林木施肥的有效立地指数区间与目标肥效

应用“八五”国家攻关课题“主要工业用材林施肥技术研究”及前人的研究成果，论证和确定了林木有效施肥条件和肥效目标.我国杉木施肥的有效立地指数区间为10,18]；林木施肥的最佳经济效益目标增量与立地指数和单位产出价值成正相关，与不施肥的产量、优势木的平均养分浓度及单位投入价值成反相关；在自然上壤肥力状况下，氮磷钾均为高目标肥效的限制因子．

Effective Site Index Range and Target Fertilization Efficiency of Forestry Fertilization

The present study aims at demonstration and determination of the conditions and targets for effective forestry fertilization using experimental results obtained from the sib Five-year National Key Project "Research on Forestry Fertilization Techniques for Industry Orientated Timber Production". In accordance with the principle of fertilization efficiency, the effective site index range for fertilization in China-fir forests was found to be approximately between 10 and 18. Combination of nitrogen, phosphorus and potassium treatment gave optimal tree growth for China-fir, caribbean and masson pine in different regions in Guangdong and Fujian Provinces, indicating that all these three nutrient elements are limiting factors at natural fertility levels when aimed at high-yield targets. The optimum profits target yield given by the developed forestry fertilization model is positively related to site index and unit output value,but negatively related to average forest growth before fertilization,average nutrient concentrations in dominant trees and unit input value.