Effect Of Plastic-covered Ridge And Furrow Rainwater Harvesting Systems And Nitrogen Fertilizer Application On N₂O Emission And Water And Fertilizer Use Efficiency Of Spring Maize

N₂O has high global warming potential,and it is the most important greenhouse gas for agricultural soil emissions in arid areas.Mitigating N₂O emissions from farmland is very essential to mitigate climate change.The cultivation of plastic-covered ridge and furrow rainwater harvesting systems?PRFRHS?has developed into a major water-saving irrigation technology in China's arid regions because of its great advantages in promoting arid land crop productivity.In this study,by taken the spring corn field in arid land as the research object,four fertilization modes:no fertilization?T1?,urea-based application?T2?,and urea-based topdressing?T3?and slow-release fertilizer?T4?,were set under the plastic-covered ridge and furrow rainwater harvesting systems?P?and conventional flat planting?C?.To study the effects of rainwater harvesting and nitrogen fertilizers on the emission of N₂O,soil character,crop yield,water and fertilizer use efficiency in spring maize fields.Expected clarify the regulation effect of PRFRHS on soil N₂O emission,and explore a nitrogen fertilizer management measure of stable high yield and reducing N₂O emission under PRFRHS.The main conclusions of this research are as follows:?1?PRFRHS significantly increased N₂O seasonal emissions by 6-19%,but reduced the yield-scaled N₂O emission of maize fields by 4-20%than conventional flat planting.The N₂O seasonal emissions and emission factors of PT4 were significantly lower than those of PT2 by9-36%and 15-34%,respectively,and the yield-scaled N₂O emission of PT4 was significantly lower than that of other treatments by 1-39%.The combined PRFRHS with slow-release fertilizer?treatment PT4?can effectively reduce the amount of nitrogen lost as N₂O forms in fertilizers,and significantly reduce the intensity of greenhouse gas emissions in farmland on the basis of stable production.?2?PRFRHS significantly increased the average soil temperature on the ridges,which was 2.3-5.1°C higher than that of the flat planting,and the warming range weakened with the deepening of the soil layer.Compared with flat planting,the PRFRHS significantly increased the soil moisture in the 0-20cm soil layer.In the months with less rainfall,the water harvesting effect of PRFRHS is mainly reflected in the 0-60cm soil layer,while the soil moisture content in the 80-160cm soil layer is lower than that of the flat soil.This is because under the conditions of drought,spring maize with PRFRHS can make full use of the deep soil moisture.At the grain filling stage,PRFRHS significantly reduced the soil nitrate content in 40-100cm soil layers;under the same planting pattern,the slow-release fertilizer?T4?treatment significantly increased the nitrate content in the soil from 0-80 cm compared compared with the urea-based?T2?treatment.Correlation analysis showed that the N₂O emission flux was significantly correlated with the content of ammonium nitrogen in soil and soil moisture.Soil moisture and nitrogen fertilizer were the main drivers of N2O emission from spring maize fields.?3?The plant height,leaf area index at silking stage,biomass accumulation at maturity stage,nitrogen content in grains,grain yield,crop water use efficiency,and nitrogen partial factor productivity of PRFRHS were significantly higher than those of conventional flat planting by 12-46%,8-17%,19-43%,23-34%,23-47%,18-37%,27-38%,respectively.There was no significant difference between the leaf area index,dry matter quality,grain yield,water use efficiency,and nitrogen partial factor productivity of PT4 and PT3,which was significantly higher than other treatments.The leaf area index at silking stage,dry matter quality at maturity,and Grain nitrogen content,grain yield,water use efficiency,and nitrogen partial factor productivity of PT4 were significantly higher than those of PT1 by 30-41%,33-75%,58-73%,41-67%,36-47%,and 40-71%,respectively.The combination of PRFRHS and slow-release fertilizer base application or urea topdressing can effectively increase the crop yield and the efficiency of water and fertilizer.