两个苹果品种不同枝类叶营养含量年周期变化及营养诊断方法研究

通过对瓦里短枝和长富2号两个品种不同枝条类型叶片取样，测定分析了苹果树不同生育阶段叶片营养元素含量变化特征，为营养诊断采集标准叶样和指导施肥提供依据。结果表明，不同采样时期、 不同枝类叶片营养元素含量差异很大，以新梢停止生长期的各类枝条叶片营养元素含量最为接近。在年周期中，叶片营养元素含量变异系数从小到大顺序为营养枝＜中枝＜长枝＜短枝＜叶丛枝。常量营养元素含量周年变化幅度小于微量元素，氮含量变幅最小，锰变幅最大。品种间除硼元素含量变化有差异外，其它营养元素含量变化趋势相近或相同。随树体生育进程，叶片营养元素含量变化规律为氮、 磷、 铜含量呈降低趋势；钾、 锌、 铁、 硼含量呈波动状态；钙、 镁含量至新梢停止生长期最高，且枝条长度越小，含量越高；锰含量变化近似正态分布。苹果新梢停止生长期是叶片养分最稳定时期，营养枝是叶最佳采样枝类。

Study on the annual variations of foliar nutrient contents from different branches and nutrition diagnosis methods of two apple cultivars

 Leaf samples were collected in the branches at different positions in different growth periods in two apple cultivars (Wallee spur Del and Nagafu 2), and the nutrient contents were analyzed to investigate the characteristic of nutrition annual variation  and to provid a base for choosing proper leaf samples at right position and sensitive growth period for the fertilization recommendation. The results showed that the nutrient contents in the leaves from different sampling period and different branches varied heavily. In the year cycle，the nutrient contents in the leaves from different branches are similar when the new shoots stop growing. The seasonal variation of the macronutrient contents is less than that of microelements. The least variation in nutrient content is in N and the largest in Mn. The annual variable coefficient of the nutrient contents in leaves is in order of vegetative shoot＜middle length branch＜long shoot＜short branch and a cluster of leaf branch. Excepting boron, the annual change curves of nutrients in the two cultivars are similar. With development progress, the dynamics of nitrogen, phosphorus and copper contents exhibits decreasing trend, and that of potassium, zinc, iron and boron fluctuates. The highest calcium and magnesium contents appear at the growth stopping period of new shoots in the shorter branches. The  nutrient contents in leaves are the most stable at the growth stopping period at young shoots, therefore, they can be used as the samples for nutrient diagnosis. The leaves of vegetative branches are the best sampling branches.