Cultivation Technique And Effect On Soil Fertility Of Oilseed Rape Planting As Green Manure

Green manure can not only provide nutrients for the crops, but also improve soil fertility. The traditional green manure crops in China are mainly nitrogen-fixing legume, such as milk vetch, etc. Cultivation and application of oilseed rape as a new type of green manure in our country is not very common. Field experiments were conducted to study the appropriate amount of sowing, sowing date and the optimum fertilizer application rate of oilseed rape as green manure planting, and to explore the effects of different amounts of oilseed rape plowing on soil nutrient content, early rice and late rice production. The results were to provide theoretical bases for the popularized and applications of oilseed rape as green manure. The main results are as follows:1. Effect of cultivation mode on fresh weight of oilseed rapeSowing rate, sowing date and fertilizer application rate had a significant effect on the fresh weight of oilseed rape. The fresh weight increased with increasing of rape seed rate in a small amount of sowing. The fresh weight began to stabilize in a big amount of sowing. When the seeding rate was7.5kg/hm2and11.25kg/hm2, the growth rate of yield was both26%, compared to3.75kg/hm2. When sowing time was over the best time, fresh yield had a significantly reduced in this experiment. The fresh yield of oilseed rape decreased6153kg/hm2when sowing time delayed10days. The fresh weight of oilseed rape increased significantly with increasing fertilizer application rate. The fresh weight of oilseed rape in the treatment of N135P67.5was significantly higher than the treatments of N45P22.5and N90P45. Compared with CK, the increase of fresh weight was4337-15275kg/hm2, the growth rate of yield was61%-216%. In conclusion, the optimum seeding rate was7.5kg/hm2, the appropriate sowing date was before November20and the suitable fertilizer rate was N90P45.2. Effect of nitrogen and phosphorus fertilization rate on the nutrient content of oilseed rapeNitrogen and phosphorus fertilization rate had a significant effect on the content of nitrogen, phosphorus and potassium of oilseed rape. The content of nitrogen, phosphorus in those fertilizer application treatments were significantly higher than the treatment of CK. The highest increase in nitrogen content of dry oilseed rape was1.65mg/g, the highest increase in phosphorus content was0.33mg/g. The nitrogen, phosphorus and potassium accumulation of dry oilseed rape gradually increased with the increasing nitrogen and phosphorus fertilization rate. The highest accumulation of nitrogen, phosphorus and potassium was21.88kg/hm2,8.84kg/hm2and40.47kg/hm2.3. Effect of oilseed rape plowing on soil nutrient contentThe amount of oilseed rape plowing had a significant effect on soil nutrient content. Oilseed rape plowing significantly increased the content of organic matter, the highest increase content was1.23g/kg, the growth rate was up to13%. When the amount of plowing was30000kg/hm2, the total nitrogen in soil reached a maximum1.51g/kg, the growth rate was73%. As the amount of oilseed rape plowing increased, the Alkali-N in soil was gradually increased. When the amount of plowing was45000kg/hm2, the content of soil Alkali-N was significantly higher than other plowing treatments and CK. The content of Olsen-P and Available K increased with the increasing of the amount of plowing. As the amount of oilseed rape plowing increased, the pH value increased at first and then decreased. When the amount of plowing was15000kg/hm2, the pH value reached a maximum5.50.4. Effect of oilseed rape plowing on early rice and late rice productionThe early rice yield had a significantly increased with different amount of oilseed rape plowing. As the amount of oilseed rape plowing increased, early rice yield had a increasing trend. Compared with CK, the increase of the early rice yield was450～765kg/hm2, the growth rate of yield was6%-9%.The effect of oilseed rape on late rice yield was also significantly. Compared with CK, the increase of the late rice yield was390～975kg/hm2, the growth rate of yield was2.4%-10%. Considering the cost and convenience of operating, we recommended the amount of oilseed rape plowing was30000kg/hm2.