关键词: 土壤酶活性, 肥力指标, 苏南地区

Abstract: Investigations were carried out on activities of soil urease,sucrase and acidic phosphatease in soils under four different forest stands,i.e.Pinus massoniana,Phyllostachys pubescens,Quercus acutissima,and Cunninghamia lanceolata,and their relationships with soil physical and chemical properties in the south part of Jiangsu Province.Results indicate that the soil under Pinus massoniana is the highest in activity of sucrose and acidic phosphatease,the soil under Phyllostachys pubescens the highest in activity of urease,while the soil in bare land is the lowest in activity of all three enzymes.In soil profiles,enzyme activity declines gradually from top to bottom,and variation is obvious with soil sucrase and acidic phosphatase and not so with soil urease.The analysis of correlation indicates a significant positive correlation of soil sucrose and acidic phosphatease with soil total nitrogen,available phosphorus,and organic matter,separately,at the level of α=0.01,and with each other,at the same level,too;of soil sucrose with Pb at the level of α=0.05;of soil acidic phosphatease with Cu,and Pb at the level of α=0.01,of urease with Pb,soil total phosphorus and organic matter at the level of α=0.01 and with total N,acidic phosphatease and Cu at the level of α=0.05,but a significant negative correlation with soil bulk density.The regression analysis reveals that the three enzymes have a non-linear correlation with soil total nitrogen,available phosphorus,organic matter,Cu,and Pb.The principal component regression analysis indicates that the primary factors of soil fertility are soil total nitrogen,organic matter,available phosphorus,available K,urease,sucrase and acidic phosphatase.The three soil enzymes are the perfect indicators for soil quality assessment.

Key words: soil enzyme, fertility index, south area of Jiangsu Province