European Journal of Sustainable Agroecosystems

Introduction: Berseem (Trifolium alexandrinum L.), also known as Egyptian clover, is considered the major winter (rabi) forage legume crop in the region of Indian subcontinent, Nile Valley, and Mediterranean Basin owing to its high biomass production, capability of producing several rounds of fodder, and ability to fix biological nitrogen in the soil. Conservation agriculture (CA) is a special kind of agriculture that rests on the principles of minimum soil disturbance, maintaining adequate soil cover, and crop rotation/diversification. This system is often used in order to increase organic carbon (SOC) in the soil and restore productivity adversely affected by the intensive tillage techniques. When berseem legume plant with high biomass performance is used together with CA approaches, it can create opportunities to increase soil organic carbon and productivity at the same time, but the studies on berseem in literature are not as developed as those on the methods of CA that are usually applied to cereals.
Target: This written review seeks to critically evaluate previous research conclusions regarding the influence of conservation agriculture methods, including minimum and zero tillage practices, residue management, and methods of growing berseem (like relay cropping and crop rotation), on soil organic carbon levels and berseem crop yields. 
Literature sources: The data sources consist of information collected from different sources such as Scopus, Web of Science, ScienceDirect, SpringerLink (Agricultural Research), Frontiers, PMC, and the Indian Journal of Soil Conservation. This was done using the keywords "berseem", "Trifolium alexandrinum", "conservation agriculture", "zero tillage", "soil organic carbon", and "residue retention" along with the other information from ICAR and FAO reports on conservation agriculture.
Key takeaways: The application of the relay cropping technique and zero tillage approach to growing berseem in cereal and oilseed farming has brought about an increase in organic carbon in the soil beyond what taking the classic monoculture approach would achieve, as evidenced by the respective boosts in soil macro and micronutrient content and land-use efficiency of the area. If we consider the example of the five-year pearl millet-mustard farming model, berseem cultivation under zero tillage has resulted in developing a degree of surface residue that acts to absorb carbon and thus enhances the quality of soil. Yield being produced with the help of this approach gives an increase of 10-15% of pearl millet, paddy and green gram seeds as well as a 9-14% higher yield in mustard and mustard-equivalent yield as high as 33-66%. The practices of conservation agriculture and cereal zero tillage show that retention of residue and proper application of the principles of reduced tillage lead to SOC growth of the area due to enhancing aggregate stability and both active and passive carbon reserves, which can be used for maize and berseem systems.
Research gaps: There is a scarce presence of experiments specific to berseem and multiple locations over long periods of time investigating rates of SOC sequestration, contribution of roots versus shoots to carbon formation, and interaction between CA and berseem cutting management.
Conclusion: Conservation agriculture alone or together with use of berseem in relay or rotating legumes techniques serves as an effective and profitable option in terms of high yields achieved and soil carbon presence in cropland. Nevertheless, more research specifically related to berseem must be conducted in order to improve suggestions.