Nutrient cycling and balance characteristics of different farmland types in the loess hilly region

Based on data of the long-term fertilizer experiment of plain field, sloping field and terrace on Ansai station in loess hilly region, the nutrient cycling and balance characteristics of different farmland types were quantitatively analyzed. The result showed that N surplus amount of plain field was 10.22 kg/(hm²·a), while P₂O₅ was 56.57 kg/(hm²·a). N deficit amount of sloping field was 10.2 kg/(hm²·a), while P₂O₅ was 56.6 kg/(hm²·a). N surplus amount of terrace was 104.9 kg/(hm²·a), while P₂O₅ was 107.3 kg/(hm²·a). The vegetation rehabilitation and sloping field exchange terrace project were the key measures for improving the farmaland nutrient cycling system in the loess hilly region.