Key Techniques for Mechanized High-Yield Cultivation of Densely Planted Soybean

The integrated mechanized high-yield cultivation technique for densely planted soybean is based on the three-ridge soybean cultivation technique, while continuing to maintain deep loosening, layered deep fertilization, and precision sowing. It draws on foreign experience in narrow-row dense planting and semi-dwarf varieties for increasing yields, and combines these with matching machinery to form an integrated mechanized high-yield cultivation technique, including flat-planting dense planting technology and small-ridge dense planting technology.

I. Technical advantages

1. Reasonable dense planting increases yield. The technical feature is reasonable dense planting, uniform crop distribution, and increased crop photosynthesis. Select lodging-resistant semi-dwarf varieties, increase the number of retained seedlings per hectare by one quarter, increase yield by 20%, and increase yield by about 50 kg per mu.

2. Deep loosening stores water and conserves soil moisture. After deep loosening, the soil increases its capacity to store water and conserve moisture, breaks through the plow pan, establishes an underground reservoir, can accept a large amount of rainwater, prevents surface runoff, prevents soil erosion, increases the depth of the plow layer, and improves the soil.

3. Autumn soil preparation provides good soil moisture and is beneficial for spring sowing. After deep loosening, rotary tillage and leveling and fine harrowing are carried out to reach a ready-to-sow state, preventing soil moisture evaporation and ensuring full seedling emergence from a single sowing.

4. Reduce operation costs. One deep loosening can last for three consecutive years of planting. Each year only one rotary tillage, precision sowing, and mechanical closed weeding are needed, which can reduce production costs. Reducing the number of times tractors enter the field can improve soil structure, reduce soil bulk density, and create a good environment for soybean growth.

II. Technical requirements

1. Tillage and soil preparation requirements. For deep loosening and soil preparation, the ISQ-350 all-direction deep loosener is mainly used for deep loosening, with a deep loosening depth of more than 35 cm. After deep loosening, mechanical rotary tillage and stubble removal are used for soil preparation; soybean stubble can be directly rotary tilled. It is required to level and finely harrow to reach a ready-to-sow state. Never deep loosen in autumn and rotary till in spring, which causes moisture evaporation and loss. As a remedial measure when there has been no deep loosening, use a chisel deep loosener before sowing, and immediately carry out rotary tillage, sowing, and compaction after deep loosening to prevent moisture loss.

2. Variety selection and treatment. Kenjiandou 23 can be selected as the main variety, with Hefeng 42 and Dongnong 10 as companion varieties. Semi-dwarf varieties suitable for dense planting and resistant to lodging should be selected. After seed selection to remove impurities, diseased seeds, and insect-damaged seeds, the purity should be no less than 98%, and the germination rate no less than 95%. Seed dressing treatment with seed coating agent is used. ND special soybean seed coating agent produced by Heilongjiang Bayi Agricultural University can be used, with a dosage of 1%-1.5% of the seed. A coating machine can be used for coating; manual coating must be complete and uniform.

3. Fertilization requirements: the fertilizer amount per hectare is 240 kg-320 kg, including: diammonium 150 kg-200 kg, urea 40 kg-60 kg (including 20 kg for topdressing), and potassium sulfate 50 kg-60 kg. Apply at the same time as sowing, in layered deep application. The first layer is 4-6 cm below the seed, and the second layer is 8-12 cm below the seed. Where conditions permit, apply one ton of organic fertilizer per mu, evenly spread on the soil surface before autumn soil preparation. It is best to use soil testing and formula fertilization, with the total fertilizer amount increased by more than 15% compared with conventional planting methods. Topdressing is carried out by foliar spraying at the early flowering stage and seed-filling stage, with each application per hectare using 10 kg urea + 200 g boron-molybdenum fertilizer or 150 g ammonium molybdate.

4. Sowing requirements: begin sowing when the temperature steadily passes 7-8°C. Sowing generally starts on May 5, and the sowing period must not exceed the 15th. A delayed sowing period results in late emergence, underdeveloped crop root systems, shallow rooting, and easy lodging. The sowing method is flat planting, with a row spacing of 45 cm, plant spacing of 11-12 cm, and about 360,000-400,000 retained seedlings per ha. Sowing depth is 3-5 cm. Compact in time after sowing to prevent moisture loss.

5. Chemical weeding: carry out closed weeding between after sowing and three days before emergence, with a water dilution amount of 225-450 kg per hectare. Use a small four-wheel tractor with a small sprayer for the operation.

The herbicide formulas and amounts per hectare are as follows:

1) 50% acetochlor 2.5 kg + 80% kuocaoxing 60 g mixed and sprayed.

2) 50% acetochlor + 70% saike 300-600 g mixed and sprayed.

3) 90% henaishi 2 kg + 20% douhuanglong 150 g mixed and sprayed.

6. Field management: from the early flowering stage to the full flowering stage of soybean, the crop growth must be observed. If growth is excessive, paclobutrazol or soybean fengshoubao and other chemical control agents can be sprayed to preserve flowers and pods and prevent lodging. In early August, depending on the weed situation, carry out one manual removal of large weeds.

7. Harvest: carry out at the yellow-ripe stage. A small four-wheel tractor with a windrower can be used for segmented harvesting, followed by concentrated threshing. At the full-ripe stage, a large combined crawler low-cutting device can be used for direct harvesting, with stubble height lower than 6 cm, comprehensive loss rate less than 3%, muddy grain surface less than 5%, and cleanliness rate greater than 95%.