How to Grow High-Yield Soybeans? A Detailed Guide to the "Four Changes and One Addition" Cultivation Technique

Traditional drill sowing of soybeans results in narrow rows and overcrowding, and along with various other factors, yields have long hovered around 100-150 kg. Through years of experimental research, we have developed a new approach that can increase soybean yields by more than 40%, namely the "Four Changes and One Addition" technique.

The usual measures for increasing soybean yields include, besides selecting new high-quality, high-yield varieties, paying attention to crop rotation. According to experiments, after years of continuous cropping, soybeans show slow growth, short plants, yellowing lower leaves, early leaf drop, and few pods with small seeds. Experiments have also proven that continuous cropping (monocropping) for more than 3 years can reduce yields by 20%-30%, and 2 years of back-to-back continuous cropping can reduce yields by more than 30%. Therefore, crop rotation plays an important role in soybean production. To achieve high-yield and ultra-high-yield soybean cultivation, the "Four Changes and One Addition" new cultivation technique should be implemented on this basis.

1. Change traditional narrow-row drill sowing to wide rows of 40-45 cm

First, it facilitates ventilation and light penetration, reduces field crowding, prevents soybean flower and pod drop, and provides favorable space and conditions for normal soybean growth. Second, it is easier to manage. In areas accustomed to drill sowing, the middle leg of the drill can be blocked to increase row spacing, which saves labor and seeds, and lays the foundation for thinning and spacing, making field management more convenient.

2. Change traditional no-thinning to single-plant equidistant rational close planting

In most areas, soybean production management is relatively extensive, with no habit of thinning. Density is often too high, causing field crowding, flower and pod drop, and reduced yields. The density should be determined according to different plots, sowing times, and different varieties. Specifically: fertile land should be sparser, lean land denser; early sowing sparser, late sowing denser; spring sowing sparser, summer sowing denser; large-leaf types with many spreading branches sparser, small-leaf types with few compact branches denser; late-maturing varieties sparser, early-maturing varieties denser. For example, for varieties widely planted in the Lunan region such as Ludou No. 2, Gaofeng No. 1, 84-5, Ludou No. 4, and Zaoshu No. 1, the summer sowing density is 14,000-20,000 plants per mu, with row spacing of 40 cm and plant spacing of 8-10 cm.

3. Change no fertilization to applying seed fertilizer and nitrogen fertilizer at flowering and pod-setting stages

For many years, most farmers have not had the habit of fertilizing soybeans. According to our experiments, applying seed fertilizer diammonium phosphate at 10-15 kg per mu to soybeans, deeply applied at sowing; topdressing pure nitrogen at 2-3 kg per mu of nitrogen fertilizer at the flowering and pod-setting stage; starting from soybean flowering, combined with other agents, foliar spraying of 0.3%-0.5% potassium dihydrogen phosphate, once every 10 days, can achieve a yield increase of 20%-30%.

4. Change no irrigation to timely irrigation of pod-filling water

The proverb "When soybeans flower, go catch fish and shrimp" indicates that soybeans need a large amount of water during the three periods of flowering, pod-setting, and pod-filling. Sufficient water at this time can reduce flower and pod drop, increase pods, increase seeds, and improve seed weight. From late August to September, most years are relatively dry. According to our experiments, timely irrigation can increase yields by more than 10%-25%, or even 30%-50%.

5. Increase the application of plant growth regulators

During the flowering, pod-setting, and pod-filling stages of soybeans, scientific use of plant growth regulators has a significant effect on pod-filling and increasing seed weight. In areas where growth is not luxuriant, at full bloom, dissolve 0.001 g of yield-increasing agent in a small amount of alcohol, add 35-100 kg of water, spray 60 kg per mu, and spray again after 7 days, which can increase flowers and preserve pods and improve 100-seed weight; or use triacontanol at a concentration of 0.1 mg/kg, sprayed in 2 applications. At early flowering, plants are smaller, so spray 20 kg per mu; at full bloom, plants are larger, so spray 40 kg per mu. In fields with high fertilizer and water cultivation, at the early flowering stage of soybeans, use 0.125% chlormequat, spraying 30 kg per mu, generally increasing yields by 10%-20%. In fields with severe lodging due to tall stalks, using chlormequat can increase yields by more than 30%. However, special attention should be paid: many plant growth regulators have different effects on crop physiological regulation at different concentrations, and improper use can be counterproductive. Therefore, special attention should be paid to concentration ratios during use.