水保所知识产出(1956---)知识库

为了探明黄土高原半干旱区山地枣林蒸腾和土壤水分间的关系，对山地枣林的土壤水分和枣树茎液流动态
进行了连续3 年的定位监测，结果表明: 土壤含水率时空变异性显著，垂直方向上随着土层深度的增加，变异系数
( Cv
) 逐渐降低。其自上而下可划分为土壤水分变化层( 0 ～ 2. 6 m) 、土壤水分干层( 2. 6 ～ 6. 0 m) 和土壤水分恢复层
( 6. 0 ～ 10. 0 m) 。枣树液流监测的参数在生育期和休眠期间具有显著性差异，根据这一特征可以对枣树生育期进
行较为准确的界定。基于液流参数特征确定的生育期与观察树体萌芽、落叶确定的生育期时长基本一致，均约为
160 d，但基于液流参数确定的生育期较后者约提前5 d。土壤水分的增加会使枣树液流( 瞬时蒸腾) 的谷值出现时
间提前，峰值出现时间推后，“午休”时间缩短，旺盛蒸腾时间延长，反之亦然。枣树生育前期蒸腾均呈逐日增加趋
势，而生育中后期蒸腾和土壤水分呈极显著的正相关关系。

In order to explore the relationships between jujube tree transpiration and soil moisture in
semi-arid loess hilly area，soil moisture and jujube tree sap flow were monitored for three consecutive
years． Ｒesults showed that temporal and spatial variability of soil moisture were significant． Soil moisture
increased with the increase of soil depth but its coefficient of variation decreased gradually in the vertical
direction． According to the variation of soil moisture，soil depth was divided into three layers from top to
bottom: soil moisture changing layer ( 0 ～ 2. 6 m) ，dried soil layer ( 2. 6 ～ 6. 0 m) and soil moisture
recovery layer ( 6. 0 ～ 10. 0 m) ． Parameters of jujube tree sap flow were significantly different between
growth period and dormant period，therefore，the growth period of jujube tree could be demarcated moreaccurately． The growth period divided based on sap flow characteristics lasted about 160 d，which was
similar to that determined by sprout and defoliation observation method，but it started and ended nearly
5 d in advance． The increase of soil moisture led to forward of minimum values and delay of maximum
values of jujube tree sap flow，the“lunch break”time was shortened，but the transpiration time was
strongly prolonged，and vice versa． Jujube tree sap flow increased at the early growth stage，and the
positive correlation between transpiration and soil moisture were significant at the middle and late growth
stages．