The Study On The Characteristics Of Nitrogen Transformation During The Livestock Dung Decomposition In Inner Mongolia Typical Steppe

From June, 2008 to September, 2009, two treatment processes which were artificial placing on the ground and buring in ground were used to trace and measure transformation characteristics of nitrogen forms of grazing livestock (cattle, horse and sheep) dung in decomposition process in Baiyinxile Ranch of Xilinguole League, Inner Mongolia. The main results were as follows:1. The order of total nitrogen content in 3 kinds of fresh livestock dung was sheep> cattle> horses dung. With the extension of decomposition, total nitrogen had no significant change among the three kinds of dung. Nitrogen content of subterranean disposal was higher than land disposal in horse and sheep dung, while there had no significant change in cattle dung under the two disposals.2. The order of alkali-hydrolyzable nitrogen content in 3 kinds of fresh dung was sheep> cattle> horse dung. Change trend of alkali-hydrolyzable nitrogen content was similar to total nitrogen content change, with no significant change. Relatively speaking, alkali-hydrolyzable nitrogen content accounted for only about 12% of total nitrogen content. Alkali-hydrolyzable nitrogen content of subterranean disposal was higher than land disposal in horses and sheep dung, while there had no significant changes in cattle dung under the two disposals.3. The order of organic nitrogen components content was different in 3 kinds of fresh dung, the content of ammoniacal nitrogen, ammonia and amino sugar nitrogen and acid-insoluble nitrogen was sheep>horses>cattle dung; the order of hydrolyzable total nitrogen content was sheep > cattle> horses dung; the order of amino acid nitrogen content was cattle> sheep> horses dung; the order of amino sugar nitrogen content was horses>sheep>cattle dung. The content of ammonia nitrogen, ammonia and amino sugar nitrogen and acid-insoluble nitrogen varied largely in the initial decomposition, and keep at a relatively low level with the extension of decomposition; with the extension of decomposition, the changing magnitude of hydrolyzable total nitrogen content was not large; amino nitrogen content showed a significant trend of decrease, and the change of amino sugar nitrogen content was rather complicated. In the decomposition process, ammonia nitrogen, ammonia and amino sugar nitrogen content of subterranean disposal was higher than land disposal in the three kinds of dungl; the hydrolyzable total nitrogen, amino acid nitrogen and acid-insoluble nitrogen contents of subterranean disposal was higher than land disposal in horses and sheep dung, while there had no significant differences in cattle dung. Amino sugar nitrogen is special, which content of subterranean disposal was higher than land disposal in sheep and cattle dung, while horses dung had no significant differences4. The order of ammonium nitrogen content was sheep>horses>cattle dung, .the order of nitrate nitrogen content was cattle>horses>sheep dung. With decomposition extension, inorganic nitrogen content of the three kinds of dung showed an overall downward trend, but increased significantly in plants growing season. Inorganic nitrogen content of the three kinds of dung were not significant different during decomposition in different disposals.5. Organic nitrogen was the main existing form in grazing livestock dung, mineralization and elution processes were slow. by comparison, horses dung had a relative fast rate of nitrogen release .For the majority of components content and total nitrogen, the disposal of buring in underground resulted in significant increase of its content.