The study looked at how farmers in southwest China manage nutrients in their paddy rice-upland crop rotation. They found that farmers often use too much nitrogen fertilizer and not enough phosphorus and potassium. The timing of nitrogen application doesn't match the crops' needs. Farmers also don't consider the environment's nutrient contributions or how nutrients change throughout the rotation. The researchers suggest a new strategy that considers the whole rotation system, uses different nutrient sources, and integrates nutrient management with other farming techniques.