The purpose of the present study was to determine the agro-ecological advantages of growing leguminous crops compared to conventional cereals, particularly their impact on soil quality, biological activity, and productivity of agro-ecosystems. The study investigated the impact of leguminous crops – peas (Pisum sativum), lentils (Lens culinaris), and beans (Phaseolus vulgaris) – on soil physicochemical properties, microbiological composition, biological nitrogen fixation, yield and stability of agroecosystems in the arid conditions of southern Ukraine. The study was conducted in comparison with control plots sown with wheat (Triticum aestivum) and barley (Hordeum vulgare), which allowed assessing the effectiveness of leguminous crops in improving soil fertility and their contribution to maintaining agroecosystem sustainability. The results showed that the cultivation of leguminous crops contributed to an increase in humus content, increased soil capillary porosity, and improved water retention properties, while these indicators stayed lower in the control plots with cereals. The study also recorded a significant increase in the number of nitrogen-fixing (Bradyrhizobium, Azotobacter) and phosphorus-mobilising (Pseudomonas, Bacillus) bacteria in the plots with leguminous crops, which indicated an increase in biological processes in the soil. Yields of wheat and barley were dependent on the level of mineral nutrition, while leguminous crops provided a stable level of productivity without additional nitrogen fertilisation. The findings confirmed the feasibility of integrating leguminous crops into crop rotations to maintain soil fertility, improve microbiological balance, and reduce dependence on mineral fertilisers. It was found that biological nitrogen fixation by peas, lentils, and beans increases the level of available nitrogen in the soil, which positively influences the productivity of agroecosystems compared to conventional cereals
Drobitko et al. (Fri,) studied this question.