Soil and water conservation and dryland farming performance: An emergy synthesis perspective on three typical farming systems in the Loess Plateau of China

The Loess Plateau has historically suffered from severe soil erosion and land degradation. After the implementation of soil and water conservation (SWC) programs by the Chinese government since 1999, the land productivity and environmental conditions in this region have greatly improved. However, how SWC could contribute to dryland farming performance there remains unclear. Combining RUSLE, the Water Yield module of InVEST, and ArcGIS, emergy synthesis was creatively used to reveal the mechanisms of SWC contribution to three typical systems of dryland farming in the Loess Plateau: crop farming, apple farming and stock farming. Findings indicated that: (1) a 49.2% reduction in soil erosion intensity and a 78.7% increase in water retention capacity substantially enhanced dryland productivity, but increased external inputs such as fertiliser, electricity and machinery have a slight negative effect on the sustainability of crop farming from 2000 to 2020. (2) The spatiotemporal patterns of crop and stock farming were adjusted to fit changing ecological, economic and social conditions. (3) Although an annual average expansion of 270 km 2 in apple farming provided farmers considerable profits at the early stage of SWC programs, concerns have increased about spreading into marginal lands and rising inorganic energy inputs over the past two decades. We conclude that the combination of SWC-based agriculture and organic agriculture is the main direction of sustainable dryland farming in the Loess Plateau. We recommend that the main measures of sustainable dryland farming in the region include reduced external inputs in crop farming, moderate size and water retention mulching of apple farming, and conversion of confined breeding into grassland-based stock farming. We argue that emergy synthesis used in this work greatly enhances the mechanistic understanding of SWC contribution to dryland farming of the Loess Plateau.