The results showed that the soil urease activity and (microbial) biomass carbon were restrained significantly, and then, come consistent with CK, and the catalase activity of soil was lightly restrained at first, then stimulated and recovered as the soil treated with iodosulfuron-methyl sodium at a level of 1 mg/kg.
Published data in literatures were used to estimate the effect of crop residue amendment on carbon sequestration in agriculture in the North China Plain. Three aspects were considered in the carbon sequestration calculation including soil organic carbon increase,biomass carbon increase and carbon emission decrease through decreasing chemical N,P,and K fertilization after crop residue amendment.
Through measuring the dynamic transformation of soil microbial biomass C,the turnover of biomass C was 52.69 g/m~2 in a growth season,the turnover time was about 1.25 a.
With the temperature raised, the carbon consumption of microorganism quantity increased with the decomposition speed accelerating and its content decreasing.
Authors believed that the increase of soil microbe amounts and microbe biomass in NCD was the result of high fertilizer and “zero input” pesticides in this treatment.
The main results are in the following: (1) Forest area and forest biomass carbon (C) stock increased from 116.5×106 ha and 4.3 Pg C (1 Pg C = 1015 g C) in the early 1980s to 142.8×106 ha and 5.9 Pg C in the early 2000s, respectively.
Forest biomass carbon density increased form 36.9 Mg C/ha (1 Mg C = 106 g C) to 41.0 Mg C/ha, with an annual carbon sequestration rate of 0.075 Pg C/a.
The size of the microbial biomass carbon and the soil enzyme activities increased with the addition of an amendment and was highest at equal proportions of coal ash and sludge.