Journal of Geographical Sciences ›› 2009, Vol. 19 ›› Issue (3): 331-339.doi: 10.1007/s11442-009-0331-6

• Climate and Environmental Change • Previous Articles     Next Articles

Topographic differentiation simulation of crop yield and soil and water loss on the Loess Plateau

XU Yong1, YANG Bo1, LIU Guobin2, LIU Puling2   

  1. 1. Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China|
    2. Institute of Soil and Water Conservation, CAS, Yangling 712100, Shaanxi, China
  • Received:2008-12-21 Revised:2009-03-03 Online:2009-06-25 Published:2009-06-25
  • Supported by:

    Knowledge Innovation Project of the Chinese Academy of Sciences, No.KZCX2-XB2-05-01; National Natural Science Foundation of China, No.40771086

Abstract:

De-farming slope farmland has been an effective measure in recent years for the improvement of the eco-environment and the mitigation of soil and water loss on the Loess Plateau. This paper, taking the Yangou Basin as a case study and using day-by-day meteorological data of Yan’an station in 2005, simulated and analyzed the quantitative relation between crop yield, soil and water loss and topographic condition with the aid of WIN-YIELD software. Results show that: 1) topographic gradient has important influence on crop yield. The bigger gradient is, the lower the crop yield. Yields of sorghum and corn decrease by 15.44% and 14.32% respectively at 25° in comparison to the case of 0°. In addition, yields of soya, bean and potato decrease slightly by 5.26%, 4.67% and 3.84%, respectively. The influences of topographic height and slope aspect on crop yield are slight. 2) Under the same topographic condition, different crops’ runoff and soil loss show obvious disparity. Topographic gradient has important influence on soil and water loss. In general, the changing trend is that the soil and water loss aggregates with the increase of gradient, and the maximal amount occurs around 20°. The influence of topographic height is slight. Topographic aspect has a certain effect, and the fundamental characteristic is that values are higher at the aspect of south than north. 3) Topographic gradients of 5° and 15° are two important thresholds. The characteristic about soil and water loss with the variation of topographic gradients show that: the slope farmland with gradient less than 5° could remain unchanged, and the slope farmland more than 15° should be de-farmed as early as possible.

Key words: crop yield, soil and water loss, topographic differentiation, Loess Plateau