Effect Of Plastic Film Mulching And Nitrogen Application Rates On Net Global Warming Potential And Greenhouse Gas Intensity On Spring Maize Cropping Systems In Dryland Farming

A film experiment was conducted at Shaanxi Changwu ecosystem experimental station of Loess Plateau to consider the effect of different nitrogen(N)fertilizer management and film mulching on greenhouse gas emission and net global warming potential.This experiment was conducted to examine the fluxes of nitrous oxide(N2O),methane(CH4),carbon dioxide(CO2)and the equivalent of CO2 emissions from the input of agricultural production from 2016 to 2017,and then calculated the net global warming potential and greenhouse gas intensity under different N management.There were 0 kg ha-1(N1)?100 kg ha-1(N2)?250 kg ha-1(N3)?400 kg ha-1(N4)four N levels respectably inputting in film mulching(FM)and un-mulching(UM)field.N2 O,CH4 and CO2 were collected and measured by static chamber-gas chromatography system in one-year study.The main results are summarized as follows:1)Nitrogen inputting would induce the emission rate of N2 O,for the different nitrogen treatment 0?100?250 and 400 kg·ha-1 under the FM,their emission rate of N2 O is 2.26?7.42?16.58 and 31.08 ug N2O-N m-2 h-1m-2 h-1 respectively.As for the BP,they are 2.39?5.93?17.18 and 23.28 ug N2O-N m-2 h-1 Before the VT period,the emission rate of N2 O under the FM would larger than the BP.2)There is no difference between the FM and BP in the accumulation of N2 O flux.The accumulation of N2 O flux for different nitrogen treatment 0?100?250 and 400 kg·ha-1 under the FM is 0.08?0.26?0.57 and 1.07 kg N2O-N ha-1,and 0.08?0.20?0.59 and 0.80 kg N2O-N ha-1 for the BP.Mulching advance the accumulation of the N2 O flux.3)The increasing nitrogen inputting induce the CO2 emission while do not influence the CH4 emission.Their accumulation flux for the FM and BP are 2.02~3.59 t·ha-1,0.61~0.79 kg ha-1 and 2.14~3.23 t·ha-1,0.87~1.05 kg ha-1.4)The plastic film mulching significantly improve the crop yield: The yield for the FM and BP is 2.0-16.7 Mg ha-1 and 0.9-8.8 Mg ha-1.5)To calculate the various Net-GWP,the emission factor has been developed: The increasing nitrogen inputting would both increase the GWP under the FM and BP,while the FM does not increase the GHGI.We could get the attainable crop yield and reduce the carbon emission by the plastic film mulching implement at the nitrogen rate of 250 kg ha-1.