坡位对马尾松林下土壤理化性质、酶活性及微生物特性影响

以我国南方花岗岩区退化马尾松林地土壤为研究对象,通过典型样地调查方法研究不同坡位（坡上、坡中,坡底）马尾松对土壤理化性质、酶活性和微生物学性质的影响。结果表明,0～20和20～40 cm土层土壤w（有机质）、w（全氮）、w（碱解氮）和w（速效钾）坡位间差异均显著（p〈0.05）,其中w（有机质）和w（全氮）均表现为坡底〉坡中〉坡上;而w（全磷）和w（全钾）位间差异不显著;3坡位中坡底土壤w（粘粒）较高容重较小。土壤酶活性坡位间差异不显著,可能受林分密度影响较大。两土层微生物生物量碳氮与土壤呼吸强度均为坡底最大,且与有机质和全氮相关性分别达显著（p〈0.05）和极显著（p〈0.01）正相关,但在微生物对碳利用效率、有机碳氮累积程度等方面坡位间差异不显著。所以,对养分瘠薄且易受侵蚀的花岗岩红壤区域,马尾松作为恢复植被须谨慎选择。

Effect of slope position on soil physicochemical properties, enzyme activities and microbial properties in Pinus massoniana plantation

Using the typical plots investigation method,soil of three different slope positions（upper slope,middle slope and base of the slope） in Pinus massoniana plantation area with soil parent material of Granite in southern China were analyzed to study the effects of Pinus massoniana on soil physicochemical property,soil enzyme activities and soil microbial properties.The result showed that soil organic matter,total nitrogen,available nitrogen and available potassium contents were significantly different among three slope positions in both 0-20 cm and 20-40 cm soil depths,in which soil organic matter and total nitrogen ranked as base of the slopemiddle slopeupper slope.Soil total phosphorus and total potassium were insignificantly different among slope positions and the highest soil clay content and the lowest bulk density were both in base of the slope.Soil enzyme activities had no significant difference among slope positions,which were possibility affected by stand density markedly.In both soil depths,soil microbial biomass carbon,microbial biomass nitrogen and soil basal respiration exhibited highest levels in base of the slope which significantly and positively correlated with soil organic matter and total nitrogen contents.However,no significant differences were observed in usage efficiency of soil microbial and cumulative amounts of organic carbon and nitrogen among three study plots.Therefore,we should be cautious when choose Pinus massoniana for restoration in poor and serious erosion red soil area which derived from Granite parent material.