Farming system generally consists of several components including soil system,crop system and regional climatic system which are relatively independent but closely associated with each other.It is involved crop cultivation pattern,crop type,weeds,pests and soil & water resource management in farmland and so on,which plays an important role in ecosystem management and sustainable agricultural development in the Loess Plateau.Over past fifty years(1951-2000),the annual average temperature increased by 1.1 ℃,a...