关键词: 土壤团聚体, 稳定性, 土壤有机碳, 生态系统, 峡谷型喀斯特

Abstract: Absorption,accumulation and distribution of Pb,Cd,Cr,Cu,Mn,Ni,Zn,P and S elements in loblolly pine plantation in the hilly regions of southern Jiangsu province were studied.The results show that the storage of nine elements in the soil of the forest is in order of S>P>Mn>Zn>Cr>Cu>Pb>Ni>Cd,their contents in different organs of trees are quite different,being Pb 0.96～5.81,Cd 0.266～0.720,Cr 8.55～9 49,Cu 4.36～9.44,Mn 18.98～61.07,Ni 1.74～9.03,Zn 13.44～32.69,P 168～987,and S 446～1770(mg·kg^-1).Their accumulation ratios of elements in plants are in order of Cd >P>S>Cu>Zn>Cr>Pb>Ni> Mn.The accumulation amounts of Pb,Cd,Cr,Cu,Mn,Ni,Zn,P and S in the biomass of the community are 36.30,5.47,85.58,74.54,248.1,26.81,236.5,3268,and 8158 (mg·m^-2),respectively,of which the overground part accounted for 5.37%,10.60%,23.77%,15.99%,16.61%,12.38%,12.34%,24.85%,and 4712%,higher than underground part.The biological cycles of the elements in the community are described as follows:annual uptake is Pb 23.75,Cd 1.97,Cr 24.07,Cu 27.44,Mn 170.17,Ni 19.51,Zn 109.29,P 1721.69,and S 2843.14 (mg·m^-2).Annual return is Pb 12.70,Cd 0.68,Cr 1.66,Cu 10.49,Mn 70.72,Ni 6.46,Zn 40.60,P 257.61,and S 486.56 (mg·m^-2).The turnover periods of nine elements are 3,8,52,7,4,4,6,57 and 17 years respectively.

Key words: soil aggregate, stability, soil organic carbon, ecosystem, karst canyon region.