Transformation Of Exogenous Nitrogen To Soil Amino Acids At Different Temperature

The black soil area in northeast China is the supply area of high quality commodity grain.Under the background of high agricultural production integration,the black soil degradation is serious and how to improve the production efficiency of land through reasonable fertilization has become an important issue.Northeast black soil area is located in the northern temperate semi-humid monsoon climate zone,the temperature span,the climate characteristics of agricultural production have a great impact.Nitrogen is a very demanding element in the process of crop growth and is a limiting element of crop growth rate and growth.In view of how to improve the utilization rate of nitrogen fertilizer,some research has been carried out in the black soil area of Northeast China.However,the deep mechanism of soil nitrogen transformation and utilization under environmental changes is still unclear,especially how the temperature changes affect soil nitrogen microbes Assimilation process is still a vague problem.According to the climatic characteristics of the northeast,five temperature gradients,20%constant soil water content,plus straw and no straw were set at 5^oC,15?,25? and 35?.The contents of amino acids and the ratio of isotope enrichment in soil samples were determined by liquid chromatography/mass spectrometry?HPLC/MS?,and the carbon dioxide flux and temperature sensitivity index were calculated.The aim of this study was to investigate the effect of temperature on the conversion of inorganic nitrogen to amino acid.The following conclusions are drawn:?1?Under 25?,inorganic nitrogen was most easily converted to soil amino acid.With the incubation time,the assimilation rate increased first and then decreased.?2?Under the condition of 25? without substrate treatment,the CO₂ flux was the largest,indicating that the soil microbial activity was the strongest at 25?.?3?After adding the straw,the higher the temperature,the easier the decomposition of the substrate,the more carbon substrate into the soil,so that the inorganic nitrogen to the soil amino acid conversion.The synergistic effect of carbon and nitrogen makes the soil nitrogen more easily in the form of soil amino acid.