The Effect Of Different Land Use Types On The Physical And Chemical Properties Of Soil And The Function Of Ecological Service In Changsha City

This study selected five main kinds of land use (agricultural-Land, forest-Land, grass-land, construction green-land and unutilized-land) in Changsha city as the research object, According to Forest ecosystem service function evaluation specification and land use status data, combining the field investigation laboratory analysis, discussed the correlation between soil physical and chemical properties, calculated ecosystem service function(water conservation, soil conservation, carbon sequestration, purify atmosphere) value of Changsha in 2013, the results could provide basis for Changsha urban land use management and planning, and also for making ecological compensation mechanism. It can promote the ecological environment construction, to realize the win-win of land use in the aspects of economic, ecological and social benefits. The results showed that:(1)In different kinds of land use soil physical and chemical properties, each kinds of land use but grass-land, the soil nature moisture content was increased with the increase of depth, and the trend is opposite with soil bulk density, capillary porosity and gross capillary porosity changing trend. The differences between different kinds of land use on same layers were significant(P<0.05). the soil of Changsha presented as Acidic or alkaline. Soil’s total N, total K, total P stayed in the low level, and also presented lower trend along with the depth. Certain difference exits each level. On the horizontal distribution, except the artificial fertilizer farmland(P<0.01), every land use has no significant difference on soil total N, total K and total P content. Five types of land use soil’s C/N value is between 2.12-21.21, forest-land and grass-land’s C/N value is much higher than other types of land.(2)In each of the indicators, there is a negative correlation relationship(P<0.05) between natural moisture content and bulk density, bulk density,total K, pH and SOC. Between the natural moisture content and bulk density, pH and SOC, there is exist significantly negative correlation(P<0.01). And natural moisture content has significant positive correlation(P<0.01) between total N, total P, and total K. The relationship also exists between total N and total P, total K; Total P and total K. In the different ways of land use, The agricultural natural moisture content has a significant negative correlation relationship(P<0.01) with soil bulk density. Soil SOC and total N, total P were in extremely significant positive correlation(P<0.01). The grassland soil SOC and total N, total K; Total N and total K were in a significantly positively related relationship(P<0.05). And total N has significant positive correlation relationship (P<0.01) with total K. Natural moisture content and total N, total P was in a significantly negative correlation relationship(P<0.05) between grassland and construction land. The total N and total P appears significant positive correlation(P< 0.01).(3)Due to the effect of artificial and natural factors at different aspects, Led to difference of ecological service value per unit area of different mode of land use. Value ranking for water conservation:forest-land> agricultural-land> grass-land> construction green-land>unutilized-land;in soil fixing:agricultural-land>forest-land >construction-land> grass-land> unutilized-land;in carbon fixation:forest-land> grass-land>agricultural-land>construction-land>unutilized-land; in air purification: forest-land> construction-land> agricultural-land> grass-land> unutilized-land; The total value:forest-land> agricultural-land> construction-land> grass-land> unutilized-land.(4)Changsha city ecological system has great ecological value, about 133.74×108 Yuan. In the total value, water conservation’s value is 76.07×108Yuan; soil conservation’s is 22.87×108Yuan;carbon fixation’s is 12.43×108 Yuan; air purification’s is 22.46×108 Yuan. The proportion of them is 56.88%、17.03%、9.29%、 16.80%. Water conservation’s value in one unit area is 7172.72 Yuan/hm2, soil conservation’s is 2147.52 Yuan/hm2, carbon fixation’s is 1171.96 Yuan/hm2, air purification’s is 2118.10 Yuan/hm2.