黄土高原苹果园深层土壤干燥化特征

Characteristics of deep soil desiccation of apple orchards in different weather and landform zones of Loess Plateau in China

为了评价黄土高原苹果产区深层土壤干燥化特征及其区域分布规律,测定了其半湿润黄土台塬区(Ⅰ)、半湿润易旱黄土旱塬区(Ⅱ)、半湿润偏旱和半干旱黄土丘陵区(Ⅲ)等不同气候和地貌类型区32块苹果园地0～1500cm土层土壤湿度,定量比较和分析了各类型区苹果园地深层土壤含水率、土壤湿度剖面分布及其土壤干燥化特征。结果表明:1)Ⅰ、Ⅱ、Ⅲ区苹果园地0～1500cm土层土壤含水率依次为17.53%、13.44%和10.29%,土壤有效贮水量依次为1273.70、973.98和864.05mm,土壤水分过耗量依次为199.93、465.10和362.70mm,年均土壤干燥化速率依次为8.47、26.29和23.44mm/a。人工补灌、树龄、种植密度和地貌类型等因素影响果园土壤湿度和土壤干燥化程度。2)各区有补充灌溉的果园土壤剖面湿度显著高于旱作果园,不存在或部分土层存在干燥化现象;旱作果园土壤剖面均存在深厚的干燥化土层。3)Ⅰ、Ⅱ和Ⅲ区有补充灌溉的苹果园地土壤干燥化指数(SDI)分别为-8%、-11%和-34%;旱作果园土壤干燥化指数(SDI)分别为32%、50%和46%,各类型干层厚度分别达到或超过790、1297和910cm。研究结果为黄土高原苹果园地深层土壤水分可持续利用和苹果生产基地可持续发展提供参考。

In order to assess the deep soil desiccation and its regional distributing characteristics in apple production areas of the loess plateau, the research was carried out via widely observations of soil moisture in 0-1 500 cm soil layers of apple orchards in different weather and landform zones on the Loess Plateau. The soil water amount, soil moisture distribution in deep soil profile and soil desiccation of 32 apple orchards in semi-humid loess terrace-land zone （ Ⅰ ）, semi-humid and prone drought loess highland zone （ Ⅱ ）, and semi-humid prone drought and semi-arid loess hilly zone （Ⅲ） were analyzed and compared, and soil desiccation characteristics of apple orchards were assessed quantitatively. The results showed that, 1） Average soil moisture in 0-1 500 cm soil layers of apple orchards in zone Ⅰ, Ⅱ and Ⅲ was 17.53%, 13.44% and 10.29%, respectively, average available soil water storage was 1 273.70, 973.98 and 864.05 mm, respectively, average soil water overuse was 199.93, 465.10 and 362.70 mm,, respectively, and average soil desiccation rate was 8.47, 26.29 and 23.44 mm/a in three zones, accordingly. Soil moistures and desiccated soil layer distributions in apple orchards were affected by weather, landform, irrigation, apple tree age and planting density; 2） Soil moisture of apple orchards with supplementary or regular irrigation was significantly higher than that of dryland orchards in the same zone at whole observed depth of soil layers, and no soil desiccation or limited soil desiccation occurred, while relatively deep desiccated soil layers existed in dryland orchards; 3） SDI （soil desiccation index） of apple orchards with supplementary or regular irrigation in Zone I , II and III was -8%, -11% and -34%, respectively, while SDI of dryland apple orchards was 32%, 50% and 46%, with desiccated soil layer thickness of 790, 1297 and over 910cm in three zones correspondingly. The results can provide a scientific basis and basic data for deep soil water sustainable utilization of apple orchards and sustainable development of apple production bases on the Loess Plateau.