Dry Farmland Greenhouse Gases Emission Characteristics And Its Influencing Factors Of Corn Fields Under Different Cultivation Model On The Loess Plateau

There are a large number of studies have reported on effects of different cultivationmodes especially mulching fields on soil water use efficiency, crop yield, and soil biologicalproperties, but reports on impact of soil greenhouse gas emissions on farmland are verylimited. In view of the above problems, In2012, taking Dryland Spring Corn of LoessPlateau as the object of study, we use the static chamber-gas chromatography technique tomonitor N₂O, CO₂and CH₄emission of corn field under different cultivation in Changwuagro-ecological station. in order to explore the effects of mulching and nitrogen fertilizer, aswell as Factors of water, temperature and soil microbial biomass etc. on greenhouse gasemissions, providing theoretical basis and data reference for reducing greenhouse gasemissions, and provide certain reference for improve the utilization of n fertilizer andreduction of greenhouse effect. The results obtained were summarized as follows:1. Nitrogen application is main factor to affect the N₂O emissions. High nitrogentreatment> high efficient treatment> no N fertilizer treatment, and emissions peaked in4-10d after fertilization, N₂O flux of nitrogen treatments was presented seasonal dynamics,three emission peaks in all, emerged after nitrogen fertilizer application and rainfall.Mulching and sand covering treatment did not significantly affect N₂O emissions underequivalent fertilization condition. The correlation between N₂O emission and soil NO₃^-wasvery positively significant （p <0.01）.2. CO₂emission has obvious seasonal dynamics in the whole growth period of corn,CO₂emissions are higher in summer, lower in spring and autumn. Analysis of varianceshowed that comparing with no mulching treatment, mulching and sand covering treatmentsdid not significantly increase CO₂emissions. The application of organic fertilizer couldsignificantly promote the CO₂emission, The result also showed that temperature and soilmicrobial biomass C are the main factors to influence CO₂emission.3. The values of different treatments’ CH₄emission from this study were minus, whichmean that during the whole growing season of spring corn, the soil was a net sink ofatmospheric CH₄. With exception of no mulching treatment, in which absorption of CH₄in soil was significantly higher than the other treatments, there was no significant differenceamong the rest treatments. And compared with no nitrogen fertilization, fertilization did notsignificantly increase CH₄absorption. The temperature condition significantly affect CH₄emission; Higher soil moisture content go against CH₄oxidation （absorption） in soil, whilethe temperature is higher, it is in favor of CH₄oxidation （absorption） in soil.The preliminary results show that in the dryland of Loess Plateau, mulching didn’tincrease emission of N₂O、CO₂and CH₄under proper nitrogen fertilizer. While overusenitrogen fertilizer, it will increase N₂O emission significantly, application of organic fertilizerwill increase CO₂emission, but application of nitrogen fertilizer almost had no obvious effectto CO₂emission. Higher soil moisture content go against CH₄oxidation （absorption） in soil,while the temperature is higher, it is in favor of CH₄oxidation （absorption） in soil.