Effects Of Salinity, PH, Nitrogen Ferilizer On Saline Alkali Soil N₂O Emission

The study site is located within Hetao irrigation area in Bayannur City, in the west of Inner Mongolia. The saline-alkali soil, serious saline-alkaline soil, and light saline-alkaline soil was chosen as the object of study. A indoor incubation experiment was conducted to study N2O emission characteristics, and influence of Salt content, pH, Nitrogen fertilizers on N2O emission characteristics in different saline alkali soil, with the same conditions of water content and temperature. The results are beneficial to identify the factors which influence the emission of N2O of saline-alkaline soil, and can provide dataset support to estimate the model of emission of N2O of saline-alkaline soil. The main results are as following:1. In this experiment, N2O emission rate and cumulative emissions are saline-alkali soil> serious saline-alkaline soil> light saline-alkaline soil. The soil N2O emission has a significant correlation with soil salt content, pH value, content of nitrate nitrogen, content of ammonium nitrogen.2.The salt content of9degrees including0.1%,0.2%,0.4%,0.8%,1.6%,1.7%,2.4%,3.4%, and5.0%was designed, when the salt content is lower than1.7%, the salt can promote the N2O emission, and when the salt content is higher than1.7%, the salt can restrain the N2O emission. The relationship between the cumulative emissions of N2O and the salt content can be fitted by quadratic equation. The rising salt content of soil can cause reduce of the content of soil ammonium nitrogen and increase of the content of nitrate nitrogen.3. Under5different pH series (pH=5.0,6.0,7.0,9.0,12.0), higher pH from saline-alkali soil, serious saline-alkaline soil, and light saline-alkaline soil has a same effect on emission of N2O. It is much easier to produce N2O in alkaline soil. The emission of N2O saline-alkali soil with a higher salt content and pH is higher than light, serious saline-alkaline soil. The rising of pH can result in reduce of the content of soil ammonium nitrogen and increase of the content of nitrate nitrogen.4.4kinds of nitrogen content (0、0.1mg/g、0.2mg/g、0.4mg/g) were incorporation to three different kinds of saline-alkaline soil, the N2O emission increased. The soil N2O emission after fertilizer application is higher than the soil which is not applied fertilizer, and N2O emission which has more nitrogen rate is higher than the soil that has less nitrogen rate. The rising of nitrogen content can lead to the increase of the content of soil ammonium nitrogen and nitrate nitrogen.