The Effects Of Land Use Type On CH₄ Uptake And N₂O Emission In The Farming-pastoral Ecotone Of Inner Mongolia

In this paper, four different sample sites (Including natural grassland and 5,10,15 years farmlands) which located in farming-pastoral zone at Taipusi Banner of Xilinguole League in Eastern Inner Mongolia were taken as the research object. Using the static opaque chamber-gas chromatography, the field observation experiment was conducted to study the seasonal dynamics of soil CH4 absorption and N2O emission from the four sample sites and explore the effects of land use patterns variation to soil CH4 absorption and N2O emission.Based on the field observation and indoor culture experiments,we explored the changing of soil CH4 absorption at the same temperature and different water gradients,when the typical steppe at Taipusi Banner of Xilinguole League in Inner Mongolia changed to farmland.The further research was to find out correlation affecting factors between land use patterns and characteristics of CH4 and N2O gas source and pool of farming-pastoral zone. Furthermore, it could be providing reasonable theoretical basis for forecasting of climate warming and making of measures of greenhouse gas mitigation.The main results are as follows:1. When the land use patterns of farming-pastoral zone in Inner Mongolia changed from natural grassland to farmland, the soil CH4 absorption ability was decreased with increase of tillage period.2. When the land use patterns changed from natural grassland to farmland, the soil N2O emission ability of farmland which were reclaimed for 5 and 10 years were decreased, but after 50 years,the ability was increased,and the cumulated emission of N2O was increased with the increasing of years of reclamation.3. The field observation experiment showed that the main affecting factors of CH4 absorption were soil temperature, moisture content, organic carbon and total nitrogen content.The main affecting factors of N2O emission were organic carbon,total nitrogen content and soil moisture content.4. The incubation experiments indicate that soil CH4 absorption ability was reduced when the natural grassland changed to farmland. It manifested as F50