陕西渭北旱塬苹果种植分区土壤水分特征研究

以渭北旱塬为研究对象，在区域尺度和定位观测的基础上，揭示了渭北不同苹果种植分区土壤水分特征。得出如下结论：(1)渭北旱塬不同苹果种植分区土壤水分特征主要受自然降水和苹果地蒸散量的影响。(2)3种类型区苹果地土壤水分都存在亏缺现象，台塬东部区苹果地土壤水分平均潜在亏缺量为390．9mm，最大亏缺量为674．6mm，最小亏缺量为186．3mm；高原沟壑区苹果地水分平均潜在亏缺量、最大亏缺量分别为264．4和441．2mm，有时也出现水分盈余的现象；台塬西部区总体上表现为亏缺．但苹果地出现水分盈余的现象较高原沟壑区普遍，最大盈余量达151．8mm；(3)渭北旱塬苹果地水分储存量也存在区域分异，2m土层水分储存量在全生育期是渭北台塬西部区大于渭北高原沟壑区大于渭北台塬东部区，土壤水分储存量的变化特性与降水量的时空变化、苹果树对土壤水分的利用量及降水年型有关；(4)3种类型区苹果地耗水量以台塬东部区最大，旱塬沟壑区次之，台塬西部区最小。干旱年苹果全生育期耗水量低于丰水年份。从耗水组分上看，苹果地耗水主要来源于生育期间的有效降水，但在干旱年份，耗水量还有相当一部分依赖深层土壤贮水，耗水深度超过3m，表明深层储水在干旱年份对苹果树生长所需水分的供给起着不可忽视的重要作用。

Study on the Characteristics of Soil Moisture Content in the Apple Growing Subregions of the Weibei Dry Highland In Shaanxi Province

In this paper, the characteristics of soil moisture content in the different apple growing subregions of the Weibei Dry Highland in Shaanxi Province are revealed based on the stationed observation. The conclusions are as follows: (1) The characteristics of soil moisture content in the different apple growing subregions of the Weibei Dry Highland are mainly affected by precipitation and the evapotranspiration of the apple fields. On the regional scale, and the potential evapotranspiration of the apple fields is the highest in the eastern part of the highland, then in the ravine area, and it is the least in the western part. (2) The soil moisture is deficient in the 3 apple subregions: the average, maximum and minimum deficiencies of soil moisture are 390.9 mm, 674.6 mm and 186.3 mm respectively in the eastern part; the average and maximum deficiencies of soil moisture are 264.4 mm and 441.2 mm respectively in the ravine area, and the surplus of soil moisture occurs sometimes; the soil moisture is generally deficient in the western part, but the surplus of soil moisture is more universal than that in the ravine area, and the maximum surplus of soil moisture is 151.8 mm. (3) The soil-conserved moisture is different from the different regions in the highland, which is mainly related to precipitation. (4) Water consumption of apple fields is the highest in the eastern part, then in the ravine area, and it is the least in the western part. Water consumption of apple fields comes mainly from the effective precipitation during the growing stage of apple trees, but a certain part comes from the deep soil-conserved moisture in dry years, and the depth of water consumption of apple trees is deeper than 3 m, which reveals that the deep soil-conserved moisture plays an important role in the growth of apple trees in dry years.