运用投影寻踪法建立苹果树蒸腾量的预测模型

Establishment of Prediction Model for Apple Tree Transpiration with Projection Pursuit Method

[目的]运用投影寻踪回归分析法建立苹果树蒸腾量的预测模型,为更方便更好地预测苹果树蒸腾量提供指导。[方法]根据2009年5～9月气象站观测数据,对气温、相对湿度、风速、太阳辐射、大气压、土壤温度、叶温和水面蒸发量进行分析,并应用投影寻踪回归分析法建立了各气象因子与苹果树蒸腾量的预测模型。[结果]气象数据分析表明,大气水势随着气温增高呈减小的趋势,但随着气温降低和湿度增加而增加。气温、净辐射与作物叶水势均呈抛物线关系。随着净辐射的增大,作物消耗的水量增大,叶水势降低。由叶水势与土壤含水率关系可知,当土壤含水率减少时,苹果根系难以吸收到足够的水分,不能满足叶片蒸腾耗水的需求,导致叶片含水量偏低,叶水势也随着下降。苹果叶水势随着土壤含水率的降低而降低。[结论]运用投影寻踪回归分析法建立了气象因子对苹果树蒸腾量的预测模型,且预测精度较高。

[Objective] The aim was to establish prediction model for apple tree transpiration by using projection pursuit method,and provide guidance for better predicting the transpiration.[Method] According to weather station observation data during May-Sep.2009,the temperature,relative humidity,wind speed,solar radiation,atmospheric pressure and soil temperature,leaf temperature,water evaporation were analyzed,the prediction model between each weather factor and apple tree transpiration was established by using projection pursuit regression analysis method.[Result] The meteorological data analysis showed that the air water potential decreased with the temperature increased,and increased with temperature decrease and humidity increase.The temperature,net radiation and crop leaves were in the water parabola relation.Along with the increase of the net radiation,the crop water consumption increased,and the leaf water potential decreased.From the relationship between leaf water potential and soil moisture content,it was known that when the soil moisture content is declined,apple root couldn＇t absorb enough moisture,and meet the demand of consumption,which lead to leaf in low water content,water potential leaf blade declined.Apple leaf water potential decreased with the soil moisture content decrease.[Conclusion] The prediction model of meteorological factor to apple tree transpiration was established by using projection pursuit method,and the prediction precision was high.