林地环境因子对油茶春梢生长期液流动态的影响

摘要

In order to research dynamic of sap flow velocity (SFV) in Camellia oleifera tree at spring shoot growing stage,SFV and environmental factors in the field were measured by sap flow measurement technique with thermal diffusion probe and micro-meteorological station from March to May.The results indicate that,daily mean temperature sharply increases to 27.5 ℃ from 7.5 ℃,and water in soil is sufficient in spring shoot growing stage.SFV fluctuates frequently with environmental factors changing,and weather order based on SFV from high to low is sunny day,cloudy day,overcast sky,rain day.The results of correlation analysis and stepwise regression analysis indicate that solar radiation,photosynthetic active radiation and temperature have significant correlation with SFV,but air humidity has a significant correlation with it.With weather change from sunny day,cloudy day,to overcast sky,the correlation coefficient of SFV is decreased with radiation,but it is increased with temperature,and it is no obvious change with wind velocity and soil moisture.The regression models between SFV in different weather conditions and environmental factors were established.The model is up to significant level,and determination coefficients are over 0.93 except rain day.%为了研究油茶春梢生长期液流的动态变化规律,利用植物径流仪及自动气象记录仪,对盛果期油茶春梢生长期(3月～5月)的液流动态及林地环境因子进行了连续监测,研究结果表明:在春梢生长期林地土壤的水分充足,日平均气温由7.5℃大幅上升至27.5℃；春梢生长期油茶液流随环境因子变化的波动较大,不同天气的液流大小为晴天＞多云＞阴天＞雨天.液流与环境因子的相关分析及逐步回归分析结果表明,总辐射、光合有效辐射、气温对液流的相关系数极高,空气相对湿度与液流有较高的负相关；随着天气由晴天到多云再到阴天的变化,液流与辐射的相关系数降低而与气温的相关系数增高,风速和土壤湿度与液流的相关性无明显变化规律;对不同天气的液流与环境因子建立了回归模型,回归模型都呈极显著水平,晴天、多云、阴天的决定系数都在0.93以上.