| Aerated irrigation is to alleviate the drip for a long time led to a lack of oxygen to the roots of the problem and the agricultural irrigation technology research,at present,the aerated irrigation has proved to effectively improve the soil air permeability,and increase crop yield,quality and water use efficiency,and more research reveals the water,fertilizer,gas under the condition of single factor or two factors coupling farmland soil CO2 and N2O and CH4 emission characteristics,but at the moment about the water-fertilizer-air coupled ecological effect is not clear.This study is selected crops with tomatoes,aerated condition consists of low,medium and high three water level?0.6 W and 0.8 W and 1.0 W,W represents the amount of irrigation when fully irrigated?and low,medium and high(120,180 and 240 kg·hm-2)three nitrogen levels,unaerated full irrigation to control processing,twelve treatments were contained,greenhouse tomato were studied dynamic change characteristics of soil CO2 and N2O and CH4,the variation characteristics of soil environmental factors?temperature,soil moisture,soil NO3--N content,oxygen content and soil microbial quantity?,tomato biomass yield,quality and water use index?irrigation water use efficiency and nitrogen use efficiency?.Discuss the applicability of water-fertilizer-air coupled in greenhouse tomato fields in northwest semi-humid arid area.The combination of technical parameters under the coupling condition of water-fertilizer-air coupled in aerated irrigation was proposed from the perspective of production increase,quality and emission reduction.The main conclusions are as follows:?1?Soil CO2 emissions were increased by irrigation,nitrogen application and aeration.The cumulative CO2 emissions of the high-water treatment soil increased by 7.1%and 10.3%respectively compared with the middle irrigation and low irrigation,the cumulative CO2emissions of the high-nitrogen treatment soil increased by 3.1%and 9.7%compared with the middle nitrogen and low nitrogen treatment soil,and the cumulative CO2 emissions of the aerated irrigation treatment soil increased by 6.5%compared with the unaerated irrigation.In the tomato growing season,irrigation,nitrogen application and aeration all caused an increase in soil N2O emissions.The cumulative N2O emissions in the high irrigation treatment soil increased by 19.4%and 55.7%,respectively,compared with the middle irrigation and low irrigation treatment.The cumulative N2O emissions in the high nitrogen treatment soil increased by 12.8%and 42.6%,respectively,compared with the middle nitrogen and low nitrogen treatment.The cumulative N2O emission of aerated treatment increased by 11.2%compared with that of unaerated irrigation.During the growing season of tomato,soil CH4 emission was increased by irrigation and nitrogen application,and increased by aerated.The cumulative CH4 emissions in the high irrigation treatment soil increased by 7.8%and 18.3%,respectively,compared with that in the middle-irrigation and low irrigation treatment.the cumulative CH4 emissions in the high nitrogen treatment soil increased by 24.3%and 35.0%compared with that in the middle nitrogen and low nitrogen treatment soil.The cumulative emission of CH4 increased by 124%compared with that of unaerated treatment.?2?With the increase of irrigation water,WFPS,the number of nitrifying bacteria and the number of denitrifying bacteria increased,the IWUE decreased,and the nitrogen fertilizer utilization efficiency increased.With the increase of nitrogen application,soil temperature,oxygen content,NO3--N mass fraction,the number of nitrifying bacteria and denitrifying bacteria increased,IWUE increased,and the utilization efficiency of nitrogen fertilizer decreased.Compared with the unaerated treatment,the oxygen content,NO3--N mass fraction and the number of nitrifying bacteria in aerated treatment increased,IWUE increased,and nitrogen fertilizer utilization efficiency increased significantly.?3?The fluctuation of soil CO2?N2O?CH4in tomato field showed seasonal changes.Soil moisture,temperature and oxygen content are the main controlling factors of soil CO2emission in greenhouse tomato field.Soil moisture,temperature,NO3--N content and oxygen content are the main controlling factors affecting soil N2O emission.Soil moisture,temperature and NO3--N content are the main controlling factors affecting soil CH4emission.?4?Under aeration condition,the increase of irrigation amount,nitrogen application amount and aeration increased tomato yield,fruit quality and dry matter accumulation.The tomato yield in the high irrigation treatment soil increased by 14.9%and 29.9%compared with that in the middle irrigation and low irrigation treatment,respectively;the tomato yield in the high-nitrogen treatment soil increased by 9.6%and 27.0%compared with that in the middle-nitrogen and low-nitrogen treatment,and the tomato yield in the aeration soil increased by 10.9%compared with that in the unaeration treatment.Considering the indexes of yield,CO2?N2O?CH4 cumulative emissions,quality,the entropy weight method is adopted to comprehensively evaluate the results.This study recommends aerated high nitrogen sufficient irrigation treatment?W3F3O?as a better irrigation mode.The research results can provide a reference for water saving,production increase and emission reduction of vegetable plots in facilities. |
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