The Study On Nutrient Degradation And Contribution To Greenhouse Gas Emission Of Grazing Sheep Excreta

This experiment was carried out in stipa breviflora desert steppe of Inner Mongolia in2010and2011. Nylon-weight loss method and static respiration chamber were used to measure nutrient degradation of grazing sheep excreta and their effect on greenhouse gas fluxes, respectively. The results were shown as follows:Summer was the main degradation period of sheep dung in the year around. The contents of dry matter (DM), organic matter (OM), crude fat (CF), neutral detergent fiber (NDF), acid detergent fiber (ADF), nitrogen (N) and carbon (C) of the sheep dung in the soil (5cm) reduced significantly (p＜0.01) during the measured period, whereas degradation rates of phosphorus (P) and calcium (Ca) were not significant. The dynamic changes of the degraded nutrient fitted non-linear regression equation:y=yo+a (1-e-bx). Greenhouse gases fluxes were affected (p＜0.01) by sheep excrete and sampling time during the measured period. Sheep excreta weakened CH4consumption and increased CO2emissions. Nutrient degradation of grazing sheep excreta and their contribution to greenhouse gas emission should be affected by a series of factors, which should implement further investigation.