覆土砒砂岩区沙棘耗水量及其影响因子

Water Consumption of Hippophae rhamnoides and Its Affecting Factors in Loess-Covered Pisha Rock Area

为明确沙棘的耗水特征及其主要影响因子,从而为水土保持林的可持续管理提供理论依据,利用TDP技术监测生长季5年生沙棘的液流动态,计算沙棘耗水量,通过相关分析和回归分析等方法研究了它们与气象因子的关系。结果表明:晴天沙棘的液流通量为单峰曲线,干旱时则为双峰曲线。雨天沙棘的液流通量为单峰、双峰或多峰曲线。晴天沙棘液流通量的最大值是7.13~23.07 g/(cm^2·h)。7月降雨后液流通量最高,6月干旱时最低。生长季沙棘液流通量和单株日耗水量与气温、光合有效辐射(PAR)和水汽压亏缺(VPD)均呈显著正相关,而与相对湿度呈显著负相关。而且,液流通量与风速呈显著正相关,单株日耗水量与降水量呈显著负相关。晴天沙棘单株耗水量最大值是146.39~363.30 g/h。生长季沙棘的单株总耗水量是185.77~219.44 kg,平均值为206.58 kg。因此,建议保持沙棘林的合理密度,维持其水分平衡,从而确保沙棘林的长期稳定性。

In order to clarify water consumption of Hippophae rhamnoides and the affecting factors,and give theoretical support to the sustainable management of water and soil conservation plantation,sap flow dynamic of five-year old Hippophae rhamnoides was monitored by TDP technology and its water consumption was calculated.Their relationships with climatic factors were analyzed by correlation and regression.The results showed that sap flow of Hippophae rhamnoides was single peak curve in sunny days,was double peak curve during drought,was single,double or multiple peak curve in rainy days;the daily maximal value of sap flow of Hippophae rhamnoides was 7.13~23.07 g/(cm^2·h)in sunny days;sap flow was maximal in July after rain and minimal in June during drought;sap flow and daily water consumption were positively correlated with air temperature,photosynthetically active radiation and vapor pressure deficit,but was negatively correlated with relative humidity in the growing season;moreover,sap flow was positively correlated with wind speed;daily water consumption was negatively correlated with precipitation;the daily maximal value of sap flow of Hippophae rhamnoides was 146.39~363.30 g/h in sunny days;the total water consumption of Hippophae rhamnoides was 185.77~219.44 kg per plant in the growing season,with the mean of 206.58 kg.Therefore,it is suggested that the proper density should be maintained for Hippophae rhamnoides plantation to sustain its water balance and keep its stability.