施肥对印楝人工林生长及土壤肥力的影响

以3年生印楝人工林为研究对象，对该林分所在的林地进行施肥试验，设置了9个施肥处理和一个不施肥对照，运用当年树高和胸径生长量、土壤养分和生物指标讨论了施肥对干热河谷印楝人工林生长及土壤肥力的影响。结果表明:(1)3年生印楝人工林树高和胸径生长对施肥的反应存在差异，方差分析和多重比较表明,单施氮肥(处理1、处理2、处理3)和混合施肥(处理7、处理8、处理9)的当年胸径生长量均与对照处理差异显著，而当年树高生长量差异不显著；(2)合理施肥不仅可改善土壤酸碱性和土壤微环境，增强土壤酶活性和提高土壤微生物数量，还可提高林地土壤肥力，防治印楝人工林地力衰退；(3)不同施肥处理对林地土壤肥力的影响不同，氮、磷肥混施是提高林地土壤肥力综合指数最好的施肥方式。

EFFECTS OF FERTILIZATION ON GROWTH AND SOIL FERTILITY OF AZADIRACHTA INDICA PLANTATIONS

Fertilizers were applied in areas with a 3-year plantation of Azadirachta indica in Yuanmou dry hot valley(in Yunnan Province). In this experiment,nine experiments with different combinations of fertilizers and a control were set up in order to study the effect of fertilization on the growth and soil fertility of Azadirachta indica plantation.We analyzed the annual growth of height and DBH,soil nutrient and soil bioindicator.The responses of height and DBH variation to fertilizers were different,and the variance analysis and multiple comparison showed that the growth in heights in single application of nitrogenous fertilizers(treatments 1,2 and 3) and in mixed application of organic fertilizers and chemical fertilizers(treatments 7,8 and 9) was remarkably different from that of the control within a 3-year plantation.But there was no difference observed in height growth among all treatments within a 1-year plantation.It is concluded that scientifically fertilization not only improves soil pH and soil microenvironment,strengthens soil enzyme activities and increases the quantity of soil microorganisms,but also increases the soil fertility,and prevents the degradation of soil fertility.The value of integrated soil fertility index of forest was affected by different treatments of fertilizer application,with the mixed application of nitrogenous fertilizer and phosphate fertilizer being the best for improving the integrated soil fertility index of forest.