Field Management techniques of Brassica napus after Spring

After the beginning of spring, with the gradual increase of air temperature, the vegetative growth and reproductive growth of rape gradually entered a prosperous period, the main stem increased rapidly, branches appeared continuously, short-stalked leaves, sessile leaves and branched leaves were all born in this period, and a large number of buds differentiated. It's the fastest growing period in a lifetime. Therefore, it is suggested that farmers should strengthen the field management in this period to promote the normal growth and development of rape. 1. Apply fertilizer scientifically. Rape grows vigorously after spring. In order to promote high yield, attention should be paid to the rational application of fertilizer. Generally speaking, when the height of rape bolts is about 10 cm, proper fertilization should be applied according to the situation. The fields with poor growth can apply 5 kg urea per mu or 10 kilograms of human and animal manure per mu, so as to increase the number of effective branches, horns and grains per plant and ensure the steady growth of rape in the later stage. In the early bolting stage and early flowering stage, on the basis of applying boron fertilizer to the base fertilizer, the concentration of 0.1% 0.2% borax solution should be sprayed on the leaf surface, respectively, so as to prevent boron deficiency from causing flower sterility, resulting in serious yield reduction, decrease in oil content of rapeseed and deterioration of quality. From the beginning to the full flowering stage, combined with spraying boron fertilizer with a concentration of 0.2% potassium dihydrogen phosphate solution per mu, pod shedding and shade angle can be effectively reduced and grain weight can be increased. 2. Drainage and waterproofing. It is necessary to clean up the three ditches in the field in time after spring, while deepening the ditches outside the field, keeping the ditches connected and draining smoothly, which can drain the stagnant water in the field and reduce the soil moisture, so as to ensure the normal growth and maturity of rape in the soil with suitable water content, prevent the lower leaves from dying prematurely, improve the disease resistance of rape and obtain higher yield. 3. Prevention and control of diseases. There are few insect pests in rape in late spring, mainly to prevent Sclerotinia sclerotiorum. The disease is harmful to rape, light reduces the number of pods, grains, grain weight decreases, heavy plants wither early, or even no harvest, generally can lead to a yield reduction of about 15%, serious up to more than 40%. The disease can occur from seedling stage to mature stage, and the disease is the most common after flowering stage. Leaves, stems, branches, petals, pods and seeds can all occur. The prevention and control of the disease should be based on strengthening ditch drainage, reducing soil and field humidity, removing old yellow and diseased leaves in batches at full flowering, improving field ventilation and light transmission, controlling the spread of bacteria and reducing the source of bacteria. The full flowering stage is the key period for field spraying control. The fields with good growth should be sprayed once with 40% sclerotia net 1000 Mu and 1500 times per mu at the early flowering stage and at the full flowering stage, and 1500 times with 70% Topurazine wettable powder per mu at the final flowering stage to ensure the control effect. 4. harvest at the right time. Rapeseed harvested too early, light grain weight, low oil content, high yield can not harvest. If harvested too late, it is easy to split the fruit and drop grains, resulting in loss. When all the pods of the main inflorescence are yellow, 70% of the pods of the whole plant and the whole field turn green and yellow, the pods of the lower part of the main inflorescence are yellow and glossy, and the seeds show the inherent color of this variety. Should take advantage of the morning dew is not dry or cloudy harvest, pay attention to cut gently, reduce the loss. If it is sunny, after drying the water, the plants can be stacked and ripened for 7 days, and then spread and dried and threshed, so as to promote the ripening of some green fruits, full grains, and increase the yield and oil content of rapeseed. If the continuous rain can not be threshed in time, then tie the rape into a handful, pods up, vertical discharge, avoid stacking, causing fever, mildew and sprouting, affecting the quality of rapeseed.