Soil Organic Matter And Wheat Straw Decomposition And Simulation Under Different Temperature And Moisture Condition

Soil organic matter and wheat straw decomposition were studied through indoor incubation experiments under different temperatures and moistures. The mechanism of Soil organic matter and wheat straw decomposition were discussed through the accumulated CO2, microbial biomass and inorganic nitrogen content. According to the public models, the model parameters and sensitivity were analyzed.The main concludes were as follows:Temperature and moisture had effects on soil organic matter and wheat straw decomposition. The accumulative CO2 released during wheat straw and soil organic matter decomposition increased when temperature rise from 15℃ to 35℃ and moisture from 30% to 100% respectively. Wheat straw residue decomposed by 50% under temperature 35℃ and 100% relative moisture. Soil organic matter decomposed 893.5 mg kg -1.The accumulative CO2, microbial biomass and soil inorganic nitrogen content were different during soil organic matter or wheat straw decomposition under different temperature and moisture condition.It was distinct that the temperature and moisture effects on soil organic matter decomposition were different from wheat straw. Using the temperature effect function developed by Johnsson in 1987, Q10 of soil organic matter decomposition were 1.34. Q10 of the wheat straw residue decomposition was 1.23.Moreover different functions were used to describe the temperature and moisture effects on soil organic matter and wheat straw decomposition. It was the better to use Gaussian function for the temperature effect on soil organic matter decomposition. The moisture effect function on soil organic matter and wheat straw decomposition could refer to functions developed by Quemada and Johnsson respectivelySoil microbial C/N decreased as inorganic nitrogen was added to soil. The inorganic nitrogen was immobilized by soil micro-biomass. The wheat straws decomposition could immobile the more inorganic nitrogen. There was not distinct different in the accumulated CO2 that released between soil organic matter or wheat straw residue decomposition with or without added inorganic nitrogen.Simulation models were used to analyze the experiment data. The model parameters were obtained. The mean square errors were different. The model developed by Nicolardot in 2001 should be recommended. Using the models to analyze the soil organic carbon and nitrogen transformation. The conclusion obtained at the experiment could be explained.