The study looked at how different green manure crops affect soil health and nutrient levels. They found that adding biomass from certain crops like Sesbania rostrata and Crotalaria juncea increased nitrogen levels in the soil. Sesbania rostrata and Sesbania aculeata improved soil quality the most, followed by Crotalaria juncea and Vigna unguiculata. These crops helped maintain a positive balance of nutrients in the soil compared to others.