Effect Of Nutrient Management On Nitrogen-containing Gas Emission And Yield And Quality Of Greenhouse Vegetable

In recent years,the demand for vegetables in China has increased rapidly.In order to achieve high yields,the excessive application of nitrogen fertilizers in greenhouse production results in higher nitrogen loss,more serious environmental pollution and lower nitrogen use efficiency.Strictly control the application rates of nitrogen fertilizer is essential to reduce pollution and increase nitrogen use efficiency.Therefore,taking tomoto and cumuber as experiment vegetables,according to the"4R"nutrient management concept,experiments were designed with different fertilizer application rates,fertilizer types and application methods.This paper investigated and screened out the management practices,which can reduce the nitrogenous gas emissions and ensure the yield and quality of greenhouse tomato and cucumber production.The following treatments were adopted:No fertilizer（CK）,Organic fertilizer（TO）,Combined organic fertilizer and urea（COU）,Combined organic fertilizer and urea reduced by 20%（80%COU）,slow release fertilizer reduced by 20%（80%SU）,Combined organic fertilizer and urea with NBPT（COU+NBPT）,Combined organic fertilizer and urea reduced by 20%+NBPT（80%COU+NBPT）,Combined organic fertilizer and slow release fertilizer（COSU）,Combined organic fertilizer and Slowrelease fertilizer reduced by20%（80%COSU）,Base fertilizer furrow application reduced by 20%（80%COU+F）.The results of the study are as follows:Reduced fertilizer,slow release fertilizer,urease inhibitors,organic fertilizer,and deep application of fertilizer all have significant emission reduction effects compared with the traditional fertilization（COU）.The average ammonia volatilization flux of each treatment throughout the 2018spring tomato season is ranked as COU>COU+NBPT>80%COU+NBPT>80%COSU>COSU>TO.The average ammonia volatilization flux of each treatment during the entire 2019 spring tomato season is ranked as follows:COU>80%COU+F>80%COU>80%COU+NBPT>TO>80%SU.The order of the average ammonia volatilization flux of each treatment in the whole growing season of the cucumber in 2018 is COU>COSU>TO>COU+NBPT>80%COSU>80%COU+NBPT>CK.The order of the average ammonia volatilization flux of each treatment in the whole growing season of the cucumber in 2019 is 80%COU+F>COU>TO>80%COU>80%COU+NBPT>80%SU.The highest loss of nitrogenous gas was N₂O.The emission factors of N₂O,NH₃,NO and NO₂ranges from 0.46%to 2.85%,0.00%to 0.70%,0.04%to 0.80%and 0.00%to 0.36%,respectively.Application of slow release fertilizers,the addition of urease inhibitors,and reduced fertilization rate have significant effects on reducing N₂O and NO emissions.The nitrogen application rate and soil temperature are the two most significant factors affecting N₂O,NH₃ and NO_X emissions.The amount of nitrogen fertilizer applied has the most inportant contribution to N₂O,NH₃ and NO_X emission fluxes,which are 35.3%,49.6%and 56.5%,respectively,followed by soil temperature,which contributes 21.4%,20.5%and 35.2%.The impact of treatments on tomato and cucumber yields was not significant.The effects of treatments on total amount of sugar,total acid,soluble solids,and Vc of tomato and cucumber were not significant.The"4R"management technology can maintain the yield and the quality of tomatoes and cucumbers while reducing nitrogenous gas emissions.In summary,controlled release fertilizers,the addition of urease inhibitors,and the reduction of application rate of fertilizers are feasible technologies which can reduce N₂O,NH₃ and NO_Xemissions,ensure yield and quality of tomato and cucumber.This study could provide technical support for the sustainable development of tomato and cucumber production.