The Composition and Organic Carbon Distribution of Organo-mineral Complex in a black Soil as Influenced by Land-use Change and Long-term Fertilization
The aim of this experiment was to examine the impact of natural vegetation restoration and long-term fertilization on the composition and organic carbon distribution of organo-mineral complexes in a black soil. The results showed that the fine sand-size complex was the dominant particle of different size complexes. Contents of silt-size and fine sand-size complexes increased in the NP and NP plus animal manure (NPM) treatments, while the content of clay-size complexes decreased as compare with the non-fertilized treatment (NF). The contents of silt-size and clay-size complexes in the grassland (GL) and the bare land (BL) were the same as that in NF. Landuse change resulted in different dynamics in C sequestration in soil, which made cumulative CO2 emissions differ significantly among the five treatments during the growing seasons. The content of <20 μm size complex in GL was more than those in NP and NPM. The GL has a potential of sequestering more C than tilled soils due to the stability of SOC stored in the <20 μm size fraction. The cumulative CO2 emissions increased in the order of NP < GL < NPM. Long-term application of organic manure and vegetation restoration increased the organic carbon content of all sizes of complexes, but increased the cumulative CO2 emissions. Nevertheless, these soil management practices have substantially increased C sequestration into the soil rather than net C losses.
KeywordsOrgano-mineral complex Land use SOM Carbon sequestration CO2 emission
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