关键词: 苏南地区, 稻田, 肥力演变, 养分平衡, 合理施肥量

Abstract: Taking Yuzhong County from Gansu Province as an example, using the InVEST model, ArcGIS, R and GeoDa software, and based on spatial hotspot analysis, correlation analysis and spatial autocorrelation analysis, we examined the spatial heterogeneity and potential tradeoffs and synergies of five typical ecosystem services in 2015 at the village scale, including biodiversity maintenance, soil retention, water yield, carbon storage and food supply. The five ecosystem services showed obvious spatial heterogeneity. The biodiversity maintenance, water yield and carbon storage showed a threeorder gradient decrease from south to central to north. The capacity of soil retention was high in the south, moderate in the north, and low in the middle area. The food supply was high in the middle area and low in the south and north. The hotspot analysis showed that the spatial concordance among multiple ecosystem services was relatively high. The high-value clusters (hot spots) of ecosystem services were mainly located in the southern mountainous regions, the lowvalue clusters (clod spots) were mostly distributed in the northern loess hilly regions, while the highvalue clusters of food supply services were mainly located in the central areas, and the lowvalue clusters were concentrated in the northern loess hilly regions. The results of correlation analysis and bivariate Moran’s I analysis showed that there were tradeoffs between food supply and the other four types of ecosystem services. Specifically, the food supply had strong tradeoffs with soil retention and biodiversity maintenance, and weak tradeoffs with carbon storage and water yield. Relationships among the biodiversity maintenance, soil retention, water yield, and carbon storage were mainly characterized by synergies with different degrees. Spatially,there was strong heterogeneity of tradeoffs and synergies among different ecosystem services.

Key words: Southern area of Jiangsu Province, Paddy field, Fertility evolution, Nutrient balance, Reasonable fertilizer application amount