The researchers studied how different farming practices affect the levels of important nutrients in the soil during a rice-wheat cropping system. They found that tilling the soil and keeping it submerged in water helped increase the availability of iron, manganese, and copper to rice plants, but decreased zinc levels. After one cycle of rice-wheat, the soil's nutrient levels decreased, but adding farmyard manure and Leucaena plants slowed down this decline. Additionally, applying sewage sludge increased all the studied micronutrients in the soil.