Response Of Greenhouse Gas Emissions To Precipitation Under Different Management Measures In Dry Farming System

Precipitation change is one of the important factors affecting soil in greenhouse gas emissions,and different management measures,such as straw mulching,fertilizer application and crop planting also on farmland soil in greenhouse gas emissions have certain effect,to understand different management measures to drop water on farmland soil,the impact of greenhouse gases,this study conducted a summer fallow period of potted simulation precipitation and growth period of wheat crops simulated rainfall,using the static box—gas chromatography to greenhouse gases(CO2,CH4,N2O)of different management measures to the corresponding response rule of the decline in water research,the main results were as follows:1)through potted precipitation test and.growth period precipitation test,found that the low moisture content,soil respiration and N2O are characterized by low emissions,and CH4 is characterized by being absorbed.Precipitation can effectively promote the soil respiration,but also to soil by CH4 sink into the source of the trend of CH4,precipitation and can also promote the soil denitrification,promote the N2O emissions.But different precipitation on three kinds of greenhouse gases affect differently,on the whole,precipitation is low(0-8 mm),three kinds of greenhouse gases will peak emissions within 1-4h,and the high precipitation precipitation can produce obvious delayed effect emission peak.2)in the potted plant growth period precipitation test and found that soil respiration during the precipitation are associated with soil temperature has significantly,only when the low moisture content,soil temperature is the main control factors of soil CO2 emission rate,temperature and moisture in the soil moisture content is higher common influence the rate of soil respiration;For N2O,low water content of soil N2O emissions from soil temperature has obvious relationship,but after the increased precipitation,N2O emissions from soil moisture and temperature is more complex,also need to be further explored.3)pot experiment showed that the different soil treatment have different impact on the soil in greenhouse gas emissions.Straw mulching can promote soil CO2 and N2O emissions;In low rainfall,straw mulching on soil CH4 emissions has a weakening trend,with the increase of rainfall,the trend will be offset with the rising of water,which shows to promote CH4 emissions,namely in the high precipitation,CH4 emission of the main influencing factors for water,but emissions are still below with no straw mulching treatment.At the same time,nitrogen has reduced soil CO2 emissions,reduce the temperature sensitivity of soil respiration,greatly increases the trend of N2O emissions,but had no significant effect of CH4 emission.Comparison of three kinds of greenhouse gas emissions,under different rainfall water under the condition of nitrogen would greatly increase the N2O emissions,and trend of emissions of CO2 and CH4.4)growth period two rainfall test showed that the high precipitation process will be different levels of soil out of greenhouse gases peak time delay:0-16 mm precipitation of soil respiration in the 4h to reach the maximum,and 32 mm high precipitation processing will be delayed 4h.The peak regularity of CH4 and CO2 are similar,0-8 mm of precipitation after 4h,8h after 16 and 32 mm precipitation;For N2O,precipitation for the appearance of the peak time of 0 to 8 mm rainfall soil N2O emission maximum value appeared in 8 hours,and 16 mm for 12 to 24h,32 mm for 48 hours.At the same time,repeatedly dry-wet alternate can reduce CO2 and N2O emissions,promote the release of CH4.