Influence of green manure embedding methods on agrophysical characteristics of soil fertility and soybean yield of the Debyut variety in the Amur Region

Abstract

The key importance in the system of soil fertility reproduction belongs to the return of nutrients and energy to the soil compensating for their removal with harvested crops. Under the current conditions, the use of biological methods for increasing soil fertility becomes particularly relevant. Green manuring is among the most efficient biological methods. An important role in the implementation of this method is assigned to agronomic practices used to incorporate green manure biomass. The research findings on the effect of different methods of green manure incorporation on soil agrophysical characteristics and the yield of the soybean variety Debyut under the conditions of the Amur Region are discussed. Field experiments were conducted in 2024 and 2025 on floodplain soils (Kovrizhka village, Konstantinovskiy Municipal District). The experimental design included three variants of green manure incorporation: disking to a depth of 6-8 cm (BDM-7); disking to a depth of 18-20 cm (BDT-5); and combined tillage - light disc harrowing to 6-8 cm followed by incorporation of regrown biomass with heavy disc harrows to 18-20 cm (BDM-7 + BDT-5). It was found that the method of green manure incorporation had a significant effect on the agrophysical characteristics of soil fertility. The combined tillage (BDM-7 + BDT-5) ensured the formation of a loose (1.31 g cm³) soil structure in the 0-20 cm layer and a dense (1.51 g cm³) structure in the 20-50 cm soil layer. The highest soil moisture was recorded under combined incorporation (+4.91% compared to the initial level), while the lowest soil moisture was observed after shallow tillage due to increased evaporation. Strong correlation was found between field water capacity and soil density. The maximum soybean yield (2.93 t ha) was obtained in the variant with combined green manure incorporation which exceeded that of the variant with light disc harrows by 19.5% and the variant with heavy disc harrows by 20.6%.