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陕北黄土丘陵沟壑区属温带半干旱季风气候区,以旱地雨养农业为主。年降雨量为324—575mm,由于年变率大,季节分配不均,春旱、伏旱连年发生,加之蒸发量大,水分供需矛盾突出,导致农业产量低而不稳。该区川道地约占总耕地面积的10％左右,一般粮食产量占全区总产量的40％左右。充分往挥其生产潜力,对于促进该区农业持续稳定的增长具有举足轻重的作用。为此,我们依据该区多年的气候资料、主要农作物生育期及产量资料,估算了不同供水条件下的作物产量。为合理配置作物,确定作物的灌溉时期和灌溉量提供依据。(一)主要作物的最大气候生产力作物最大气候生产潜力的估算,采用联合国粮农
The loess hilly and gully regions in northern Shaanxi belong to the temperate semi-arid monsoon climate zone, with dryland rain-fed agriculture as its mainstay. Annual rainfall of 324-575mm, due to large annual variation, uneven seasonal distribution, spring drought, drought occur year after year, combined with evaporation, water supply and demand prominent contradiction, resulting in low and unstable agricultural output. The Chuan Road in this area accounts for about 10% of the total cultivated land, and the general grain output accounts for about 40% of the total output in the region. Fully exerting its potential for production has a pivotal role in promoting the sustained and steady growth of agriculture in this area. For this purpose, we have estimated crop yields under different water supply conditions based on years of climatic data, growth periods of main crops and yield information in the area. In order to rationally dispose of crops, determine the irrigation period of crops and provide the basis for irrigation. (I) Maximum climatic productivity of main crops The estimation of the maximum climatic production potential of crops, using the UN Food and Agriculture