[Systematic analysis on water ecological adaptability of upland crops in loess hilly zone]

Based on the survey and experimental results, this paper analyzed the time-sequence relationship between crop growth and rainfall distribution, and the potential water use rate, water supply-demand equilibrium and deficit features of different upland crops in the loess hilly zone of south Ningxia. The model of water ecological adaptability index (WEAI) was proposed to evaluate these features of upland crops. The results showed that autumn crops were superior to summer crops in the coupling characteristics between crop growth and rainfall distribution. There were also differences in rainfall potential use rate among crops, the order being: perennial crops > root and stem crops > grain crops; autumn crops > summer crops. The water satiety rate and water ecological adaptability were higher for autumn crops than for summer crops, and higher in rainy years than in dry years. In line with water ecological adaptability index, the 6 main crops could be put in order of millet > potato > panic > flax > pea > spring wheat. The results of this study may provide theoretic basis for drawing up the decision scheme of cropping system in upland regions.