Relay sowing of berseem (Trifolium alexandrinum) in mustard (Brassica juncea) improves system productivity, economics and soil fertility

Mustard-based mono-cropping systems have been experiencing a decline in productivity, economic profitability and soil quality in India's arid and semi-arid climate. An on-farm research study was conducted from 2017-18 to 2021-22 to address these issues. This study focused on the relay cropping of the legume fodder crop berseem (Trifolium alexandrinum L.) alongside standing mustard, which was grown after fallow, pearl millet, paddy and green gram-based cropping systems. Including berseem as a relay crop in mustard cultivation, significantly greater soil organic carbon and its stock, macro- and micronutrient availability in soil and use-efficiency of land. Enhancements physicochemical properties of soil led to an increase in seed yields of pearl millet, paddy and green gram by 10-15%, followed by a 9-14% increase in mustard yield as compared to the existing cropping systems. Notably, the highest seed yield of berseem occurred when it was relay seeded in a fallow-mustard cropping system, followed by green gram-mustard and pearl millet-mustard. The lowest yield was observed in paddy-mustard cropping systems. The studies revealed that the mustard equivalent yield (MEY) in the legume-based relayed berseem cropping systems increased by 33- 66%, resulting in an additional net profit ranging from ` 40,000-51,000 ha-1 as compared to traditional cropping systems. Water productivity was significantly enhanced by 5- 14% when relay cropping berseem in mustard-based systems. However, it declined by 15% when berseem was relayed after mustard was grown in the fallow kharif season. Overall, the trend for MEY and net returns under the relay cropping of berseem in mustard-based systems was ranked as follows: paddy-mustard > pearl millet-mustard > green gram-mustard > fallow-mustard. This study demonstrated that relay cropping of berseem within mustard-based cropping systems can improve crop productivity, increase net profitability, enhance water productivity and positively affect soil physicochemical properties.