毛竹林氮素营养诊断的研究

Study on Nutrient Diagnoses of Phyllostachys heterocycla var. pubescens Stand

结合“四因素二次回归最优设计”的施肥试验,在毛竹林小年施肥后至大年新竹长叶的不同生长季节,采样分析了叶片氮和叶绿素含量的变化规律;对不同生长季的叶片含氮量及叶绿素含量与新竹产量进行回归分析显示:12月采集的叶样,叶片含氮量与新竹产量呈显著的抛物线回归关系,4月出笋期采集的叶样,叶绿素含量也与新竹产量呈显著回归关系;利用氮含量方程求算留养密度2 180株/hm2的毛竹林最高理论产量相应的最适养分含量和临界值,分别为31.15mg/g和32.55mg/g;对叶片氮含量及叶绿素含量进行相关分析发现:施肥后一个月(9月)两者呈显著的直线相关关系,冬季(12月)两者呈显著或极显著的抛物线回归关系,说明毛竹叶营养与内部生理指标间具很强的内在联系。

By the optimum design of four factors quadratic regression, analysis was carried out on the dynamic regularity of nitrogen and chlorophyll content of Phyllostachys heterocycla var .pubescens foliage at different growing seasons. Regression analysis of nitrogen and chlorophyll content of these foliage and new bamboo leaves resulted a significant parabola regression correlation between nitrogen content of foliage collected in December and yield of new bamboo culm, and the same between chlorophyll content of foliage collected in April and yield of new bamboo culm. The optimum nutrient content and critical value of bamboo forest with 2 180culm/ha, the highest theory yield, calculated by regression equation were 31.15mg/g and 32.55mg/g. Correlation analysis on nitrogen and chlorophyll content of foliage showed that there was a linear correlation between them one month after applying fertilizer (in September), but a significant or remarkable significant parabola regression correlation in winter (December). This means there was a significant correlation between the nutrient content of leaves and physiological index in Ph. heterocycla var.pubescens.