the photosynthetic area was seriously reduced. Gibberellin has the effect of relieving the inhibition of paclobutrazol on strawberry. After spraying 20mg/L gibberellin solution on the leaves, it can take effect in about a week. After treatment with gibberellin, the strawberry seriously inhibited by paclobutrazol for a long time, the plant height was significantly increased, the petiole length was also significantly increased, and the growth potential was strengthened.(3) Promote terminal inflorescence elongationZhou Huayue (1997) experiment showed that after planting in the middle of September in the Fengxiang strawberry garden cultivated in the protected area, spraying 10mg/kg gibberellin once at the beginning of the bud emergence of the top inflorescence, and spraying once again 10 days after spraying, a total of two times, can significantly promote the elongation of the top inflorescence of Fengxiang strawberry, mature early, improve the early yield, and reduce rotten fruit. Compared with the control, the average length of the top inflorescence increased by 7.9 cm, the initial harvest date of fresh fruit was 13 days earlier, and the weight of fresh strawberry fruit in the early stage before the end of February increased by 44.6%. The number of fresh and rotten strawberries in the early stage (before the end of February) was only 8.5% of the control, with significant economic benefits.Section 3 Break dormancy and promote flower bud differentiation1. Strawberry dormancy and flowering physiologyAfter the flower bud differentiation of strawberry, under the conditions of lower temperature and shorter sunshine in late autumn and early winter, the plant enters into dormancy, with dwarfing morphology, small new leaves and short petioles. Although there are flowers and fruits, there are no stolons. The dormancy period of strawberry starts from a period of time after flower bud differentiation and gradually deepens, and generally reaches a deeper dormancy period in the middle and late November. After dormancy, different varieties need to experience different low temperature hours to break dormancy. The northern varieties have deep dormancy and need a long time of low temperature; the southern varieties have shallow dormancy or no dormancy and need a few hours of low temperature. Too many low temperature hours will lead to vigorous growth. Too many stolons occur and the result is bad. Varieties with low demand for low temperature are suitable for facilitating cultivation, and vice versa are suitable for semi-facilitating or open field cultivation. Long sunshine, high temperature or spraying gibberellin can break its dormancy. The above treatment can prevent it from entering dormancy and continue to blossom and bear fruit when it is about to enter dormancy; In the late stage of dormancy, the dormancy can be broken early and the growth can be resumed in flowering and fruiting.Strawberry is a short-day plant. Low temperature and short-day can induce strawberry to flower. Under natural conditions, strawberry can induce flower bud differentiation under night temperature of about 17 ℃ and sunshine of less than 12 hours, and flower bud can be formed after 9~16 days. Many studies have been done on the effect of hormones on strawberry flowering, among which there are many studies supporting the theory of "flowering inhibitory substances". The research results of Thompson and Guttridge showed that the higher the concentration of gibberellin, the longer the stem and petiole, the greater the occurrence of stolon, and the deeper the inhibition of flowering process. The effect was similar to that of long sunshine treatment. Ballinger et al. also proved the existence of gibberellin at the top of stolon and crown, and the gibberellin substances decreased at the stage of flower bud differentiation, and began to increase after the elongation of flower stalk. Hou Zhixia et al. (2004) believed that spraying gibberellin when some plants began to differentiate flower buds, while the other plants did not differentiate, and destroying the short sunshine conditions suitable for strawberry flower formation, could reverse the meristem of strawberry stem tip, return to the vegetative growth state, and could not form flower buds; Before that, when gibberellin was sprayed, the growth point could not turn into flowers, and flower buds could not form. The higher the concentration of gibberellin, the deeper the inhibition.2. Technical measures to break dormancy and promote flower bud differentiationAt present, gibberellin is used in strawberry production to release dormancy, promote development, increase yield and promote stolon occurrence. When gibberellin is used to treat strawberry to promote flower bud differentiation, the treatment period must be well controlled. It is better to treat strawberry at the beginning of growth point hypertrophy, which has no effect too early, and has side effects too late. Generally, the suitable period for treatment is from the germination of new buds to the development of flower buds. If it is too late or the temperature after treatment is too high, the rate of abnormal fruit will be high.Lu Junxia et al. In addition, spraying 50mg/L gibberellin when the growth point is fat at the early stage of flower bud differentiation can make Futian blossom one week earlier; If it is treated in advance, it will not have this effect, but after treatment, it will produce deformed fruit, or make the fruit stem excessively elongate. Shen Xiaoli et al. (1996) showed that the best time to inhibit strawberry dormancy and promote flowering was after the flower bud differentiation of the second and third order flowers when using gibberellin to promote early ripening of strawberry. Generally, the strawberry is sprayed from the end of October to the beginning of November, with a better concentration of 10mg/L, which can make the strawberry maintain a better plant height of about 20cm at the beginning of harvest, and the harvest period is 20 to 30 days ahead of schedule, and the yield and quality are in a better state.According to the investigation conducted by Wang Zhonghe (2007) in Shandong, ① in the semi-accelerated cultivation of strawberry, spraying 8~10mg L gibberellin at the early stage of growth has the effect of long sunshine, which can promote the development of flower buds and make the first inflorescence blossom early; It can promote the elongation of petiole and increase the three-dimensional photosynthetic space; It can promote the elongation of flower stalks and facilitate pollination and fruit development. ② In the accelerated cultivation of strawberry, early heat preservation and gibberellin treatment have the effect of inhibiting dormancy, and generally spray gibberellin 5~10mg/L for 1~2 times after the beginning of heat preservation. Spraying for the first time at the stage of 2 undeveloped leaves can promote the growth of young leaves and prevent dormancy; Spraying twice at the bud stage can promote the elongation of flower stalks and facilitate pollination and fertilization. When applying gibberellin on strawberries, we must pay attention to: the concentration should not be too high, the dosage should not be too large, 3~5mL per plant is enough, and the wine should be sprayed on the heart of the seedlings; The concentration varies with the variety. The varieties with shallow dormancy use less than those with deep dormancy, and the cold ground uses less than those with warm ground, and the number of times is also less. The varieties with deep dormancy, such as Dukara and Baojiao Zaosheng, can use 10mg

Planting technology and management of wheat

Classification of wheat varieties: according to different sowing seasons, wheat can be divided into spring wheat and winter wheat. According to the different color of wheat grain, wheat can be divided into red wheat and white wheat, which are called red wheat and white wheat for short. According to the different grain quality, wheat can be divided into hard wheat and soft wheat, which are called hard wheat and soft wheat for short.The Life of Wheat（1） During the growth period, wheat undergoes a series of growth and development processes from seed germination, seedling emergence, rooting, leaf growth, jointing, booting, heading, flowering, and seed setting to the generation of new seeds, which is called the life of wheat. The number of days required from sowing to maturity is called the growth period. The growth period of wheat is generally 190~210 days.（2） According to the growth characteristics of wheat at different stages, in order to facilitate cultivation and management, the life of wheat can be divided into 12 growth periods, namely, seedling emergence, trefoil, tillering, overwintering, turning green, rising, jointing, booting, heading, flowering, filling and maturity.（3） According to the characteristics of wheat organ formation, several continuous growth stages can be combined into a certain growth stage. Generally, it can be divided into three growth stages.1. The seedling stage is from emergence to start. It mainly carries out vegetative growth, that is, long roots, long leaves and tillers.2. The middle stage is from the start to the flowering stage. This is a stage in which vegetative growth and reproductive growth go hand in hand. There are root, stem and seasonal growth, as well as ear differentiation and development.3. The later stage is from flowering to maturity. Also known as grain formation stage, it is mainly reproductive growth.Soil, water, nutrients, temperature, light and air are the necessary environmental conditions for wheat growth and development. To achieve high yield of wheat, on the one hand, we should select excellent varieties according to local conditions, on the other hand, we should create environmental conditions suitable for wheat growth and development through field management.1. Land selection and preparation is the basisSoil fertility is the basis for achieving high yield of wheat. Only by selecting an environment with good soil fertility and sufficient topsoil thickness can high-quality wheat be planted. At the same time, when selecting the land, it is necessary to clean the previous stubble, and then plough deeply in time, so as to make sure that the top is empty and the bottom is solid, so as to facilitate the seed germination and root stability. If necessary, certain drugs can be added in deep ploughing to prevent pests in advance.2. Seed selectionSeed is the main factor to increase yield, and improved seed is the internal cause of yield increase, and is the basis for the development of agricultural science and technology. In the selection of seeds, we must combine the local soil conditions, select seeds with high yield, stability, quality, lodging resistance and high productivity, and pay attention to varieties with good economic benefits and early maturity.Before sowing, we should choose a good weather for about a week to sun the seeds, which can not only prevent mold and insects, but also improve the germination rate and promote the yield. Air drying once a month and 10 days before sowing will reduce the rate of insect erosion and increase the germination rate.In addition, seed dressing is also necessary. Seed dressing is the measure of mixing fertilizer, pesticide and wheat seeds in a certain proportion, and then mixing them repeatedly to make the fertilizer and pesticide evenly adhere to the surface of the seeds. The amount of seed mixing is small, the operation is simple, and the effect is good. For diseases and insect pests transmitted by seeds, seed dressing has almost become the only control measure, which not only eliminates the seed carrier, but also protects the seedlings from infection.3. Seeding managementAccording to the specific local conditions, select a better farming mode. According to the specific situation of the year, sow in time at the sowing time, and select a better sowing amount according to the soil and weather conditions. Generally, due to the poor soil conditions in the middle field, the planting amount can be appropriately increased, and the goal of increasing yield can be achieved by increasing the number of main stems and ears as much as possible. If it is a high-yield field, it is unnecessary, as long as it is carried out according to the normal seeding rate. If it is too much, it will easily reduce the permeability, reduce the individual growth ability, and then lead to lodging and reduce the yield. In a word, the amount of seeding is the key to establish a reasonable population structure. There must be certain differences in seeding amount with different varieties. The depth of 3-4 cm is better. Such seeding can ensure the seedlings are neat and strong, and then promote the yield and achieve the purpose of increasing income.4. Strengthen field managementFirst of all, from seedling emergence to tillering, wheat mainly grows leaves, roots and tillers. After seedling emergence, seedlings should be thinned at the first time to improve the uniformity of seedlings. If the weather is too dry, water it in time to ensure that the wheat can take root at the first time, tiller in time, improve the growth ability of the seedlings and strengthen the cold resistance of the wheat. For the wheat field with weak growth, the tillering fertilizer should be applied in time during the overwintering period. Generally, urea is the main fertilizer. If the fertilizer is not applied in time, the fertilizer should be applied in time in the next spring to promote rooting and tillering.The amount of water for winter irrigation of wheat should not be too large. It is better to be able to water thoroughly and completely on the same day. Generally, 30-40 cubic meters of water are irrigated per mu. In order to save water, it is necessary to complete the ditch and border to prevent flooding. After winter irrigation, timely hoe and loosen the soil to close the cracks, so as to maintain moisture and increase temperature.Prevention and control of dead wheat seedlings in winter: remove dead leaves and increase photosynthesis; Topdressing nitrogen fertilizer to promote rejuvenation; Water timely according to local conditions; Foliar fertilization to supplement nutrition; Cultivate and hoe, increase temperature and keep moisture.Secondly, when it comes to the jointing stage and the late growth stage of wheat, nitrogen fertilizer should be applied again. If the weather is dry, irrigation and fertilization should be combined to achieve better results. However, if the planting area is large and the seedling condition is relatively prosperous, it is necessary to delay the application of fertilizer to the late jointing stage, but it is necessary to reduce the amount of fertilizer properly. At the same time, for some fields with relatively good terrain, some herbicides should be added appropriately to remove weeds in time, so as to ensure the nutrition of wheat seedlings and promote the improvement of yield.The heading and flowering period of wheat is the key period for the formation of wheat yield and the peak period for the occurrence of diseases and insect pests. During this period, attention should be paid to the prevention and control of diseases and insect pests such as scab, stripe rust, powdery mildew, aphid, etc., to reduce the damage of plant diseases and insect pests, and lay a foundation for the later high yield of wheat.The head blight harms the ear of wheat: it causes the half-cut and withered ear of wheat, and the ear of wheat turns red when the field humidity is high; It is recommended to use triadimefon · tebuconazole, cyanoxylate, cyanene · hexazol and other chemicals for prevention and control.Thirdly, when the wheat grows to the filling stage, it can be sprayed with 1% - 2% urea solution. If the phosphorus and potassium elements in the soil are insufficient, 0.2% - 0.3% potassium dihydrogen phosphate solution can be appropriately increased to ensure the demand of plants for trace elements.Later, in the later stage of management, the main concern is the weeds in the field. Many weeds can not reach the goal through manual removal. Therefore, the grower should analyze the factors such as the type of weeds in the wheat field and select a better herbicide. The weeds in the wheat field are mainly monocotyledonous gramineae. For this kind of weeds, the main herbicides can be used, such as pygmalion, chlorpyrifos and isoproturon. For some plots with relatively more weeds, butachlor and trifluralin can be mixed and sprayed; If there are many broad-leaved grass in the plot, use good to eliminate it. In addition to the selection of herbicides, attention must also be paid to the humidity of the environment when using herbicides. Generally, it is better to keep the temperature above 10 ℃ after water. Try to spray when the seedlings are relatively small, so as to achieve the purpose of weeding, improve the cleanness of the wheat field, and promote the yield.5. Management of harvest period(1) Water the wheat straw wellAfter the waxy ripening of wheat, proper water supply can prolong the life of functional leaves, strengthen the accumulation and operation of photosynthetic products, especially in the rainy years, it is more important to water the wheat yellow water well, which can not only prevent the dry heat wind damage in the later period, but also promote the 1000-grain weight. According to the survey structure, the yield can be increased by about 10% by watering the wheat yellow water. Generally, watering the wheat yellow water after the wheat falls yellow can prevent late ripening. At this stage, the head of wheat spike is heavy, but we must pay attention to the weather conditions. If we encounter strong wind after watering, we can easily fall down. We must ensure that there is no strong wind in a day, and at the same time, we must control the amount of watering, not too much.(2) Grasp the exact harvest dateThe harvest season is when the wheat enters the late stage of waxy ripening. At this time, the wheat color turns yellow, the stem is elastic, the grain moisture content is also high, and the hardness is good and shiny. Another key step is to remove impurities. Only after removing impurities can the wheat reach a certain purity and achieve real high yield.

Planting technology and management of maize

Maize, the largest grain crop in China, is a kind of C4 plant in the biological range, but its bracts use C3 mode for photosynthesis. It is monoecious, and its main production area is located in the world's third largest corn belt - the Songliao Plain corn belt in China. The total planting area of maize is about 1249.35 square kilometers, also known as maize, corn (corn cob), corn, and stick. It is called millet in Cantonese and parva in Minnan. It is an annual grass herb, an important food crop and an important feed source, and also a food crop with a high total yield in the world.1、 Type of cornCorn is mainly divided into spring corn and autumn corn according to planting season. It can be divided into common corn, sweet corn, waxy corn, bamboo shoot corn, high-oil corn and popcorn according to its use.2、 Site selection, preparation and application of sufficient basic fertilizer1. Site selectionRice is a crop that likes fertilizer and water, is warm and warm, needs more oxygen and is afraid of waterlogging. Too acid, too sticky and poor soil will make maize grow poorly. Therefore, it is advisable to select loam or sandy loam with convenient drainage and irrigation, convenient management, PH 6.5-7 and medium fertility.2. Land preparation and basic fertilizer applicationGood soil preparation is the prerequisite for preserving seedlings. After selecting the land, carry out deep ploughing and raking. Generally, two ploughs and two rakes should be carried out, and the depth of the tillage layer should be more than 30 cm, so as to meet the quality requirements of "flat, fine soil, sufficient moisture and high fertilizer". After land preparation, set out and open the ditch according to the double-row planting spacing of 120~140 cm, and apply 1000 kg of decomposed farmyard manure, 50 kg of bean cake and 50 kg of superphosphate as basic fertilizer strips in the ditch; In order to facilitate drainage and irrigation, ditches should be opened for border in combination with land preparation, and drainage ditches should be built on all sides. The border shall be flat and the ditches shall be straight, the ditches shall be connected, and the drainage and irrigation shall be smooth.3、 Seed treatment and sowing1. Select good varietiesThe suitable varieties should be high and stable yield, good quality, disease resistance and lodging resistance, and can meet the market demand and sell well. At present, "Yedan 4", "Yedan 13", "Zhongdan 321" and other varieties are selected for feeding corn. Special varieties such as "Tiannuo 1" and "Suyu 1" are selected for fresh corn. Generally, the seed consumption per mu of direct seeding field is 1500-2000 grams.2. Seed treatmentBefore sowing, carefully screen the seeds with bright color, consistent size, full grain and high germination rate. Ensure that the purity of seeds is at least 98% and the germination rate is at least 85%. In addition, we should eliminate inferior seeds, such as those with mildew, rot and too small particles. Then the seeds are dried. Generally, a good weather is selected one week before planting to dry the seeds outdoors. First, the corn seeds are spread evenly, and the thickness is kept at about 5cm. Select a windward and sunny place to turn at any time, so as to ensure that each corn seed can be exposed to light and dry for two or three days. Then the seeds are coated. After drying the corn seeds, the seeds are coated two or three days before sowing. In this process, the seeds should be evenly stirred in a place with backlight and leeward. After the coating treatment, the corn seeds should be naturally dried in the shade, and then harvested for sowing.3. Seeding technologyFor corn, agricultural experts put forward "seven points depend on sowing and three points depend on management", which shows how important the quality of corn sowing has on the yield. During the germination of corn seeds, the soil needs to provide enough water. Generally, the water content suitable for seed germination in the soil needs to reach 70% - 75%. When sowing in spring, if the seeding layer is shallow, the soil above the seeds will lose moisture when it is time for seed germination after 10 days. Once the seeds cannot absorb enough water, they will "dry seed". This will lead to the lack of seedlings and ridge cutting of corn, and reduce the yield. If the planting plot has good watering conditions, the soil moisture can be properly watered before sowing according to the soil moisture content, so as to ensure that the soil has sufficient moisture before sowing, so as to ensure the germination and emergence of seeds. If there is no better watering condition, we should seize the opportunity to sow seeds in time after the rain. During the seeding process, wet soil should be selected, with a depth of about 3.5-4.5 cm, so as to achieve the goal of preserving seedlings at one time and achieving full and strong seedlings.  4、 Scientific fertilizationIn the process of fertilizing corn, the principle of "light in front, medium in weight, and supplement in the rear" should be followed. Corn has a large demand for nitrogen, phosphorus and potassium. The absorption of the three elements in the whole growth period is more nitrogen, followed by potassium, and less phosphorus. Therefore, the fertilization of corn is mainly to increase nitrogen fertilizer, combined with phosphorus and potassium fertilizer. Generally speaking, the seedlings (1~6 leaves) grow slowly, the plants are small, and the nutrients absorbed are also small. At this time, the amount of fertilizer should account for about 10% of the amount of fertilizer. The growth is very fast from jointing to flowering (7~16 leaves). At this time, it is the formation and development period of male and female panicles. The nutrient absorption rate is fast and the quantity is large. It is the critical period for the plant to need nutrients. At this time, sufficient nutrients can be supplied to promote the number and size of panicles. At this time, the amount of fertilizer should account for about 60% of the total amount of fertilizer, and the absorption rate gradually slowed down in the later stage (after 17 leaves), and the amount of absorption also decreased. The amount of fertilizer should account for about 20% of the total amount of fertilizer. The application ratio of nitrogen, phosphorus and potassium is generally about 3:1:2.8. At the seedling stage, potassium fertilizer, organic fertilizer, phosphorus fertilizer and zinc fertilizer can be applied at one time. For phosphate fertilizer, it must be applied deeply, and the effect of increasing yield is obvious when the depth is about 15 cm.1. Management of seedling stageThe seedling stage of maize is the vegetative growth stage formed by rooting and leafing, stem, node and leaf differentiation, and most of the root system is formed at this time. The main goal of seedling management is to promote root development, cultivate strong seedlings, achieve complete, complete and strong seedlings, and lay a good foundation for the growth of the spike and grain stage.(1) Seedling fixation and thinning: master the principle of "removing the weak and keeping the strong, keeping the dense and thin, orienting, keeping the even and keeping the strong seedlings". Seedling fixation is generally carried out when five true leaves are left, and one strong seedling is left in each hole. At the same time, the seedlings are checked and repaired, the seedlings are moved with soil, and sufficient rooting water is poured to ensure the survival of the seedlings. If there are too many seedlings missing, it can be solved by replanting seeds.(2) Inter-tillage and weeding: maize seedlings can be inter-tillage for 1-2 times, combined with fertilization and proper soil cultivation. The depth of intertillage shall be shallow beside the seedlings, deep in the row, shallow before and deep after seeding, and pay attention to the prevention and control of diseases and pests.(3) Water and fertilizer management: at the time of 5~6 leaves, apply seedling fertilizer for the first time, apply 7.5~10 kg of urea per mu, open a ditch in the middle of the border, and then cover the soil. In case of water shortage in the seedling stage, irrigation should be carried out in time, and ditch irrigation is appropriate. In case of rainy days, wet soil and ponding, pay attention to open deep ditches to drain ponding and improve soil ventilation conditions.2. Management of ear periodThe goal of field management at the ear stage is to attack the stem and ear, prevent water and fertilizer deficiency, and make the plant neat, the stem nodes thick and short, the leaves wide and thick, the root thick and large, and the female and male ear develop well.(1) Water and fertilizer management: at the time of 8~9 leaves, the second topdressing, that is, the application of straw fertilizer, accounts for about 25% of the total amount of fertilizer, and 10 kg of Hefei compound fertilizer plus 7.5 kg of potassium chloride per mu is applied in the form of strip fertilizer. At the time of 14~15 leaves (big bell stage), the third fertilizer application, that is, the application of spike fertilizer, accounts for about 35% of the total amount of fertilizer application. Each mu of fertilizer is applied with 20 kg of compound Hefei and 10 kg of potassium chloride, combined with large soil cultivation. After 9 leaves and 15 leaves, topdressing outside the root was carried out once, and 50 grams of rare earth or 800~1000 times of potassium dihydrogen phosphate were sprayed per mu. From jointing to heading, the plant of maize starts to grow vigorously and needs much water, especially before and after heading, which is the critical period of water demand for maize. At this time, water shortage, poor development, inconsistent flowering of male and female, affect pollination, resulting in bald head, lack of grain or empty stem, so soil water capacity should be kept at 70~80% during this period. In areas with plenty of rain, attention should be paid to ditch drainage. The damage period of corn borer is from the bell mouth to the heading stage. It is necessary to spray 500~800 times of trichlorfon or a mixture of chlorpyrifos+Bt powder to control the corn borer.(2) Inter-tillage and soil cultivation: in order to prevent soil hardening, eliminate weeds, improve the growth function of root system, and promote the multiple and deep roots, the tiller and soil cultivation should be carried out according to the soil and weed conditions at the heading stage. Generally, 1~2 times of intertillage shall be carried out between jointing and heading, and 2~4 inches of deep intertillage shall be carried out between rows to cut off some hairy roots, stimulate multiple new roots, and enhance the ability of drought resistance and lodging resistance. In the "big bell mouth" period before tasseling, plough once more shallowly and raise the soil ridge.3. Management of heading and fruiting periodThis period is the key period to determine the number of effective panicles, the number of solid grains per panicle and the grain weight. At this time, we should mainly pay attention to the appropriate amount of fertilizer supplement (10 kg of urea), drought resistance and drainage, artificial pollination and other work. When heading, flowering and grouting, irrigation should be carried out in time to keep the soil moist and meet the water requirements of the plant. However, irrigation should not be flooded, and it is better to irrigate horse water. Pay attention to drainage in rainy days to avoid waterlogging and anoxic injury to roots. During the flowering period of corn, in case of bad weather, artificial pollination should be carried out for 2-3 times, usually at 9-11 am on sunny days, to reduce the lack of grain and baldness.5、 Pest controlIn principle, prevention should be given priority to comprehensive prevention and control, and early detection and prevention should be carried out in management.The prevention and control of aphid diseases can be achieved by seed dressing. Dwarf disease, commonly known as the Clivia phenomenon, is caused by underground pests that damage the roots, and then infect the virus. Once the disease occurs, it will almost disappear. The control method is to mix seeds with carbofuran seed coating agent. The dosage of carbofuran is 20%, and the low value should be greater than 7%, but less than 7% has no effect. Yellow seedling disease, corn seedling disease, underground pests damage the taproot, and then infect the bacteria, which are often mistaken for top rot. Once the disease occurs, The production reduction is serious. The prevention and control method is to use carbofuran seed coating agent to mix seedsMaize diseases mainly include leaf spot, rust and sheath blight. Insect pests mainly include corn borer, armyworm, corn aphid, cotton bollworm, small land tiger, etc. For chemical control, large and small leaf spot and rust can be sprayed with 500 times of 50% carbendazim, and sheath blight can be sprayed with 500 times of 5% jinggangmycin. Corn borer and armyworm can be sprayed with 10% cypermethrin 2000 times and Bt powder 800 times, corn aphid can be sprayed with 20% Kangfuduo 3000 times, cotton bollworm can be sprayed with Bt powder 800 times and Tianli powder 800 times.

Chemical control and lodging resistance of rice

Rice lodging is a difficult planting problem in the process of rice planting management. Because rice is prone to extreme weather such as strong wind and precipitation in the later stage of growth, once lodging is caused, it will affect the yield in the later stage. Therefore, we must pay attention to the problem of rice lodging in the process of rice planting and management.1、 Causes and solutions of lodging1. The field is not sunned in time, the field is not sunned in place, and the root system cannot be well planted, resulting in the root system is not firm and prone to collapse.2. Inappropriate management of water layer and long-term deep water condition of rice resulted in soft stems, long basal internodes and reduced root hypoxia resistance.3. The planting density is too large, resulting in dark fields and thin stems; The transplanting depth is deep, the tillering node is high, the seedlings are long and easy to collapse.4. The main reason for unreasonable fertilization is that too much nitrogen fertilizer is applied too late, the stems are thin and weak, and prone to lodging.5. The occurrence of serious diseases and insect pests is prone to lodging; Disaster weather such as hail caused rice to collapse.In order to reduce the probability of rice lodging, measures should be taken such as reasonably controlling the water content of the rice field, timely sunning the field and putting it in place, reasonably controlling the density of seedlings and not too deep, controlling the amount of nitrogen fertilizer, and timely preventing and controlling diseases and pests. The important measure to prevent rice lodging is chemical control of rice, that is, plant growth regulator control. The chemical control of rice must be used from the early stage of tillering to the early stage of jointing according to the growth trend in the field, and the appropriate dosage must be mastered.Calcium tranexate: the rice chemical control agent is Quanfengshi Bida, and the effective ingredient is 5% calcium tranexate. Shipida is a new generation of chemical control and production increasing agent of Quanfeng Company, which has the characteristics of high activity and no residue. The effervescent granule dosage form makes the drug use more environmentally friendly. On the one hand, calcium cyclamate can reduce the length of internode, dwarf the height of plant base, increase the mechanical strength and improve the lodging resistance of rice; On the other hand, it can reduce the rate of shrunken grain and increase the number of solid grains, thus increasing the yield per unit area. Tranexate calcification solves the contradiction between lodging resistance and high yield of rice. On the premise of ensuring a certain plant height and planting density of rice, it can promote the filling of inferior grains of rice, improve the lodging resistance and yield increase ability of rice from the biological characteristics, so as to achieve the purpose of cultivation regulation.Advantages of calcium cyclamate compared with triazole control products:1. High activity of leaf surface absorption2. Short half-life, low toxicity and no residuePaclobutrazol: use 100~133 g of 15% paclobutrazol wettable powder per mu, add 100 kg of water to prepare paclobutrazol solution with a concentration of 150~200 mg/L. Spray the stems and leaves with the prepared solution before jointing, which can shorten the internode, thicken the stem wall, develop the mechanical tissue, and effectively prevent lodging.CCM: At the beginning of jointing, 50~100g of 50% CCM water solution and 50 kg of water per mu are added to prepare the concentration of 500~1000mg/L of CCM solution. Spraying on the stems and leaves can make the rice plant short and strong and prevent lodging.Ethephon: For late-season rice seedlings, spray 40~50 kg of Ethephon solution with a concentration of 3000 mg/L on the leaves per mu, or spray 50 kg of Ethephon solution with a concentration of 1500 mg/L on 20~30 days after planting in the field, which can effectively inhibit the growth of plant height and increase tillering after treatment.2、 Principles of rice chemical control:The main role of rice chemical control is to reduce the spacing of 1-3 nodes at the base. The formation period of the base node is the tillering stage of rice. At this time, the application of pesticide can shorten the length of the base node, increase the thickness of the base node, dwarf and take root, and promote the absorption of water and fertilizer; Promote the formation of silicified cells in rice, improve the flexibility and strength of stems, and effectively improve the lodging resistance of rice in the later stage. At the same time, it can also increase the effective tillering quantity, reduce the ineffective tillering, make the leaves dark green, improve the photosynthetic efficiency, strengthen the plant, coordinate the transformation from vegetative growth to reproductive growth.3、 Mistakes of rice control:Rice chemical control is an important measure to prevent lodging, which is widely used in rice production. However, there are some misunderstandings in actual production. One is that people are blind to the selection of chemical control agents. The second is that people mistakenly believe that the shorter the rice is, the better the rice is. The stems and leaves of plants are the source of organic matter production and yield formation, which is called the source of plants. The ear of rice is the storage organ of yield, which is called the sink of rice. This is the source-sink theory. The source and sink promote and restrict each other. The source and sink promote each other, and the sink promote the source. The source and sink can not have the output that can only be achieved through harmonious development. If we blindly pursue rice dwarfing, then the source of rice cannot be guaranteed, affecting the high yield of rice. The chemical control of rice can shorten the internode 1-3 at the base, thereby reducing the plant height, enhancing the flexibility of the stem, promoting rooting, increasing the effective tillering, and promoting the transformation from vegetative growth to reproductive growth. This is our original intention of chemical control of rice to prevent lodging, not to blindly reduce the plant height.

Rice planting technology (II)

4. Field management, disease, pest and weed controlAfter transplanting, there will usually be empty planting. Therefore, we should do a good job of seedling inspection after transplanting. If there are holes, we should fill in high-quality rice seedlings in time to ensure the planting density and basic number of rice seedlings. In addition, the field sealing agent can be sprayed properly before and after transplanting to inhibit the germination of weed seeds in the paddy field. Weeding should also be done well after transplanting to prevent weeds from seizing the growth nutrition of rice seedlings. At the same time of weeding, we should also do a good job in insect control. The insect pest of rice is relatively serious. The common one is leafminer, which can be properly sprayed with insecticide for control. Pay attention to the dosage to prevent harm to rice.1. Two to three days before sowing or at the seedling needle setting stage, use 75 to 100 ml of 50% butachlor emulsifiable concentrate per mu to spray 30 kg of water on the bed surface, or after sowing rice, when the seeds are exposed or at the needle setting stage, use 100 ml of 30% suffert emulsifiable concentrate per mu plus water spray to seal the weeds on the bed surface, and the safety of the former is not as good as that of the latter.2. For emergent barnyard grass, 50% quinclorac wettable powder can be sprayed spray per mu according to the product instructions.3. When seedlings have two leaves and one heart, use 20% methyl pyrifos 500 times solution or Kangli 1500 times solution for spray.4. In order to prevent and cure the disease, we should take the initiative to prevent and cure the disease when it is found. If there are dead seedlings in a large area, it will be out of time. The way to check the disease is to see if the leaf tip spits water. If the leaf tip does not spit water, it is a sign of the occurrence of the disease.5. Each mu of chilo suppressalis, rice thrips, and gray planthoppers is treated with 200ml of insecticidal double and 200ml of BT insecticide by spray, so as to achieve the simultaneous treatment of insects and eggs.6. To prevent and control mole crickets in the seedbed, 1500 times spray can be used to attack people, as well as control chilo suppressalis, thrips, rice weevil, etc.7. Before transplanting rice seedlings, it is necessary to use 500 times liquid of disease enemy or 500 times liquid of Far East Junxing or 500 times liquid of Bem to spray according to local conditions to prevent rice blast, flax leaf spot and bacterial blight, and prevent seedlings from entering the field with diseases.8. Control of stripe leaf blightThe stripe leaf blight is transmitted by the grey planthopper, so the rice planthopper should be controlled:① Combined control of wheat aphid and rice planthopper.② In the mature stage of wheat, the planthopper in the wheat field moved into the seedbed due to the deterioration of the living conditions. Before the wheat ripens to the transplanting stage, the rice seedling field should be controlled with 10% aphid clear or 20 grams of dipyridamide to 30 kg of water for 2-3 times. Control the vector of the virus to control pests and prevent diseases. Morpholine guanidine copper spray can also be used for control, or 30-50g of dry streaked leaves can be evenly sprayed with 30kg of water to inhibit the development of rice streaked leaf blight5. Application of plant growth regulators in riceThe rice cultivated by soaking seeds with uniconazole has many tillers and short stature. After transplanting into the field, it will turn green quickly, lose seedlings slightly, grow early and grow quickly, and the effective tillers and effective panicles will increase, achieving the effect of increasing panicles and yield. The sensitivity of different rice varieties to uniconazole is significantly different, and the use concentration should be different.Spraying 100mg/L uniconazole at the stage of one leaf and one heart for wet seedling raising, spraying 100mg/L uniconazole at the stage of one leaf and one heart for two stage seedling raising and greenhouse seedling raising, and spraying 100mg/L uniconazole at the stage of one leaf and one heart for 15 days after transplanting, are effective measures to cultivate strong seedlings and improve yield. Uniconazole should not be used in dry seedling stage.At the stage of two leaves and one heart of rice, water spray with 40 grams of 15% paclobutrazol per mu. The spraying shall be uniform, and the missed spraying and re-spraying shall not be allowed to make the seedlings grow uniformly. One week before transplanting rice seedlings, 5g rooting agent can be used per mu, and 15kg water can be added to the leaf spray to promote the seedlings to grow out of the root primordium. After transplanting, the seedlings will grow and elongate rapidly.

Rice planting technology (I)

Rice is divided into indica rice and japonica rice, early rice and mid-late rice, glutinous rice and non-glutinous rice according to the type of rice. It can be divided into conventional rice and hybrid rice according to the way of planting. There are other classifications, which can be divided into paddy rice and floating rice according to soilless cultivation or not; According to the life cycle, it can be divided into seasonal rice and "lazy rice" (over-year ratooning rice); According to height, it can be divided into ordinary rice and giant rice of about 2 meters; According to salt and alkali tolerance, it can be divided into ordinary freshwater rice and "sea water rice".In rice, seeds are usually germinated to produce new seeds, which is a growth cycle of rice, that is, the growth period. The growth period can be divided into seedling stage, turning green stage, tillering stage, long spike stage (spike differentiation stage) and seed setting stage.Seedling stage: including germination, germination and trefoil stage.Greening period: the buffer period for rice survival from seedling field to Honda after transplanting.Tillering stage: including initial stage, peak stage, final stage (high tillering stage) and effective tillering termination stage which determines the key period of spike number.Long ear stage: including ear differentiation stage, jointing stage and booting stage when the sheath of flag leaf bulges.Seed setting stage: including heading and flowering stage, milk maturity stage, wax maturity stage, yellow maturity stage and full maturity stage.In order to do a good job in rice seedling breeding, we should select good varieties, do a good job in selecting and drying seeds, soaking seeds with chemicals, and accelerating germination with proper temperature, strengthen the management of seedling fields, and adopt the "four control and one prevention" technical measures to control the sowing date, the sowing amount, the water, the length, and the disease and insect pests, so as to achieve a complete seedling.1. Seed treatmentBefore planting, select excellent rice seeds, and select well-adapted pure and full seeds according to local weather changes and soil conditions. Then soak the seeds and disinfect them. When disinfecting, pay attention not to damage the seeds. Disinfectants such as strong chlorine essence can be used, which can effectively disinfect the seeds without causing damage. After soaking the seeds, take them out and wrap them with wet gauze to accelerate germination. Control the temperature at about 31 degrees. Pay attention to the pile turning when the temperature increases. When most of the seeds are exposed, reduce the temperature to about 25 degrees. During germination, pay attention to the temperature change, control the temperature within the appropriate range, and timely sow and raise seedlings after the germination is done in the shade and air.2. Seedling raising and transplantingThe common method of raising rice seedlings in China's rural areas is to raise seedlings in the seedling tray, prepare the nutrient soil in the seedling tray, and apply sufficient base fertilizer. The base fertilizer is mainly farmyard fertilizer, and mix it with the soil evenly with appropriate amount of compound fertilizer. When the temperature is above 7 ℃, timely sow, cover with fine soil after sowing, improve the soil temperature, and ensure that the seeds can germinate normally and all kinds of nutrients required for germination. Seedling management should be done well after emergence. High-quality rice seedlings are the key to ensure successful rice planting. When the seedlings grow to about 8 cm, they can be transplanted.3. Water and fertilizer managementIt is very necessary to manage the water content of rice. It is necessary to ensure that shallow water is used frequently at the tillering stage, sufficient water is used to dry the field at the seedling stage, shallow water is used frequently at the young spike differentiation stage, the water layer is maintained at the heading and flowering stage, and dry and wet alternate at the milking stage.It is very important to drain and sun the field after the rice tillering stage and before the young spike differentiation. It can reasonably control the ineffective tillers, further improve the lodging resistance ability, at the same time enhance the absorption of nutrients by rice, effectively improve the growth status of rice roots, and more conducive to the root down, thus improving the yield of rice.Fertilization of rice is also very important. The tillering stage of rice is the first stage in which rice needs a large amount of fertilizer, so the first topdressing should be carried out. Adequate nutrition can promote the growth of rice seedlings, ensure the fullness of rice quality, and improve the yield. In the middle and later stages, fertilizer can be applied appropriately according to the soil and rice growth.In the process of cultivation, the amount of fertilizer applied to rice should be reasonably controlled. The fertilizer should be used in stages and batches, with the former heavy and the latter light, and the latter should pay attention to the supplement of phosphorus and potassium fertilizer. In addition, silicon and zinc have a great impact on the yield and quality of rice.Base fertilizer: mainly organic fertilizer, supplemented by quick-acting fertilizer. Generally, 2000~3000 kg of organic fertilizer+7~8 kg of urea, 30~40 kg of superphosphate, 8~10 kg of potassium chloride or 30~40 kg of balanced compound fertilizer are applied per mu.Tillering fertilizer: it can be applied as early as possible after transplanting and turning green to promote the growth of low-node tillers, and play the role of ear enhancement, which can be carried out twice. After turning green for the first time, apply 7~8 kg of urea or high-nitrogen compound fertilizer per mu, and appropriate amount of calcium sulfate and zinc sulfate to promote tillering; For the second time, 7~8 kg of urea or high-nitrogen compound fertilizer per mu was applied at the peak tillering stage to ensure the orderly growth of the whole field and to protect the tillering and ear formation.Ear fertilizer: after the rice is sunned, the ear fertilizer should be applied in time to promote the development of young ears. The application of ear fertilizer should be carried out from the time of closing to the time of jointing. It is better to apply the ear fertilizer when the young ear differentiation is 1 to 2 stages. About 20 kg of potassium chloride+8 to 10 kg of urea should be used per mu.Granular fertilizer: 5~7 days before the break, if the leaf spike is too green, it will be harmful to the later filling and the maintenance of green leaves. At this time, 3~5 kg of urea per mu will be applied to avoid premature leaf senescence after the break heading.Foliar topdressing: rice can be mixed with foliar fertilizer to topdressing outside the root during the jointing to filling period, in combination with disease and pest control drugs. The fertilizer can be selected from phosphorus and potassium source and sink, urea, silicon fertilizer, boron fertilizer, etc., and applied in the critical period of fertilizer demand such as break, booting and heading.The picture is from the network. If it is the same, please contact to delete it

Application of plant growth regulators in fruit trees -- Citrus (II)

Section 2 Control the growth of summer shoots1. Branch growthThe citrus bud is covered by several pieces of undeveloped fleshy first leaves. Each leaf axil of the first leaves has a bud and several latent buds, so several new shoots can often sprout on a node. Using this feature, manually erase the first sprouted shoots, which can promote the germination of more new shoots. A few days after the elongation of the new shoots of citrus stopped, the apex of the tender shoots could fall off automatically, which is called the phenomenon of "self-cutting" of the top buds. Therefore, citrus shoots have no terminal buds, only lateral buds. Citrus buds are divided into leaf buds and flower buds. Leaf buds only sprout branches, while flower buds can not only sprout branches, but also blossom and bear fruit. Citrus shoots can be divided into spring, summer, autumn and winter shoots according to the occurrence period. Spring shoots generally sprout from February to April and are important branches in the year. Spring shoots can be divided into flowering branches and vegetative branches due to their different properties. After flowering, flowering and fruiting at the top or leaf vein. The vegetative branch has only leaves and no flowers. It mainly produces nutrients. After development, it can become the fruiting mother branch of the next year. Therefore, the development of spring shoots affects the yield of the year; Summer shoots sprout from May to July. They grow vigorously in high temperature and rainy season. The branches are thick and long, and the leaves are large and thick. Summer shoots sprout irregularly under natural growth. When summer shoots sprout in large numbers, they often compete with young fruits for nutrients, which aggravates physiological fruit drop. Therefore, in addition to expanding the use of young trees to fill the crown, production should control summer shoots more; The autumn shoots are harvested in batches from August to October. The growth potential is stronger than spring shoots and weaker than summer shoots, and the leaf size is between spring and summer shoots. Young trees and early fruit trees have a large number of autumn shoots. The robust autumn shoots are excellent bearing mother branches with good flower quality and reliable fruit setting. In order to increase the number of flowering and fruiting in the next year, the measures of wiping out summer buds and promoting the release of autumn shoots were adopted in cultivation; In areas and years with warm winter, winter shoots can be sprouted around November, but the number is small, and it is not easy to ripen, and the low temperature is often affected by freezing. Some winter shoots can bloom in the next year, but the flowers and fruits fall seriously. Winter shoots have no use value in production, and should be pruned more.2. Technical measures to control the growth of summer shoots(1) Spraying paclobutrazol with a concentration of 250~1000mg/L on the leaves of citrus during the summer shoot occurrence period can shorten the summer shoot by 50%~75%, shorten the internode, slightly reduce the number of summer shoots, increase the summer leaves, increase the fruit setting rate by 2%~4%, increase the yield by 6%~48%, thin the peel, and increase the edible rate. When applied in production, the concentration of satsuma mandarin is 750 mg/L, Ponkan mandarin is 1000 mg/L, and local early is 500 mg/L. Tong Changhua et al. (1987) advanced the spraying period to the end of spring shoot elongation, which had a more significant effect on inhibiting the occurrence and elongation of summer shoots and improving fruit setting rate and yield. The sugar orange fruit-bearing trees were sprayed with 500 times of liquid once at the second physiological fruit fall (when the summer shoots were about to be pulled out), and the second time every 20 days. PP333 was sprayed on the tree crown, and the germination amount of the summer shoots was 35%~37% of that of the control sprayed with water. When the spraying concentration of dark orange is 250~750mg/L before the occurrence of summer shoots, the summer shoots can be shortened by 11%~26%, and the inhibition effect will be strengthened with the increase of the application concentration, without affecting the fruit development and quality. The application of paclobutrazol with a concentration of 1000mg/L can make the "generation" of potted plants grow slowly and robustly, and can inhibit the growth of roots, meeting the requirements of potted plants. Mei Zhengmin et al. (2009) suggested that the effect of the use of penicillin 500mg/L+paclobutrazol 700mg/L in production was better when the new shoot length was about 2cm, and the number of drug use should not exceed two times a year.(2) During the summer shoot emergence period of the 3-year-old Weizhang satsuma mandarin, the number of summer shoots of the former is only 65.8%~86.9% of the control, the branches are shortened, the fruit setting rate is increased by 5.1%~5.6%, and the yield is increased by 40%~50% when the concentration is 2000~4000 mg/L or the concentration is 500~1000 mg/L of the water solution of chlormequat is sprayed at the rhizosphere of each plant; The number of hair shoots of the latter decreased by 1-2%, the fruit setting rate increased by 1.4%~3.3%, and the yield increased by about 10%. The fruit quality is the same as the control. However, the fruit irrigated with 1000mg/L chlormequat aqueous solution in the rhizosphere is orange-red, bright and pleasing to the eye, and full of luster.Section 3 Flower and fruit thinning1. Flower and fruit thinning mechanismToo many arboreal flowers and fruits consume the nutrition of the tree, inhibit the growth of new shoots, form large and small years, make the tree weak, and even die due to too many fruits. Artificial fruit thinning is adopted, with large labor consumption and high cost. Y. Kamuro et al. (1982) found that the ethylene content in the leaves of satsuma mandarin rose after spraying indole ester, which suggested that during the physiological fruit fall of citrus, spraying indole ester could promote the occurrence of ethylene, thus accelerating the formation of separation layer and promoting fruit fall. Compared with NAA and ethephon, the amount of ethylene produced by indole ester is less than that produced by NAA and ethephon, but the duration of ethylene production is longer, which is consistent with the late and longer peak of young fruit abscission reported by Shi Xuegen after spraying indole ester (Wang Yangjie et al., 1995).2. Technical measures for chemical flower and fruit thinning(1) Naphthylacetic acid is used for fruit thinning of satsuma mandarin. It is generally effective to spray wine 20~30 days after blooming. In areas where the temperature rises quickly in spring and flowering is relatively early, it is better to spray wine 20 days after blooming, and on the contrary, it is better to spray wine 30 days after blooming. The application concentration is 200 mg/L. When the amount of fruit set is very large and the temperature is low, the concentration of alcohol that can be sprayed is 300mg/L. Spraying at the above concentration and time can maintain the leaf-fruit ratio of satsuma mandarin at (20~25): 1, reaching the degree of artificial fruit thinning. (2) Indole ester The common concentration of indole ester is 100-200 mg/L, and it is ideal to spray it 30~50 days after full bloom, among which local early and early maturing satsuma mandarin is 30 days after full bloom, and common satsuma mandarin is 40~50 days after full bloom. One week after spraying, a large number of small fruits turn yellow and fall off. The peak period of fruit falling lasts for 5~10 days, and the fruit falling period lasts for about 2~3 weeks. It can make the mature fruit uniform in size, reduce the peeling, color early for 5~9 days, increase the sugar content, and improve the content of amino acids in the fruit. The removal rate of satsuma mandarin, local early and ponkan mandarin can reach 20%~60%. Generally, the smaller the fruit diameter is, the easier it is to be removed. With the increase of the fruit diameter, the removal rate gradually decreases. However, orange trees with extremely weak growth, more flowers, more fruits, smaller fruit shape or excessive growth and less flowers are not suitable for application. In addition, it is not allowed to increase the concentration of liquid medicine at will to avoid excessive fruit thinning.Section IV Control of flower amount1. Flower bud differentiationMost citrus species in subtropical areas undergo flower bud differentiation before and after fruit ripening in winter and before sprouting in the spring of the next year, but the same variety also differs in the same place due to year, tree age, nutritional status, tree vigor, fruit status, etc. In addition, on the same plant, spring shoots differentiated earlier, followed by autumn shoots and summer shoots; The short shoots differentiated earlier than the long shoots; The bud at the base of the long branch is earlier than the bud at the top. For example, in Chongqing, Huang Huibai et al. (1991) observed that the flower induction period of Dark Orange was from the end of September to the end of October; Liu Zhongxiao et al. (1984) reported that the induction period of orange flowers in Fulingxia was from early September to mid-October. In central China, Wenzhou mandarin oranges in Yichang, Hubei Province began to undergo flower bud differentiation in late December (Chen Jiezhong, 2003). Citrus flowering is a complex physiological and biochemical process affected by many internal and external factors. It is not only the accumulation of nutrients, the dynamic changes of hormones, but also controlled by genetic genes. Citrus is a perennial woody plant, which is greatly affected by external factors. Some accidental factors can stop the flower bud differentiation process. Low temperature and drought promote the transformation of citrus tree physiology to the direction conducive to flower bud differentiation. Circular peeling can cause the same physiological changes as water control treatment, and has a significant effect on promoting flower bud differentiation. Ringing increased the RNA content and RNA/DNA ratio in shoots of Miyagawa satsuma mandarin and dark orange (Huang Huibai et al., 1991) during flower bud breeding, and promoted flower bud initiation. Spraying GA3 decreased the RNA/DNA ratio and inhibited flower bud initiation; Defoliation inhibits flower bud breeding, has no effect on the DNA content and GA level of shoot tip, but reduces the RNA content and IAA level of shoot tip, and delays the accumulation of ABA and CTK (Li Xingjun et al., 2002). In autumn and winter, paclobutrazol treatment inhibited GA synthesis and nutrient growth of citrus branches and leaves, increased carbohydrate level and promoted flower bud differentiation.Citrus flower bud differentiation is closely related to plant hormones. Bangerth believes that cytokinin (CTK) plays a role in promoting flower bud development. At the stage of citrus flower bud differentiation, the level of cytokinin in citrus flower bud gradually increased and reached a higher level at the early stage of morphological differentiation. Gibberellin (GA) is the main flower inhibiting hormone (Li Jinxue et al., 2012). GA is the main inhibitor of flower formation in most fruit trees. External application of GA can counteract the effect of ring cutting on flower formation. The content of GA1, GA19 and GA30 in the vegetative branches and leaves of satsuma mandarin also showed a peak. During the flower bud differentiation of satsuma mandarin, the content of GA in big branches decreased continuously during the whole flower bud induction period. Gold-schmidt et al. analyzed the content of endogenous hormones in mixed branches, vegetative branches and pure flower bud branches of lemon tree, and found that the level of GA in vegetative branches was higher, while that in pure flower bud branches was lower. Citrus bears less fruit in the early year. Through ring cutting, water control and flower promotion, the flower bud differentiation of citrus was significantly promoted, and the content of GA in the branches during the physiological differentiation of flower buds was reduced. Abscisic acid (ABA) may play different roles in different stages of flower bud differentiation. Ruan Yongling and others found that ABA was at a low level in the flower bud induction stage and had the effect of inhibiting flower bud differentiation, while rising to a higher level during the formation of flower primordium had the effect of promoting flower bud differentiation. ABA can obviously stop the vegetative growth of citrus trees, and may indirectly affect flower bud breeding. Kojema et al. believed that ABA promoted the flower bud breeding of satsuma mandarin because ABA could counteract the effect of GA3, increase the concentration of sugar in the vacuole of citrus bud, and increase the strength of the pool. When people have studied the relationship between citrus flower bud inoculation and hormones for a long time, they found that flower bud inoculation is a comprehensive result of the interaction of various hormones in time and space (Li Jinxue et al., 2012).2. Technical measures for regulating flower amountThe plant growth regulators that can effectively promote the differentiation and formation of citrus flower buds include chlormequat, paclobutrazol, nucleotides, etc. Growth substances induce the flowering of citrus seedlings, and it is only possible for young trees to develop through sexual stage; The effect of application on adult trees is significant only at the physiological differentiation stage of flower buds. After the physiological differentiation stage, application has some effects, but the effect is not significant.(1) Increase the amount of flowers① The nine-year-old seedlings of broad-skinned citrus, Satsuma mandarin, were sprayed with 2000 mg/L chlormequat or 2000~4000 mg/L butyrylhydrazide in the middle of September, and the flower amount in the following year increased by 118%~242% respectively. From September 15 to January 25, spraying 50mg/L of nucleotides every 10 days for satsuma mandarin in the initial fruit stage can increase the number of flower bud differentiation in the next year. The spraying effect in the middle of November is better, and the number of flower bud differentiation is nearly doubled. Tong Changhua et al. (1989) proved that spraying paclobutrazol before the physiological differentiation stage of flower buds can significantly promote flower formation, among which the appropriate concentration of satsuma mandarin is 700mg/L, and Ponkan mandarin is 1000mg/L; Spraying 200 mg/L cytokinin at the stage of flower bud morphological differentiation can also significantly promote the development of flower organs and increase the amount of flowers in the next year. From November to December, when the autumn shoots ripen, the granulated orange will be sprayed with 500 times of 15% paclobutrazol once, which has obvious flower promoting effect (Mao Shunhua et al., 2008). ② Qin Xuannan et al. (1994), a lemon species, sprayed paclobutrazol at the concentration of 300~400mg/L twice on the tree crown from late October to early November before the flower bud differentiation of Yulike lemon, which can significantly promote the proportion of flowering and normal flowers, and has certain effects on improving the fruit setting rate, cold resistance and reducing the abnormal defoliation rate in winter. In addition, in the middle and late August, spray BTOA (benzothiazole oxyacetate) twice in succession, which can promote the autumn flowers of Eurek lemon. CCM, butyrylhydrazide and MH-30 can also promote the differentiation of lemon flower buds. ③ Golden orange Golden orange blossoms many times a year and bears many fruits. Among them, the first "early dormant flower" accounts for about 80% of the annual fruit yield, and the fruit is large and high-quality, with significant economic benefits. If the concentration of paclobutrazol or butyrylhydrazide was 1000 mg/L or 3000 mg/L at the beginning of the first shoot germination, the "early dormant flowers" after the use of paclobutrazol increased by 10 times, and the "late dormant flowers" of the second shoot were significantly reduced. Although the total amount of flowers decreased, the economic benefits were extremely significant. On the contrary, Bejiu (Bs) has reduced "early summer flowers" and increased "late summer flowers", with insignificant economic benefits.(2) The experiment of reducing the amount of flowers showed that the effective period of gibberellin inhibiting the flower bud differentiation of Voringxia orange was the critical period of flower bud differentiation, that is, the physiological differentiation period (September) to the morphological differentiation period (November). The effect of advance or delay decreased. The appropriate concentration of spraying was 100-200 mg/L. In addition, the effect of flower inhibition in the next year is closely related to the fruit load in the current year, that is, the effect of flower inhibition is significant when the fruit is abundant in the current year, and on the contrary, it is relatively weak. From November to January of the next year, Shamoti sweet orange is sprayed with gibberellin with a concentration of 200 mg/L, once every two weeks. If it is sprayed to the end of December, it will not blossom in the next year, and if it is sprayed to the beginning of December, it will still blossom in the next year, but the flowering period will be delayed. The effect of inhibiting flower growth of satsuma mandarin by spraying gibberellin 100mg/L in January was significant. Clementine red orange was sprayed with the same concentration as satsuma mandarin in December, and the flower amount in the next year decreased by 75%. After spraying gibberellin to control the flowers, the spring shoots and leafy fruit-bearing branches in the next year increased significantly and grew vigorously. It should be used with caution in areas with severe late spring cold.The article is from the book "Application of plant growth regulators in fruit trees", and the content is for reference only.

Application of plant growth regulators in fruit trees -- Citrus (1)

Section I: flower and fruit protection1. Falling flowers and fruits(1) Physiological fruit dropCitrus flower and fruit fall can be divided into five stages: bud fall, flower fall, the first physiological fruit fall (10~20 days after flowering), the second physiological fruit fall (20~70 days after flowering without fruit stem falling from the honey tray), and fruit fall before harvest (fruit fall after fruit stabilization in June to before harvest). After the above process, the fruit setting rate is generally only 0.3%~5%. The main reasons for the low fruit-setting rate are the abnormal development of flower organs or poor fertilization, the insufficient nutrition of the tree body, the large number of summer shoots, the serious occurrence of diseases and pests, the bad weather or the hormone imbalance in the trees with stems, etc. The nutrients needed for the sprouting, spring shoot growth, flowering and early development of young fruit of the orange tree are mainly the storage nutrients of the previous year, while the amount of annual storage nutrients of each variety of orange tree is relatively fixed. Therefore, if the spring shoots of the orange tree grow too fast after sprouting and leafing, the storage nutrient consumption will be more, then the nutrient obtained from flowering and fruiting will be less, and the flowering and fruiting will cause a large number of flowers and fruits due to insufficient nutrients. The auxin and gibberellin are insufficient in the young fruit stage of citrus, especially in seedless varieties, which causes the fruit stalk to delaminate and cause flower and fruit drop. Navel orange is a parthenocarpic fruit, which mainly depends on the hormone produced by ovary to promote the expansion of young fruit. Abscisic acid inhibits growth and promotes fruit abscission. Gibberellin promotes cell elongation and fruit growth. The abscission of navel orange young fruit was positively correlated with the content of abscisic acid in the tree. The more abscisic acid content, the more fruit fell. There was a significant negative correlation between the abscission of navel orange young fruit and the content of gibberellin in the tree. The more gibberellin content, the less fruit abscission. The mechanism of gibberellin improving the fruit setting rate of navel orange is mainly that the high concentration of gibberellin improves the ability of fruit to transport nutrients, and the effect of gibberellin on ovary is to promote the metabolism of plant to the fruit (Tan Haiyu, 2003). Sweet oranges and satsuma mandarin have a large amount of young fruit loss in the first physiological fruit fall period, while red oranges have a large amount of young fruit loss in the second physiological fruit fall period (Wang Dajun et al., 1996). Cytokinetin (BA) has a significant effect on preventing the first physiological fruit drop, but it cannot prevent the second physiological fruit drop. The effect of gibberellin on reducing the first physiological fruit drop was weak; However, it can significantly inhibit the second physiological fruit drop. In citrus production, auxin and synthetic auxin 2,4-D are used to reduce pre-harvest fruit drop and delay fruit harvest. Applying 2,4-D to sweet orange trees will delay the shedding of flowers and young fruits, and eventually lead to the reduction of the number of mature fruits. However, it has also been reported that applying 2,4-D to navel orange trees will increase the number of fruits. Some other chemicals, such as chloropyrylphenylurea (CPPU) [1 - (2-chloro4-pyridyl) - 3-phenylurea], also inhibit the shedding of young citrus fruit (Wang Miao et al., 2009).(2) Abnormal flower and fruit dropIn recent years, the citrus production areas in the Yangtze River basin often encounter abnormal high temperature weather with daily average temperature higher than 25 ℃ and daily high temperature higher than 30 ℃ during flowering and young fruit stage, which is often accompanied by abnormal flower and fruit drop, which greatly reduces the citrus production in the affected areas. According to the research, the potted Xingjin satsuma fruit trees grow for 2 to 5 days under the simulated conditions of abnormal high temperature with daily average temperature of 26.8 ℃ and daily high temperature of 35 ℃. The average length of spring shoots increases by 4.3% to 78.2% compared with the control growing under the natural conditions with daily average temperature of 27.3 ℃ and daily high temperature of 33 ℃. At the same time, it promotes the occurrence of dormant buds of some citrus trees and increases the number of spring shoots by 5% to 15.3%. As the number of new leaves increases, the proportion of new and old leaves increases, resulting in excessive nutrient growth of spring shoots, increased consumption of stored nutrients, and insufficient nutrients for flower and fruit development, resulting in a large number of flower and fruit drop. According to the survey, if the proportion of new and old leaves of potted Xingjin satsuma mandarin is greater than 1, the flowers and young fruits in the orange tree will fall off when the abnormal high temperature is harmful.2. Technical measures for flower and fruit conservation(1) According to the test results of the Department of Horticulture of Zhejiang University, paclobutrazol was used to spray satsuma mandarin with 750 mg/L paclobutrazol or Ponkan with 1000 mg/L paclobutrazol in the evening of cloudy or sunny days at the flowering stage of satsuma mandarin and Ponkan. The young part of spring shoots should be sprayed when spraying. It can control the overgrowth of spring shoots, reduce the consumption of storage nutrients, and at the same time, the leaves turn green and thicken, enhance the ability to produce assimilation nutrients, ensure that flowers and fruits get sufficient nutrients, and significantly improve the fruit setting rate. However, the leaf area of orange trees decreased slightly after spraying paclobutrazol, which is a normal phenomenon and will not affect the growth and fruit of the next year. When using, first dissolve paclobutrazol with a small amount of water, and then add enough water to evenly spray the crown of the tree until the leaves drip. Due to the long residual effect period of paclobutrazol, in order to prevent the excessive inhibition of orange shoot growth caused by continuous use, it is recommended to use paclobutrazol after 1-2 years, and then stop using it for 1-2 years. At the same time, it is not suitable to use paclobutrazol during the flowering period and young fruit setting period of citrus, otherwise it will affect the growth and development of young fruit.(2) The rate of fruit setting was significantly increased when gibberellin was sprayed once on the crown of citrus trees with a concentration of 30~50mg/L after 2/3 and 10 days after the flowering of satsuma mandarin, ponkan mandarin and other citrus trees, while the rate of fruit setting was significantly increased when gibberellin was sprayed once with a concentration of 100~200mg/L on the young fruit of citrus trees with a small amount of flowers after flowering, and the effect of fruit preservation was 10 points significant.Due to the lack of endogenous hormones such as gibberellin, auxin and cytokinin produced by seed development, seedless sugar orange has a low level of endogenous hormones in fruit development, which can not meet the needs of growth and development, and a large number of fruit drops occur. Spraying 75% gibberellin (92O) powder 1g+water 35~50kg+0.4% urea+0.2% potassium dihydrogen phosphate+0.1% boric acid on the tree crown 20~25 days after flowering, and spraying it again every 15 days can significantly improve the fruit setting rate of seedless sugar orange. In addition, 100 mL of cytokine plus 200~300 kg of water or 500 mL of amino acid sugar phosphate plus 400 kg of water can also be added for spraying. If there are red spiders, aphids, Fenxun and other pests, they can also be mixed with pesticides for spraying (Ye Zizi et al., 2009).(3) In the first physiological fruit fall period, the concentration of cytokinin in the crown of the tree is 200~400mg/L, which is sprayed once every 10 days, a total of 2-3 times, which has a significant effect on improving the fruit setting rate of citrus (Hu Yaosheng, 1996).(4) At the flowering stage and the end of the first physiological fruit fall, the application of 0.1~0.5mg/1L of clopidouron (piromuron) on the canopy of satsuma mandarin can significantly promote fruit setting and increase fruit setting rate.(5) When gibberellin+benzyladenine was used in the young fruit stage of Washington navel orange, 250 mg/L gibberellin and 200 mg/L benzyladenine were used to coat the fruit, the fruit setting rate reached 31.78%, which was significantly higher than 0.85% of the control, and the yield was significantly increased. Citrus uses mixed solution of gibberellin and benzyladenine to keep flowers and fruits. The times and methods of application should be determined according to the type of citrus and the characteristics of falling flowers and fruits. Generally, for the citrus with less serious first physiological fruit drop, the first physiological fruit drop can be controlled by spray with 50 mg/L gibberellin, or the second physiological fruit drop can be coated with 100~500 mg/L gibberellin; For citrus with serious fruit drop in two times, the fruit can be coated with gibberellin 50-100mg/L plus benzyladenine 200-400mg/L before the first physiological fruit drop, and then sprayed with gibberellin 50-100mg/L before the second physiological fruit drop. Both the test and production practice have proved that the effect is more obvious when two or more substances are used in combination or in combination with topdressing outside the root, but the dissolution conditions of various substances must be paid attention to when compounding, and precipitation and turbidity are invalid. Secondly, we should also pay attention to the spraying on the leaf surface, as well as the topdressing outside the root, which should be carried out after 3pm every day. We should pay attention to the spraying on the back of the leaf, and the quantity should not be too much each time (Hu Ansheng, 1996).3. Measures to prevent abnormal flower and fruit drop caused by abnormal high temperature of citrusFirst of all, we must control the overgrowth of spring shoots to ensure that flowers and fruits get sufficient nutrients. At the citrus flower bud stage before the arrival of abnormal high temperature, spray the canopy with the concentration of 750 mg/L (satsuma mandarin) or 1000 mg/L (ponkan mandarin) of paclobutrazol solution, on the one hand, stop the growth of spring shoots ahead of time, mature the new leaves ahead of time, improve the photosynthetic capacity of the new leaves, increase the accumulation of assimilation nutrients in the citrus tree, and ensure that the flower and fruit development get sufficient nutrients; On the other hand, it can inhibit the number of dormant buds stimulated by abnormal high temperature, reduce the occurrence of new shoots, and reduce the consumption of new shoots on storage nutrients.Secondly, after the occurrence of abnormal high temperature, it should be remedied by spraying in time to reduce the degree of harm. According to Tong Changhua and others, spraying 2,4-D of banned acetic acid+8 mg/L or 2,4-D of gibberellin+8 mg/L with a concentration of 100 mg/L or 50 mg/L on the tree crown after half a day of abnormal high temperature can significantly reduce the harm of abnormal flower and fruit drop caused by abnormal high temperature; Li Xuezhu and others coated the fruit with 125mg/L gibberellin+100mg/L furfuraminopurine (kinetin) after the occurrence of abnormal high temperature in the flowering period, which has a significant effect on improving the fruit setting rate of Xingjin satsuma and Jincheng.4. Measures to prevent citrus fruit falling at low temperature in winter and before harvestFruits of many varieties, such as Fuling Summer Orange, need to be harvested from March to June next year after the winter solstice. Due to the relatively low temperature in winter, the water absorption capacity of root system is weak, and the content of auxin in the tree body is also reduced, which will cause a large number of fruit drop before and after the Spring Festival, causing heavy economic losses. Huang Dinggui applied 2,4-D with the concentration of 20~40mg/L to spray before the low temperature in November, which can significantly reduce the fruit drop caused by low temperature. If 0.1%~0.3% manganese sulfate is added to 2,4-D, the effect will be better. The reason is that adding manganese sulfate can reduce the activity of cellulase.Spraying 2,4-D20~50mg/L before or at the beginning of fruit falling can not only prevent fruit falling, but also reduce defoliation. The concentration of medium-maturing varieties of citrus should be controlled at 20mg/L, and the concentration of late-maturing varieties should be appropriately increased. If the concentration is too high, it will cause curling leaves and falling leaves. Ponkan orange leaves easily in autumn (October to November). Spraying 2,4-D10mg/L can reduce leaf shedding.The article is from the book "Application of plant growth regulators in fruit trees", and the content is for reference only.

These fertilizers are used in "minefields". How many have you stepped on?

Fertilizers play a huge role in promoting agricultural production and efficiency. Both chemical fertilizer, organic fertilizer and biological fertilizer have their own application mechanism. If used correctly, it will get twice the result with half the effort; Use the wrong way to get twice the result. In recent years, farmers tend not to pay attention to details in technology and use it based on experience. As a result, they have stepped into these misunderstandings step by stepAlert the "dark area" of biological fertilizer① In order to improve fertilizer efficiency, some farmers often mix biological fertilizer with fungicides, pesticides, herbicides, etc., which is easy to kill biological bacteria.Correct application method: if the application of bacterial fertilizer is inconsistent with the prevention of disease and insect pests and weeding, the bacterial fertilizer can be applied first, and then the weeding can be conducted after 48 hours. If seeds are mixed, do not mix them with seeds that have been mixed with fungicides. At the same time, it is also necessary to prevent mixing with uncooked farm manure, which will directly kill biological bacteria.② A large amount of high concentration chemicals mixed with chemical fertilizers have toxic effects on microorganisms in the bacterial fertilizer, especially when mixed with alkaline fertilizers such as ammonium bicarbonate and physiological alkaline fertilizers such as sodium nitrate, they can kill a large number of microorganisms in the bacterial fertilizer.Correct application method: For fields that have used chemical fertilizer for many years, biological bacterial fertilizer can not be applied in large quantities. Because crops are dependent on chemical fertilizer, biological bacterial fertilizer can not be used to replace nitrogen fertilizer at once. Therefore, its agent should replace 30%, 40% and 60% respectively in the first, second and third years. Phosphorus and potassium fertilizers can only be supplemented, not reduced.③ There are many kinds of bacterial fertilizer mixed with different kinds of bacterial fertilizer, and the active bacteria contained in them are different. It is not clear whether there is mutual resistance between them. If they resist each other, it will reduce the fertilizer efficiency.Correct application method: only one kind of biological bacteria fertilizer should be applied as far as possible. It is not suitable to apply multiple biological bacteria fertilizers containing different beneficial bacteria at the same time, and it is not necessary to change and apply different kinds of biological bacteria frequently.Do not enter the "deep water zone" of chemical fertilizer① Calcium magnesium phosphate fertilizer as topdressing calcium magnesium phosphate fertilizer is not easy to dissolve in water and the fertilizer effect is slow. As topdressing, especially after the middle period of crop growth, its utilization rate is low and the effect is poor.Correct application method: calcium magnesium phosphate fertilizer can only be used as base fertilizer and organic fertilizer, which is also good for seed dressing.② Direct seed dressing with superphosphate contains 3.5%~5% free acid, which is highly corrosive. Direct seed dressing will reduce the germination rate and seedling emergence rate of seeds.Correct application method: for topdressing, the furrow should be deep applied. As seed fertilizer, it should be applied 5~6 cm below or on the side of the seeds, and the fertilizer should be separated from the seeds with soil.③ Due to the serious "antagonistic effect" between zinc and phosphorus, the mixed application of zinc sulfate and superphosphate can largely inhibit the fertilizer effect of zinc sulfate and reduce its effectiveness.Correct application method: zinc fertilizer and phosphorus fertilizer should be applied separately. Phosphate fertilizer should be used as base fertilizer, zinc fertilizer as seedling fertilizer, or zinc fertilizer as base fertilizer, phosphorus fertilizer as seedling fertilizer, which can improve the fertilizer efficiency of phosphorus and zinc fertilizer.④ The "recrystallization" will occur soon after the borax is dissolved in the cold water, resulting in the precipitation of borax solution and the loss of fertilizer effect.Correct application: first put the boron fertilizer into a hot water bottle, add boiling water to dissolve it, close the bottle stopper and take it to the field, and then cool the water to the required concentration, the effect will be greatly improved.Beware of organic fertilizer "causing trouble"① Excessive application of burnable seedlings will cause a large accumulation of phosphorus, potassium and other nutrients in the soil, resulting in soil nutrient imbalance. At the same time, nitrate ion in the soil is gathered, which causes nitrate in crops to exceed the standard, and the concentration of soil solution is high, which is not conducive to root water absorption.Correct application method: The more organic fertilizer is applied, the better. Generally, 1000~1500 kg of green manure or 1000~1500 kg of green manure are applied per mu.② The combination of organic and inorganic fertilizers is not sufficient for the nutrient content of organic fertilizers, but the content is low. In the vigorous growth period of crops, the application alone cannot fully meet the nutrient requirements of crops.Correct application method: add an appropriate amount of ammonium carbonate or urea during application to adjust the carbon and nitrogen ratio and prevent the phenomenon of nitrogen competition between microorganisms and crops.③ The uncooked fertilizer is decomposed and fermented in the soil by microorganisms, and the ammonia gas produced is easy to cause crop root burning and poisoning, and some will also breed weeds and spread diseases and pests.The correct way to do this is to build a septic tank for fermentation, or pile up the compost and add water to wet it, and seal it with mud to make its temperature reach 35~40 ℃. After 25~30 days, the fermentation can be completed. The manure can be fully fermented at 60 ℃ to kill insect eggs and weed seeds, which is safer and more effective when used.The article is from "Rural · Agriculture · Farmers" by Li Shishi

A complete explanation of the control of wheat growth with chlormequat, paclobutrazol and chlorhexidine!

The exuberant growth of wheat before winter is characterized by the tender growth of wheat seedlings, more stems and too large leaf area coefficient before winter; The young spike differentiation process is advanced, and the serious year and plot jointing before winter.The harm of wheat growth1. Delay in the green period of wheatBefore winter, the flourishing wheat grows late and turns green slowly in early spring. The turning green period is generally delayed by 7 to 10 days, and the growth in early spring is obviously insufficient. The specific performance is that there are basically no spring new tillers in spring with late root spraying, few new roots and serious vigorous growth, which directly leads to the low rate of tillering and the reduction of ear number per mu.2. Wheat sheath blight and other diseases are seriously affectedBefore winter, the total number of flourishing stems is too large, the ventilation and light transmission in the population are poor, the humidity in the middle and lower parts is high, and the recurrent diseases such as sheath blight and powdery mildew in spring are relatively serious.3. Wheat is prone to lodgingBecause of the large population, insufficient illumination within the population, excessive elongation of basal internode, long length, thin stem wall, poor elasticity, and significant decline in wind disaster resistance, most of the pre-winter flourishing wheat is prone to lodging in the later stage.4. Weak root system of wheatThe above-ground and underground growth of flourishing wheat is out of balance, the underground root growth is weak, the number of roots is small, the soil is shallow, the vitality is poor, the water absorption function decays quickly at the late stage of filling, the ability to resist dry and hot wind is significantly reduced, and the phenomenon of premature aging is obvious.Causes of Wheat ProsperityPremature sowing will cause excessive accumulated temperature before winter, and it is easy to form vigorous seedlings before winter. The field performance is generally characterized by long and narrow leaves, drooping, and insufficient tillers. The young spike differentiation of the main stem and some large tillers before winter enters into the two-ridge stage.Too much sowing will lead to too large population before winter, which is easy to form flourishing seedlings. The field performance is generally crowded growth, poor individual development and few tillers.Excessive amount of fertilizer and water, especially excessive amount of nitrogen fertilizer, will also lead to growth before winter. In the field, there are many tillers, broad leaves and serious shade in the field.Variety reason: the flourishing seedlings formed by improper selection of varieties. Some spring and weak winter varieties are sown too early, which will also lead to vigorous growth before winter. This kind of flourishing seedlings are susceptible to freezing in winter.In addition, higher temperature and more rain before winter will also cause vigorous growth of wheat seedlings. If there are the above problems in the wheat field, we must pay attention to the control of prosperity, so as not to affect the subsequent growth of wheat, or even cause serious yield reduction!Why do winter wheat need chemical controlSave time and laborCommonly used physical control methods, such as repression and deep hoeing between lines, require large workload and time-consuming and labor-intensive.Chemical control can save time and labor, and get twice the result with half the effort. Wheat without herbicide before winter can be sprayed with the control agent.Quick and significant effectWhy do we have to control the chemical boom from turning green to the early stage of jointing?At present, the mechanism of good wheat control products on the market is mostly to make the wheat root strong and shorten the internode. Lay a good foundation for shaping the ideal plant type of wheat.The ideal plant type of wheat is: strong root system, short and thick internode at the bottom, good stem toughness, thin and long internode at the top, shaping the "pyramid" plant type, wide, thick and heavy leaves, good ventilation and light transmission, enhancing wheat photosynthesis, and achieving the purpose of resisting lodging and increasing yield.  Wheat internode shortening refers to reducing the distance between 1~3 internodes at the bottom of wheat.Early control will affect the green and jointing of wheat. The control is late. If the control is carried out after the jointing stage, the 1~3 internodes at the bottom of the wheat have grown and developed normally. The height of the internode at the bottom is fixed, and the re-contraction internode will shrink the middle internode, forming a thin upper and lower internode, and a thick middle internode. On the contrary, it is easier to collapse.Moreover, after the jointing stage, the wheat enters the booting stage, and the vegetative growth gradually changes to the reproductive growth. At this time, the re-chemical control affects the booting and heading of the wheat, and the heading of the irradiated wheat is slow, uneven or inconsistent, affecting the flowering and pollination, but affecting the wheat yield.It is often too late for many farmers to think of chemical control only when they have to see that after the wheat harvest, the wheat is growing seriously.Wheat control is not the shorter the wheat, the better!(Without a reasonable height of wheat, there is no potential for high yield!)In recent years, with the attention of the majority of farmers to the control of wheat boom, the use of chemical control of wheat boom has become more and more common, but now dealers, retailers and farmers also have some misunderstandings about the control of wheat boom:We blindly pursue the dwarfing effect of wheat. We believe that the shorter the height of wheat, the better the quality of wheat.In fact, the growth, development, flowering and fruiting of any crop require a large amount of nutrients. If the plant does not have a reasonable height and does not have sufficient accumulation of nutrients, it will cause a reduction in production. Therefore, the wheat control products are not the products that control the plant height as well as the good products. The good control products will promote the development of wheat roots, strong stems and better toughness while controlling the plant height, The stronger the lodging resistance of wheat. Good products are those that resist lodging and grow!Functional characteristics of chlormequat:Chlormethrin is an antagonist of gibberellin. After the use of Chlormethrin, it can effectively control plant growth, promote reproductive growth, shorten plant internode, grow short, strong, thick, developed root system, and resist lodging. At the same time, the leaf color is deepened, the leaf thickness is increased, the chlorophyll content is increased, and the photosynthesis is increased, so as to improve the fruit setting rate of some crops, improve the quality, and increase the yield.CCM can improve the water absorption capacity of roots, affect the accumulation of proline in plants, and help improve the plant's resistance to stress, such as drought, cold, saline-alkali and disease resistance. The chlormequat can enter the plant through leaves, young shoots, buds, roots and seeds, so it can be planted, sprayed and irrigated. Different application methods can be selected according to different crops to achieve better results.Use of chlormequat in wheat:Soak seeds with 0.3-0.5% liquid medicine for 6 hours, liquid medicine: seed=1:0.8, dry and sow; Spraying 2-3% liquid medicine on the seeds for seed dressing and sowing for 12 hours can strengthen the seedlings, make the roots developed, tiller early, tiller more, and increase the yield by about 12%. At the early stage of tillering, spray 0.15-0.25% liquid medicine at a rate of 50kg/mu (the concentration should not be higher, or the heading and ripening will be delayed). The wheat seedlings are short and healthy, with more tillers and an increase of 6.7-20.1%. Or spray at the end of tillering and at the beginning of jointing, which can effectively inhibit the elongation of 1-3 nodes at the lower part of the stem, which is extremely beneficial to prevent wheat lodging, and improve the earing rate. If sprayed at the jointing stage, it will not only inhibit the elongation of internode, but also affect the normal development of ear, resulting in reduced yield.Functional characteristics of paclobutrazol:As a plant growth regulator, paclobutrazol has the effects of delaying plant growth, inhibiting stem elongation, shortening internode, promoting plant tillering, increasing plant stress resistance, and improving yield. This product is applicable to rice, wheat, peanut, fruit tree, tobacco, rape, soybean, flowers, lawn and other crops, with remarkable effect.Use of paclobutrazol on wheat:At the turning green stage, spraying 30kg of 200mg/L liquid medicine per mu can make the plant dwarf, enhance the ability of lodging resistance, and can also cure wheat powdery mildew and improve the nitrogen absorption and utilization rate of the plant.Functional characteristics of methylpiperidine:Meperidium is a new plant growth regulator, which can be used in many crops and has many effects. It can promote plant development, flowering in advance, prevent falling off, increase yield, enhance chlorophyll synthesis, and inhibit the elongation of main stems and fruit branches. Spraying according to the dosage and different growth periods of the plant can adjust the plant growth, make the plant firm and resistant to lodging, improve the color and increase the yield.Meperidium is a plant growth regulator that seems to antagonize gibberellin. It is a plant growth regulator that seems to antagonize gibberellin and is used on cotton and other plants. In addition, the use of meperidium in winter wheat can prevent lodging; When used in apple, it can increase calcium absorption and reduce bitter depression; It can increase sugar content when used in citrus; Used for ornamental plants, it can inhibit plant overgrowth, make the plant firm, resist lodging and improve color; It can be used for tomatoes, melons and beans to increase yield and mature early.The principle of using meperidium (trimethylamine):The principle of spraying high instead of low, spraying strong instead of weak, spraying waterlogging instead of drought, spraying fertilizer instead of thin, small amount and many times.Use of acetaminophen on wheat:1. Seed mixing: use 4-5g, add 2.5kg of water, 5kg of wheat seeds, mix evenly, mix with the seeds, dry and sow.2. Jointing period: 10 grams per mu, 15 kilograms of water, spraying.3. Flowering period: use 10 grams per mu, mix 15 kilograms of water, and spray.

Application technology of paclobutrazol on peach and mango trees

Paclobutrazol is a highly active plant growth regulator, which has the effects of delaying plant growth, inhibiting stem elongation, shortening internode, promoting flower bud differentiation, increasing plant stress resistance, and improving yield. The application of paclobutrazol on fruit trees has obvious effect, the yield has increased significantly, and good economic benefits have been obtained.Application technology of paclobutrazol on peach trees1、 Inhibit the growth of new shootsSoil root application: when the peach bud germinates to 2cm long, apply the pesticide in the ring ditch at the root zone of each mature peach tree. The amount of pesticide applied to each tree can be 10-15g of 15% paclobutrazol wettable powder, which can effectively inhibit the growth of new shoots of peach trees, reduce the consumption of nutrients, significantly increase the number of flower buds, shorten its length, make the leaf color dark green, increase the chlorophyll content, and increase the dry matter of leaves. At the same time, it can improve the cold resistance of flower buds, improve the fruit setting rate, and significantly increase the yield. Due to the continuous absorption of the root system, soil application has a continuous inhibition effect. The dynamic fluctuation of the new shoot growth is small, and the inhibition effect on the new shoot growth of the peach tree in the year is obvious. The inhibition effect on the growth of the peach tree in the second year is large, and it begins to ease in the third year. High-dose treatment still had strong inhibition on new shoots in the third year. Soil application is prone to over-inhibition. The residual effect of soil application is long and will be stopped the next year.Leaf spraying: when the new shoots grow to 30 cm long, use paclobutrazol 1000~1500 mg/L to spray, the effective inhibition period is about 20 days, and then the inhibition is more moderate, and the growth dynamics of new shoots fluctuate greatly.Trunk smearing method: In the growing season or dormancy period, mix the paclobutrazol wettable powder with water in a small tea cup, and then smear it on the branches below the main branch with a small brush, with the same amount as soil application.Attention should be paid to the use of paclobutrazol: the dosage and concentration of paclobutrazol should be strictly controlled according to the local environment and peach varieties to avoid excessive inhibition of peach growth, and paclobutrazol should not be used for consecutive years.The application effect of paclobutrazol on fruit trees is obvious. A large-scale production experiment was carried out on 4-6-year-old mango trees. The results showed that the treatment flowered 12-75 days earlier than the control, and the amount of flowers was large, the flowering was neat, and the harvest period was also 14-59 days earlier, the yield was significantly increased, and good economic benefits were obtained.Paclobutrazol is a plant growth regulator with low toxicity and obvious effect, which is widely used at present. It can inhibit the biosynthesis of gibberellin in plants, thus inhibiting the vegetative growth of plants and promoting flowering and fruiting. Practice has proved that the growth of mango shoots can be effectively inhibited and flowering can be promoted by applying 10 grams of paclobutrazol (effective ingredient 15%) to each 3-4-year-old mango tree. In September 1999, the South Asian Tropical Crop Research Institute of the Chinese Academy of Tropical Agricultural Sciences applied 10 grams of commercial PP333 to the 3-year-old Tainong No. 1 and 4-year-old Aiwenmang and Zihuamang per tree soil, which increased the heading rate by 80.7% - 100% compared with the control (without PP333). The method of applying paclobutrazol is to dissolve paclobutrazol in water and evenly apply it in the ditch and cover it with soil after opening a shallow ditch in the tree crown drip line. If the weather is dry within 1 month after the application, the soil shall be properly watered to keep the soil moist.

"Two differences and one basis" for selecting plant growth regulators

Plant growth regulators have been used in agricultural production for many years. In general, they have played a significant role in regulating the normal growth of crops, coordinating the rational distribution of nutrients, and promoting crop yield and income. Many farmers can easily apply this new technology, which can make the slow growing crops recover quickly, and inhibit the vigorous growing crops to promote their stable growth. The growth and development of crops can be shaped according to people's wishes.However, in the process of selecting and using plant growth regulators, people often make mistakes and produce negative effects. Some will use promotive plant growth regulators on flourishing crops to make them flourish as they grow. Some of them use delayed plant growth regulators on normal growing crops, which inhibits the growth of crops. Some use a plant growth regulator at a time when it is not very sensitive to its crop development, and there is no response. Some increase the concentration of delayed plant growth regulators at will, resulting in the concentration of plant stems and leaves of crops, and long-term stiffness without hair. Some crops are forced to ripen by early application of ripening agents, which reduces both yield and quality.In order to prevent mistakes in the use of plant growth regulators, based on years of experience and lessons, the following points should be noted in the selection and application technology:1、 Difference1. Correctly identify and distinguish plant growth regulators(1) The product specification, standard number, production license, product registration certificate, period of validity, and factory name on the label of the selected regulator.(2) See if the supervision unit is authoritative.(3) See the effective dose, weight and application method.(4) Compare it with the genuine product to see if it is fake.(5) We should distinguish the difference between conditioner and micro-fertilizer. Some active fertilizers can also promote the early growth and early development of crops, but they mainly supplement nutrients and cannot replace plant growth regulators.2. Selecting plant growth regulators for different cropsDifferent crops have different sensitivity to plant growth regulators. For example, rice seedlings are sensitive to paclobutrazol. Hybrid rice is sensitive to gibberellin during seed production and flowering. The cotton seedling stage is sensitive to nitrophenol-potassium, and the bud and flowering stage is sensitive to the amine, the regulator and the auxin. Wheat seedlings were sensitive to chlormequat. Maize is sensitive to ethephon. Peanut is more sensitive than paclobutrazol. Soybean and tomato are sensitive to 2,4-D and lycopene. Fruit trees are sensitive to gibberellin and paclobutrazol. Do not indiscriminately abuse plant growth regulators in field production.2、 According to"One basis" is to select plant growth regulators according to the growth of crops. For example, when the flowering period of hybrid rice seed production is not met, gibberellin can be used to adjust the flowering period to close to the same, so as to improve the ear rate. If rice or peanuts grow vigorously at the seedling stage, use paclobutrazol to promote their strong and stable growth. If the cotton buds and bolls grow abnormally, a small number of times, light in the front and heavy in the back, can be used to spray chloramphenicol and auxilin. If the cotton bolls and stems are to be pulled out early, it is necessary to spray ethephon ripening agent in the range above 20 ℃ after the autumn peach is fully mature. For example, to prevent soybean and tomato from falling flowers and fruits, directional spraying of 2,4-D, lycopene and other regulators can be used. To prevent the lodging of wheat, we can spray chlormequat and chlormequat before jointing. Ethephon can be used to prevent maize lodging.(Source: China Fertilizer Information Network)