The Effects Of Land-use Change On The Soil Organic Carbon

Global climate change and its impacts on the earth are one of the most severe problems which human face. The critical issue is the changing pattern of carbon cycle and its reasons. The soil organic carbon pool is the largest carbon storage pool in the terrestrial ecosystem, which plays an important role in accommodating climate and effecting climate. Human activities on the carbon pool of terrestrial ecosystem and changing pattern of the fossil carbon pool are ultimately the causes of the climate change. The land-use change is the main human activity, which effects the global environment and has an influence on the global climate change. To scientifically learn the effects of land-use change on soil organic carbon is the key for us to understand and solve the climate change problem.The paired plots with the same elevation, the slope degree and the soil type of the secondly natural stands, artifical stands, shrubs and arable lands were selected as study objects in subtropical areas in Fuyang county, Zhejiang province. Based on the field survey, field orientation study and laboratory analyse and by means of comparison of difference of input, output and storage of organic carbon among different land-use types, the effects of conversion of the secondly naturally stands into artifical stands, shrub, bamboo stands, tea land and arable land, and changes in soil organic carbon after bamboo afforestation in cropland were studied in this thesis. The carbon source or sink of different land-use types were estimated and some measures to increase the carbon sequestration were put forward finally.The land-use change impacts the storage of living biomass carbon, debris carbon storage and their decomposition rate. The storage of living biomass carbon of the naturally secondly stands, artifical stands, and arable land are 50.18 t.hm^-2, 27.74-14.08 t. hm^-2, 2.19 t. hm^-2 respectively. This showed that if the naturally secondly stands were conversed into artifical stands, the storage of living biomass carbon would keep a definite level, but if conversed into arable land, the storage of living biomass carbon would be decreased greatly. The storage of the living biomass carbon from highest to lowest ranked as follows: the naturally secondly stands, Chinese fir, masson pines, intensive maozhu stands, extensive maozhu stands, shrub, zhaozhu, tea land and arable land.