准噶尔盆地南缘梭梭树干液流规律比较

Comparative Study on the Rule of Stem-sap Flow of Haloxylon ammodendron in the Southern Marginal Zone of Junggar Basin

采用SF-300热脉冲树干液流仪,分析比较了准噶尔盆地南缘人工种植和原生条件下,梭梭树干液流及其土壤水分的变化,建立了人工种植梭梭树干液流速率与气象因子的最优回归方程。结果表明:人工种植梭梭日累积液流量过程线呈近似"S"型,与土壤含水率具有极显著的相关性;液流速率日变化多呈双峰型,昼夜变化明显,对气温的时滞约1 h;原生梭梭耗水特征相对稳定,日累积液流量过程线近似直线型,与土壤含水率无相关性,液流速率日变化多呈多峰型,无明显日过程。观测期人工梭梭单位面积液流通量平均为0.240 L/(cm2.d),是原生梭梭的1.5倍;降雨后人工和原生梭梭液流速率峰值分别比降雨前提前3 h和30 min。

The trunk sap flow and soil moisture content of artificially-planted and natural Haloxylon ammodendron growing in the southern marginal zone of Junggar Basin,Xinjiang,China were measured with the SF-300 heat-pulse technique,and the data were analyzed and compared.An optimum regression equation between trunk sap flow velocity of artificially-planted Haloxylon ammodendron and meteorological factors was developed.The results show that the curve of daily cumulative trunk sap flow flux of artificially-planted Haloxylon ammodendron was S-shaped,and the correlation between daily cumulative trunk sap flow flux and soil moisture content was very remarkable;the curves of daily change of trunk sap flow velocity were mostly bimodal,the change of circadian rhythm was obvious,and the time lag to air temperature was for about one hour;water consumption of natural Haloxylon ammodendron was relatively stable,the curve of daily cumulative trunk sap flow flux of natural Haloxylon ammodendron was approximatively beeline-shaped,there was no correlation with soil moisture content,and the curves of daily change of trunk sap flow velocity were mostly in a multi-peak shape without obvious daily process.The average value of trunk sap flow flux of artificially-planted Haloxylon ammodendron was 0.240 L/（cm2·d） during the observation period,it was 1.5 times of that of natural Haloxylon ammodendron.After rainfall,the peak value of sap flow velocity of artificially-planted and natural Haloxylon ammodendron was moved up for 3 hours and 30 minutes respectively compared with that before rainfall.