Characteristics and principles of fertilizer requirement for winter wheat to improve fertilization technology

winter wheat

Winter wheat is sown in autumn and harvested in summer after low temperature vernalization. The general field yield is 300~600 kg, among which the high yield level is above 400 kg; the growth period is long, mainly including different stages such as seedling emergence, tillering, rejuvenation, rising, jointing, booting, flowering and maturity. The characteristics of fertilizer requirement, fertilization principles and fertilization techniques are as follows:

1. Characteristics of fertilizer requirements

1. The key stage of topdressing is from rising to jointing. The nutrient uptake capacity was weak in seedling stage (from seedling stage to re-greening stage), and the cumulative uptake of N, P and K was less than 10% of the total uptake amount in tillering stage, but the nutrient uptake capacity in booting stage (from re-greening to heading stage) was over 75% of the total uptake amount, which was the peak of nutrient uptake. About half of these nutrients come from fertilizer, among which phosphorus and potassium mainly depend on basal fertilizer, nitrogen fertilizer pays equal attention to basal and topdressing, and topdressing is mainly nitrogen, so rising to jointing is the key period of nitrogen topdressing.

2. Fertilization at tillering stage is affected by many factors. Wheat is a tiller crop per plant, the effective panicles per mu are closely related to the yield per mu, but the tillering stage is sensitive to nitrogen fertilizer, and excessive application is easy to cause ineffective tillering increase and plant lodging. The growth and tillering of wheat are also related to variety characteristics, sowing quantity, sowing quality, soil fertility and moisture content, climate conditions and other factors. Therefore spring soil fertility, moisture, seedling and other specific conditions, determine the amount of nitrogen and fertilizer application period and comprehensive management.

3, crop rotation fertilization should be given consideration to two crops. Winter wheat and summer corn crop rotation, fertilization should consider the characteristics of rotation fertilization, two crops as a whole: nitrogen application amount of the two crops is roughly equal, but phosphorus fertilizer should be mainly applied to winter wheat, potassium fertilizer should be mainly applied to summer corn.

II. Principles of Fertilization

1. Improve fertilization technology. Advocates to increase the application of organic fertilizer, implement straw return to the field, organic fertilizer and inorganic fertilizer should be applied in combination; adhere to the fertilization policy of "appropriate nitrogen, stable phosphorus, supplement micro", appropriately reduce the total amount of nitrogen fertilizer, adjust the proportion of nitrogen fertilizer base and top-up, reduce the amount of nitrogen fertilizer in the early stage, nitrogen fertilizer should be applied in different times; according to the characteristics of seedlings, moisture and different wheat areas, adopt different comprehensive management measures of water and fertilizer. The total number of stems per mu should be controlled between 600,000 and 800,000, and fertilizer should be applied according to seedling classification. For the weak seedling field with total stem number less than 450,000, it is necessary to give priority to promotion, top fertilizer should be applied early to the re-greening and rising stage, and the amount of nitrogen fertilizer should be increased appropriately; for the vigorous seedling field with total stem number more than 800,000, top fertilizer should be applied after jointing, and the amount of nitrogen fertilizer should be reduced appropriately.

2. Strengthen comprehensive management. According to local climate characteristics and fertilization conditions, select varieties that can grow normally and mature, have high ear formation rate and strong stress resistance; screen seeds before sowing, sun-seed, disinfect seeds, etc.; sow at appropriate time and in appropriate amount, improve soil preparation and sowing quality; manage before winter and returning green period, irrigate winter water in northern winter wheat area, irrigate and fertilize according to seedling condition, soil moisture and soil fertility; winter wheat is the key period for fertilization from rising to heading, and classified management shall be carried out according to seedling condition; After heading, moderate irrigation and foliar fertilizer should be sprayed to prevent premature senescence of wheat, increase grain weight and control powdery mildew, rust, aphid, sticky insect, midge and other diseases and insect pests.

III. Fertilization techniques

① Nutrient application rate. Total fertilizer application per mu: N 12 ~15 kg, P 2O 56~8 kg, K 2O 4~8 kg.

(2) Fertilizer application rate. Base fertilizer: It is recommended to apply organic fertilizer, such as 1500~2000 kg of decomposed farm manure, 6~8 kg of urea or 20~25 kg of ammonium bicarbonate, 15~20 kg of diammonium phosphate or 40~50 kg of calcium superphosphate and 5~10 kg of potassium chloride per mu; if compound fertilizer is used, it is appropriate to select medium nitrogen, high phosphorus and low potassium type in Huanghuaihai Plain, such as 15-20-10 or 16-20-18; In the Yangtze River Basin, it is advisable to select universal compound fertilizers with equal or similar nitrogen, phosphorus and potassium contents, such as 15-15-15 or 12-15-18, etc., with an application rate of 30 - 40 kg per mu. Topdressing: apply urea 15~20 kg per mu from returning green to jointing stage, once or twice. For strong gluten and high quality wheat, 3~5 kg urea can be added at flowering stage.