Li Dong: Winter rapeseed should be balanced and fertilized

On November 7th, it entered the winter season, and “living winter” means the beginning of winter. Before and after the winter in most parts of China, the precipitation decreased significantly, the air generally became dry and the soil lost more water. Therefore, for the winter wheat and winter rape planting areas, it is very important to protect against drought. The soil moisture condition has a very close relationship with the seedling growth and wintering of crops. Jiangxi Agricultural Reclamation Cloud: “Lidong rapeseed Xiaoxuemai”; all local farms have the idea of ​​“establishing winter, and cultivating the land to increase nutrients in the soil”.

Rapeseed is the only winter oil crop in China, and it is also a good place to raise land. It has a developed root system and secretes a large amount of organic acids, which can decompose and utilize the poorly soluble phosphorus in the soil. China is a big country in the production of winter rapeseed, which is widely distributed in the provinces of the Yangtze River and the Yunnan-Guizhou Plateau. Scientific fertilization is an important part of high yield, high quality and high efficiency of winter rapeseed. Rape is a crop that requires more fertilizer. It requires more nitrogen, phosphorus and potassium than rice, especially phosphorus and boron. For each 100kg of rapeseed, it needs to absorb 8-11kg of nitrogen, 3-5kg of phosphorus and 8.5-12.8kg of potassium. In the absence of nitrogen, the rape plants are short, with few branches and reduced yield. However, when the supply of nitrogen is too much, the protein in the grain will increase and the oil content will decrease; therefore, the nitrogen fertilizer should be applied reasonably. Only balanced fertilization can ensure that the yield and oil content of rapeseed are kept at a high level, while the partial application of nitrogen fertilizer causes the imbalance of nitrogen, phosphorus and potassium to significantly reduce the oil content of rapeseed. From the current production, the rational application of phosphorus, potassium and boron fertilizer can improve the oil content of rapeseed and improve the fatty acid properties in the oil.

About the dosage and ratio of ingredients for balanced fertilization of rapeseed. Under the premise of making full use of organic fertilizer, the application of NPK fertilizer according to soil fertility level and yield target is mainly to control the amount of nitrogen fertilizer and increase the application of phosphorus and potassium fertilizer. Taking the nutrient management advice in rapeseed production in Hubei Province as an example, the recommended amount of NPK fertilizer is as follows: the yield level is above 200 kg/mu: the recommended application of nitrogen fertilizer (pure N) 11-13 kg/mu, phosphate fertilizer (pure P2O5) 4~ 6 kg / mu, potash fertilizer (pure K2O) 7 ~ 9 kg / mu, borax 1.0 kg / mu; production level 100 ~ 200 kg / mu: nitrogen fertilizer (N) 8 ~ 10 kg / mu, phosphate fertilizer (P2O5) 3 ~ 5 Kg/mu, potash fertilizer (K2O) 5-7 kg/mu, borax 0.75 kg/mu.

In the fertilization period, due to the long growth period of rapeseed, the application of nitrogen fertilizer and potassium fertilizer can increase the utilization rate. To this end, the number of fertilizations should be increased appropriately. In addition to the base fertilizer, wintering fertilizer, bud fertilizer and flower fertilizer should be applied. For the live broadcast and intercropping rapeseed, it is necessary to increase the fertilization fertilizer in winter. The fractional application of nitrogen and potassium fertilizers should appropriately reduce the amount of base fertilizer and increase the proportion of application in the growth period. Specific fertilization period: for transplanting rapeseed: 60% of the total amount of nitrogen and potassium fertilizer is applied as base fertilizer, 20% is used as wax fertilizer (50 days after transplanting), 20% is used as fertilizer (80 days after transplanting); Rapeseed: 40% of total nitrogen fertilizer is applied as base fertilizer, 30% is used for seedling fertilizer (25-30 days after sowing), 15% is used as wax fertilizer (about 80 days after sowing), and 15% is used for manure (110 after sowing) Around day), 60% of the total potassium fertilizer is used as base fertilizer, 30% is used as wax fertilizer (about 80 days after sowing), 10% is used as fertilizer (about 110 days after sowing), and the remaining fertilizer is used as base fertilizer.

There is an important problem in current production, and the base fertilizer should be applied in depth to promote the growth of rapeseed roots.

Taking live rapeseed as an example, it has obvious main roots, and the lateral roots are distributed along the main roots in various layers of the soil, and the lateral roots are not developed enough. If the fertilizer is applied only to the surface of the soil, the root system (including the main root) of the rapeseed will be guided only longer than the surface layer of the soil without deep ties, forming a “floating root”, which will result in the unstable rooting of the rapeseed, the ability to absorb soil water and fertilizer, and the tendency to fall into the seedlings and take off. Fertilization, drought and other phenomena. During the growth of winter rapeseed, various natural disasters or harsh conditions are often encountered, such as the snowstorm in early 2008, the drought in early 2009, and the unfavorable factors such as spring rain and windy when rapeseed blooms every year. In the rainy weather, this is a limiting factor for the production of rapeseed in China.

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