Organic manures like cow and chicken manure can replace chemical fertilizers to improve crop yield and nutrient use efficiency in rice-wheat systems. By using manures instead of chemicals, farmers can increase production and nutrient uptake while also benefiting the soil and environment. Substituting even a portion of chemical fertilizers with organic manures can lead to better yields and nutrient content in crops like wheat. Manure application can also enhance water use efficiency in winter wheat but may decrease it in summer maize. Overall, using organic manures can be a sustainable and effective way to improve agricultural productivity while reducing reliance on harmful chemical fertilizers.