江西退化红壤区马尾松液流特征及其对气象因子的响应

Characteristics of Sap Flow of Pinus massomiana and Responses to Multiple Meteorological Factors in Degraded Red Soil Area

运用Granier热扩散法对马尾松树干液流速率及气象因子进行长期连续测定,探讨马尾松水分生理生态特征及其对气象因子变化的响应,为马尾松林水资源的有效利用和科学管理提供依据.结论如下：（1）不同胸径大小马尾松树干液流昼夜节律呈基本一致的单峰型变化,但液流启动和开始下降的时间存在差异；（2）不同月份晴天马尾松树干液流昼夜节律存在差异,4、9、10月呈单峰型变化,5-8月则呈宽峰型变化.5-9月液流启动时间比4、10月提早1～2h,迅速上升达到峰值后保持较大液流速率至少5h以上.平均液流速率关系依次为：7月（0.002 182） ＞6月（0.001 937） ＞8月（0.001 895） ＞9月（0.001 561） ＞5月（0.001 367） ＞4月（0.001 206）＞ 10月（0.001 123）.雨天马尾松树干液流明显低于同时期晴天液流水平,但树干液流昼夜节律由于降雨时段和降雨强度不同存在差异；（3）偏相关分析结果表明,液流速率与相对湿度呈显著负相关,与空气温度、平均净辐射和风速呈显著正相关,相关程度顺序为：平均净辐射（0.823＊＊）＞相对湿度（-0.744＊＊）＞空气温度（0.683＊＊）＞风速（0.411＊＊）.建立液流速率与上述气象因子的多元线性回归方程,回归方程和回归系数的相关性检验均达到极显著水平.

The sap flow velocity （Js, cm/s） of Pinus massomiana was measured using Granier＇ s thermal dissipation probe with simultaneous meteorological monitoring by the automatic weather station in Qianyanzhou ecological station. The aim of this paper was to analyze the sap flow dynamics of Pinus massomiana and its re- lationship with meteorological factors,utimately providing basis accordance for efficient utilization and scientific management of water resource in Pinus massomiana plantation. The results revealed that ： （ 1 ） there was no signifi- cant difference in diurnal fluctuations of tree sap flow in two diametvic classes, but this was not the case for initi- ating time in the early morning and declining time in the late afternoon; （2）the diurnal variation of sap flow on sunny days varied among different observing months ; the diurnal fluctuations of sap flow displayed single - peak- ed curves in April,September and October while broad -peaked curves from May to August. Sap flow initiated I -2 h earlier from May to September than that in April and October and maintained a relatively high level o- ver 5 hours after the peak ; the average sap flow velocity followed the order of July （ 0. 002 182 ） 〉 June （0.001 937） 〉August（0.001 895） 〉 September （0.00/ 561） 〉May（0.001 367） 〉April （0.001 206） 〉 October（ 0. 001 123 ） ;on rainy days, sap flow velocity was much lower than that on sunny days within almost the same period;the diurnal changes of sap flow showed remarkable difference due to the duration of time and intensity of precipitation ; （3） partial correlation analysis showed that there existed significantly positive correla- tions between sap flow velocity and air temperature （Ta）, average net radiation （ANR） and wind velocity （ Ws）, and significantly negative correlation between sap flow velocity and relative humidity （Rh） ; the correla- tion strength was as follows ： ANR （0. 823 ＊＊ ） 〉 Rh （ - 0. 744 ＊＊ ） 〉 Ta （0.683 ＊＊ ） 〉 Ws （0.411 ＊＊ ）. A multiva- riant linear model was established to describe the integrated effects of four meteorological factors on sap flow velocity. The regression model and all parameters were significant at 1% safety.