Soil improvement techniques for soybean cultivation

L. Soil conditions for high yield of soybean.

Soil condition is the basis of high yield of soybean. Soil water status, nutrient status and some physical properties of soil are important factors affecting soybean yield.

Soybean seeds need more water to germinate than cereal crops. The young roots of soybean are tender and have high water content, and the suitable soil moisture conditions can promote the young roots to grow in depth. The main root of the plant can reach about 1 meter, and the parallel expansion of the lateral root can reach about 0.5 meters. When the soil moisture is insufficient, it will affect its vertical and horizontal expansion growth.

Soybean roots are sensitive to changes in oxygen in the soil. Under the condition of hypoxia, the root growth decreased obviously. Therefore, moderate soil water content, deep plough layer and moderate tightness can provide good water content and aeration conditions, which will promote the growth and development of roots. In pedology, soil compactness is regarded as the physical property index of soil moisture and aeration in the soil plough layer, which is generally expressed by bulk density (grams per cubic centimeter of dry soil). The suitable soil capacity of soybean is 1.0 ~ 1.4. Loam is the most suitable for soybean growth, clayey loam, clay loam and sandy loam can also grow normally; sand and clay, weak water holding capacity or poor ventilation is not conducive to growth.

2. Soil preparation techniques such as turning over, ridge cultivation, raking stubble, deep loosening and other soil preparation techniques can be used to grow soybean.

(1) somersault. It is mostly used in spring soybean areas with one crop a year in the north. Through ploughing, soil ripening is accelerated, which is beneficial to the full utilization of nutrients. Create a certain depth of loose ploughing layer, burying agricultural fertilizer, stubble, diseases and insects, weeds and so on, so as to create conditions for improving sowing quality and seedling emergence.

The time of turning over varies with previous crops, and sometimes due to climatic conditions. Wheat stubble should be turned over in August, no later than the first ten days of September. The ploughing depth of black soil is 25cm to 35cm; loess, white serous soil, light alkaline soil or thin soil layer or subsoil containing harmful substances should not exceed the depth of fertile soil layer. After turning over, after waiting for the soil to fully accept Rain Water in the autumn, rake fine and flat. Corn stubble, millet stubble and sorghum stubble were turned in autumn. Autumn turn time is short, once it is rainy, it can not be carried out, can only wait for the following spring turn. Autumn turning should end before freezing, with a depth of up to 20cm to 25cm. Autumn ploughing should be raked immediately after ploughing, and raked and suppressed again before spring sowing in the following year to prevent soil moisture loss. It is appropriate to plough at a depth of 15 cm in spring.

Generally speaking, turning over in autumn is better than turning in autumn, which is beneficial to the soil storage of Rain Water; turning in autumn is better than turning in spring to prevent excessive loss of water before spring sowing. However, if the autumn turn is not appropriate, too much water, the formation of large clods, the effect is not as good as the spring turn.

(2) Ridge cultivation. It is a traditional tillage method commonly used in Northeast China to cultivate ridges after ploughing, which can increase the ground temperature, deepen the tillage layer and enhance the waterlogging and drought resistance. Before as corn, sorghum or millet, overwintering with the original ridge, before thawing in early spring, break the stubble pipe with heavy razor, then turn over the ridge and buckle the seed, and suppress the ridge platform with wooden rollers in time after turning the ridge to prevent soil moisture running.

(3) Harrow stubble. It is used in spring soybean area in Northeast China and summer soybean area in Huang-Huai River Basin. . raking stubble is a shallow ploughing method for flat soybeans. This method can prevent excessive ploughing from destroying soil structure, cause soil consolidation, and reduce the operating cost of deep ploughing machinery. In the northeast spring soybean area, rake stubble shallow ploughing is mainly used as the former plot. After the wheat harvest, use a double-row disc rake to kill the stubble, diagonally rake twice, and then sow again before sowing the following year. In the summer soybean area of the Huang-Huai River Basin, after the winter wheat was harvested, the bottom fertilizer was first applied, then the stubble was killed 2 times and 3 times with a disc rake, with a depth of 15 cm, and then a shallow rake with a light nail tooth rake was used to rake fine and flat before sowing.

(4) Deep pine. The subsoiling tillage method adopts mechanized operation with various methods and flexibility, so it is a promising tillage method. More than 80% of the farms with a high degree of mechanization in Heilongjiang Province have been adopted in soybean growing areas. The deep loosening shovel is used to loosen the soil without turning the soil layer, and the interval deep loosening is carried out, which breaks the plough bottom of the flat tillage method or ridge tillage method, and forms the plough layer structure with the coexistence of deficiency and reality. Ridge bottom deep loose depth is generally 15-20 cm, should not be too deep, ridge and ditch deep loose can be a little deep, generally up to 30 cm. At the same time, by means of deep loosening, topdressing, weeding and soil cultivation can be completed at the same time.