Harvesting On Soil Carbon Storage And Residue's Carbon Released

Reponses of soil labile organic carbon and residue decomposition dynamics to different harvest methods during 3 years cutting were measured in Maoershan Forest Research Station of Northeast Forestry University. Secondary forests were chosen to be processed in four different cuttings. At the same time, set non-cutting control plot. The results showed:The returns of cutting residues in different treatment were significantly different. Residue return was in descending order:afforestation (forestation after clear cutting), partial cutâ… (50% of the stand volume removed), partial cut II (25% of the stand volume removed), control (uncut),cropland (farming after clear cutting). The range of residues returned to the forest biomass was 35.02-2.81t/hm2. Biomass returning of afforestation was 2.6 times the number of the partial cutâ… ,4.9 times of the partial cut II and 12.5 times of the cropland.The return of carbon in different treatments were significantly different. Carbon returned of residue were in descending order:afforestation, partial cutâ… , partial cutâ…¡, control,cropland. The change was in the range of 15922.39-1275.87 kg/hm2. The variation of carbon returning was similar to the biomass returning.Treatment of different harvesting logging residues during the decomposition of its residues were not significant different, which illustrate that the cutting treatment on the residue decomposition rate did not produce significant effect. Treatment of different cutting branches in the decomposition of logging residues in the C, N, P, K of the residual rate were of no significant difference.The variety of logging residue biomass decomposed was significantly different. Decomposition of return was in descending order:afforestation, partial cutâ… , partial cutâ…¡, control, cropland. Descending order of the carbon returning was the same as the biomass returning. The carbon released of afforestation was 10.8 times of the cropland,4.7 times of the partial cutâ…¡, and 2.6 times of the partial cutâ… . This showed that the residues returned differences of different cutting could cause significant changes of the carbon released.Soil carbon, nitrogen, phosphorus, potassium and carbon density of different cutting did not change significantly during 3 years. However, the carbon density increment was different in 3 years after the cutting processing of different harvesting. Descending order of carbon density increment:afforestation, cropland, partial cutâ… , partial cutâ…¡, control.In 4 harvesting treatment, Soil carbon, nitrogen, total phosphorus content were all in descending order:afforestation,cropland, partial cut I, partial cutâ…¡, control. The descending order of soil kalium was:cropland,afforestation, partial cutâ… , partial cutâ…¡, control.