元谋干热河谷人工林的土壤养分效应及其评价

研究了元谋干热河谷地区人工林对土壤养分的效应,并选择了土壤有机质、全N、速效N、速效P、速效K作为人工林重建对土壤养分效应的指标,运用灰色关联度进行综合评价.结果表明:(1)12年生的桉树、苏门答腊金合欢、新银合欢类人工林土壤表层有机质、全N量其增幅高于10年生、6年生的人工林;除念珠相思林以外,人工林表层土壤有机质含量均高于所在试验点的对照地.混交林对增加土壤表层有机质含量的作用非常明显,其改良能力优于纯林;人工林土壤表层全N含量均低于1.0 g·kg-1;(2)速效N的变化规律与全N含量基本一致,速效P含量波动较大,土壤速效K含量比较丰富,pH值的范围在4.44～6.42之间;(3)灰色关联度分析的结果为赤桉 苏门答腊金合欢混交林对土壤养分的影响相对较大,其关联系数为0.651,影响最小的为念珠相思纯林,关联度系数为0.343.

Effects of Plantation on Soil Nutrient and Evaluation in Yuanmou Dry-hot Valley

This paper selected surface soil organic matter,total nitrogen,available nitrogen,phosphorus and potassium contents to study the effects of plantation on soil nutrient in Yuanmou Dry-hot Valley,then evaluated with grey relational analysis.Results are as below:(1) Surface soil organic matter and total nitrogen contents of 12-year old of Eucalyptus,Acacia glauca,Leucaena leucacephala increased much more than that of other 10-year old and 6-year old plantations.Surface soil organic matter contents of each plantation was higher than that of the control plot.Mixed forests could increase surface soil organic matter contents much more than that of pure forests.Surface soil organic matter contents of all plantations was under 0.1%.(2) The variation of available nitrogen was accordant with total nitrogen content.Available phosphorus content fluctuated much,available potassium content was abundant,pH value ranged from 4.44~6.42.(3) Through grey relational analysis,the E.camaldulensis + A.glauca mixed forest had the most effect on the soil nutrient most with the association coefficient of 0.651.The A.torulosa pure forest got the least with the association coefficient of 0.343.