不同方法在巨桉人工林养分诊断中的应用

Applications of different nutrient diagnosis methods in Eucalyptus grandis plantation in Sichuan

【目的】对比分析了3种养分诊断方法对四川巨桉人工林叶片养分的诊断结果,为林木养分诊断筛选诊断方法和提供诊断标准。【方法】在四川巨桉人工林分布区设立60个标准地,分别采用临界值法(CVA)、DRIS法和相对生长速率法(RGR),对巨桉人工林叶片养分进行诊断。【结果】采用临界值法(CVA)进行诊断,K、Ca、S、Cu、Zn、Fe、Mn等养分元素诊断结果无效,P诊断结果易出现负值,N、B诊断结果受采用的生长量指标影响较大,仅Mg诊断结果较为稳定;DRIS法对Zn、Fe、Mn 3种养分元素的诊断明显属于误诊,其他养分元素诊断结果相对较为可靠;相对生长速率法(RGR)对11种养分元素均可得出有效的诊断结果,具有较高的参考价值,并据此制定了四川省巨桉人工林叶片养分诊断标准。【结论】临界值法受年龄、降雨、温湿度、养分交互效应影响,诊断结果有效性较低;DRIS法选取样本数量较大,对高水平和低水平养分平衡关系无法进行有效诊断;相对生长速率法需要样本数量较少,充分考虑林分生长潜力,诊断结果更符合实际。

[Objective] The study was conducted to contrast three nutrient diagnosis methods and to give appropriate nutrient diagnosis method and standard for Eucalyptus grandis plantation in Sichuan. [Method] Sixty standard sites were set up to diagnose foliar nutrient status by critical value approach （CVA） ,diagnosis and recommendation integrated system （DRIS） and relative growth rate （RGR）. [Resuit] There were no effects on K,Ca,S,Cu,Zn,Fe and Mn,no signification in biology to P,great influence on the growth of N and B, and creditable result to Mg in diagnosis results by critical value approach. Except that there was error diagnosis in Zn, Fe and Mn, other diagnosis results by DRIS accorded with practice. Diagnosis results by relative growth rate provided high reference value to nutrient management, hereby established foliar nutrient diagnosis standard for Eucalyptus grandis plantation in Sichuan. [Conclusion] According to this research, results diagnosed by critical value was low in validity due to influence of forest age, rainfall, temperature, humidity and alternation among nutrients. DRIS sampling in large number can＇t distinguish nutrient balances of high or low level, while relative growth rate requires less samples and takes into account of trowth potential,so the diagnosis result is more practical,and diagnosis result accords with practice.