New High-Yield Cultivation Technique for Soybeans: "Four Changes and One Addition"

With the traditional tillage and sowing method for growing soybeans, the rows are narrow and the plants too dense, and combined with various other reasons, yields have long hovered around 100-150 kg. Through years of experimental research, we have worked out a new approach that can increase soybean yields by more than 40%, namely the "Four Changes and One Addition" technique.

The usual measures for raising soybean yields, besides selecting new high-quality, high-yield varieties, also include paying attention to crop rotation. According to experiments, after many 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%, or even more, and 2 years of continuous cropping following a one-year break can reduce yields by more than 30%. Therefore, crop rotation and changing to a different crop are of great significance in soybean production. To achieve high-yield and super-high-yield soybean cultivation, the new "Four Changes and One Addition" cultivation technique should be implemented on this basis. The specific methods of "Four Changes and One Addition" are:

One: Change the narrow rows of traditional drill sowing to wide rows

Changing the narrow rows of traditional drill sowing to wide rows of 40-45 cm helps with ventilation and light penetration, reduces field crowding, prevents soybean flower and pod drop, and provides favorable space and conditions for normal soybean growth; it is easy to work with, and in places accustomed to drill sowing, the middle leg of the drill can be blocked to increase row spacing, which saves labor and seed, and lays the foundation for thinning and setting plants, making field management easier.

Two: 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 seedlings, often resulting in excessive density, field crowding, flower and pod drop, and reduced yields. The degree of density should be determined according to different plots, sowing times and different varieties. Specifically: fertile land should be sparse, lean land should be dense; early sowing should be sparse, late sowing should be dense; spring sowing should be sparse, summer sowing should be dense; varieties with large leaves and many spreading branches should be sparse, while those with small leaves and few compact branches should be dense; late-maturing varieties should be sparse, early-maturing varieties should be dense. For example, in the southern Shandong region, varieties grown on a relatively large area such as Ludou No. 2, Gaofeng No. 1, 84-5, Ludou No. 4, and Zaoshu No. 1 have a summer sowing density of 14,000-20,000 plants/667 sq m, with a row spacing of 40 cm and a plant spacing of 8-10 cm.

Three: Change no fertilization to applying seed fertilizer and nitrogen fertilizer at the flowering and pod-setting stages

For many years, most farmers have not had the habit of fertilizing when growing soybeans. According to our experiments, applying seed fertilizer diammonium phosphate (10-15 kg/667 sq m) to soybeans, deeply applied at sowing; topdressing nitrogen fertilizer at the flowering and pod-setting stages at a rate of 2-3 kg pure nitrogen/667 sq m; and from the start of soybean flowering, spraying the leaves with 0.3%-0.5% monopotassium phosphate together with other chemicals, once every 10 d, can achieve a yield increase of 20%-30%.

Four: Change no watering to timely watering at the seed-filling stage

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

Five: Increase the application of plant growth regulators

During the flowering, pod-setting and seed-filling stages of soybeans, the scientific use of plant growth regulators has a clear effect on seed filling and increasing seed weight. Zengchanling, triacontanol and others are hormone substances that promote soybean growth, while chlormequat and others are substances that inhibit soybean growth. Their correct use can effectively increase soybean yields. The methods of use are as follows: Zengchanling can dissolve in water or alcohol. In places where growth is not luxuriant, at full bloom, dissolve 0.001 g Zengchanling in a small amount of alcohol, add 35-100 kg water, spray 60 kg per 667 sq m, and spray again after 7 d; this can increase flowers and preserve pods and raise 100-seed weight. Or use triacontanol at a concentration of 0.1 mg/kg, sprayed twice: at early flowering the plants are smaller, so spray 20 kg per 667 sq m, and at full bloom the plants are larger, so spray 40 kg per 667 sq m.

In high-yield and super-high-yield soybean cultivation, because of relatively large amounts of fertilizer and water, soybeans can grow too luxuriantly, and lodging in the later stage often causes flower and pod drop, preventing high yields. Using chlormequat can prevent lodging caused by excessive vegetative growth, play a role in preserving flowers and promoting pods, and increase yields very significantly. The method of use is: in fields cultivated with high fertilizer and water, at the early flowering stage of soybeans, use 0.125% chlormequat and spray 30 kg per 667 sq m, generally increasing yields by 10%-20%; in fields with tall stalks and severe lodging, using chlormequat can increase yields by more than 30%. However, special attention must be paid: many plant growth regulators have different effects on crop physiological regulation at different concentrations, and improper use can backfire. Therefore, during use, special attention should be paid to the concentration ratio.