| Ammonia is an alkaline gas in the atmosphere.Ammonium sulfate and ammonium nitrate formed by reaction with acid gas in the atmosphere are important components of PM2.5.Agricultural production is the main source of ammonia in the atmosphere,and ammonia emitted by the plantation industry accounts for about 50%of the emissions from agricultural sources.Excessive fertilization is the main reason for increased ammonia volatilization in the planting industry and is common in facility vegetables.Excessive fertilization not only increases the volatilization of ammonia in the soil,but also seriously affects the yield and quality of facility vegetables.In this paper,the conventional fertilization schemes for tomato production in solar greenhouse in autumn and winter were used as contrast.By setting different fertilization reduction schemes,the effects of different fertilization schemes on soil physicochemical properties,ammonia volatilization,tomato yield,quality and the output-input were studied.The key factors affecting the soil ammonia volatilization were analyzed.The results are as follows:1.The pH value generally shows a downward trend throughout the fertilization cycle,and decreases with the decrease in the amount of fertilization.Adding organic fertilizer(chicken manure)can increase the soil pH value.The EC value showed an overall upward trend throughout the fertilization cycle,and decreased with the decrease in the amount of fertilization.The application of organic fertilizer(chicken maure)can increase the soil EC value.The organic matter content showed a general downward trend throughout the fertilization cycle.The reduced application of chemical fertilizers will not affect the changes in the organic matter content.The increased application of organic fertilizer can increase the organic matter content.The concentration of ammonium nitrogen showed a downward trend in the whole fertilization cycle,and it decreased with the decrease of the amount of fertilization.The application of organic fertilizer can reduce the concentration of ammonium nitrogen in the soil.The concentration of nitrate nitrogen showed an overall upward trend throughout the fertilization cycle,and decreased with the decrease of the amount of fertilization.The application of organic fertilizer can increase the concentration of nitrate nitrogen in the soil.2.The rate of ammonia volatilization was the highest on the first day after fertilization for the base fertilizer and top dressing.After basic fertilizer,compared with CK(local conventional dosage),The ammonia volatilization rates of C1(organic fertilizer constant+chemical fertilizer 10%reduction),C2(organic fertilizer constant+chemical fertilizer 20%reduction),C3(organic fertilizer increase 30%+chemical fertilizer reduction 10%),C4(organic fertilizer 30%increase+chemical fertilizer Reduced by 20%)and C5(increased organic fertilizer by 30%+reduced chemical fertilizer by 30%)respectively decreased by 11.15%,23.06%,24.90%,32.25%and 36.67%.After 1-5 top dressing,compared with CK,the ammonia volatilization rates of C1,C2,C3,C4 and C5 respectively decreased by 7.92%-21.68%,14.14%-30.86%,11.97%-22.43%,15.83-32.99%and 21.75-39.26%.The cumulative amount of ammonia volatiles in the whole growth period was 8.89kg·hm-2,which was the highest.Compared with CK,the ammonia volatilization accumulation of C1,C2,C3,C4 and C5 respectively decreased by 14.53%-30.55%.3.Taking ammonia volatilization rate as the dependent variable Y,taking pH value,organic matter content,EC value,nitrate nitrogen concentration,ammonium nitrogen concentration,urease activity,daily average soil temperature,daily average soil humidity,daily average air temperature,daily average air humidity is the independent variables X1,X2,X3,X4,X5,X6,X7,X8,X9,X10,The correlation analysis between soil and environmental factors and ammonia volatilization rate showed that soil ammonium nitrogen concentration,urease activity,soil daily average temperature and air daily average temperature were extremely significantly positively correlated with ammonia volatilization rate,while nitrate nitrogen concentration were significantly positively correlated with ammonia volatilization rate.The soil daily average humidity is significantly negatively correlated with ammonia volatilization rate.Path analysis showed that ammonium nitrogen concentration,soil daily average temperature and air daily average temperature directly affected the ammonia volatilization rate,nitrate nitrogen concentration and soil daily average humidity indirectly affected the ammonia volatilization rate.The regression model is obtained by stepwise regression analysis:Y=-1.6677+0.061 1X4+0.0375X5+0.0027X7-0.0010X8+0.0084X9.Comprehensive correlation analysis,path analysis and stepwise regression analysis showed that ammonium nitrogen concentration,soil nitrate nitrogen concentration,daily average soil temperature,daily average soil humidity and daily average air temperature were the main factors affecting soil ammonia volatilization in solar greenhouse.4.Compared with the local conventional fertilization scheme,plant height of C1 and C3 tomatoes increased by 36.72%and 32.40%,stem diameter of C3 increased by 10.02%,leaf number of C1-C5 increased by 3.27%-16.99%,incidence rate decreased by 22.95%-64.01%,yield increased by 8.57%-22.56%,soluble solids increased by 5.52%-18.31%,soluble sugars increased by 2.38%-40.47%,and vitamin C content increased by 6.63-51.28%,respectively.5.Under the experimental conditions,compared with the local conventional fertilization program,C2(organic fertilizer constant+chemical fertilizer 20%reduction)ammonia volatilization decreased by 22.04%,tomato yield increased by 22.56%,soluble solid content increased by 11.34%,and fertilization cost decreased 10.27%,sales revenue increased by 22.56%,output-to-input ratio increased by 36.61%;C5(increased organic fertilizer by 30%+ reduced chemical fertilizer by 30%)ammonia volatilization decreased by 30.55%,tomato production increased by 12.28%,and soluble solid content increased by 18.31 respectively%,the soluble sugar content increased by 18.31%,the cost of fertilization was reduced by 1.87%,the sales revenue increased by 12.28%,and the ratio of production to investment increased by 14.45%.It can be seen that under the premise of increasing tomato production,quality and efficiency,through optimizing the fertilization plan,the ammonia reduction potential can reach more than 30%. |
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