Key Points of High-Yield Cultivation Techniques for Direct-Seeded Soybean after Wheat Harvest

The Longkou City Agricultural Technology Promotion Center conducted a two-year study on summer direct-seeded soybean after wheat harvest. The experiment used the Ludou 11 variety, and the yield per 667 sq m reached more than 300 kg. Through the experiment, @#@245@#@-soybean direct seeding method replaced the wheat-corn relay intercropping model, with a significant increase in benefits, raising income by more than 400 yuan per 667 sq m. The key techniques are early seeding by rushing the stubble, single-seed sowing, density control, and timely harvest.

1. Variety selection and treatment. Select varieties with stiff stems that do not lodge, disease resistance, and high yield suitable for high-yield cultivation, such as Ludou 11, 99-5, etc. Before sowing, carry out mechanical or manual selection, removing broken seeds, diseased-spot seeds, insect-eaten seeds, green and shriveled seeds, and other impurities. After selection, the seeds should reach Grade 2 improved variety or above, with purity above 99%, cleanliness of 99%, germination rate above 95%, and moisture content no higher than 13%.

2. Sowing. The wheat harvest period in Longkou City is around June 20, so soybean should be sown early by taking advantage of soil moisture before June 25. High-yield fields should be sown before June 20 as much as possible. Direct seeding can be used, or after stubble clearing with a stubble-clearing machine, manual or mechanical sowing can be used, adopting the single-seed sowing method. When soil moisture is not ideal, irrigation after sowing can be adopted to ensure full emergence in one sowing. Control the density well and improve population uniformity. Adopt the single-seed sowing method, and after sowing carry out thinning, final singling, and rational close planting. For plains with fertile soil and deeper soil layers, the plant number per 667 sq m should be controlled at 6500-7500 plants; for mountainous and hilly areas with thinner soil and shallower soil layers, the plant number per 667 sq m should be controlled at 7500-9500 plants. Sowing depth is 2-4 cm.

3. Field management. Soybean is a crop with relatively high water demand, so irrigate when drought occurs. Generally, before branching and early flowering, apply fertilizer according to soil fertility and seedling growth conditions. For high-yield fields with wheat yield above 500 kg per 667 sq m, nitrogen fertilizer may be omitted, and only phosphorus and potassium fertilizers applied; for plots with poorer soil fertility, apply 6-7 kg of diammonium phosphate, 4-5 kg of urea, and 3-4 kg of potassium fertilizer per 667 sq m, or use 13-15 kg of soybean special fertilizer, applied in furrows. Early control of soybean aphids is an effective method to prevent viral disease. Generally, at the early stage of disease occurrence, spray with 10% imidacloprid at 2500 times dilution. After sowing, evenly spray the soil surface with acetochlor.

4. Timely harvest. The best harvest time for soybean is when only 2-3 yellow-white leaves remain on the upper part of the plant. At this time, the nutrients in the plant have completely flowed back into the seeds, and at harvest the seeds are plump and the 1000-grain weight is high.