Effects Of Biochar And Plastic Film Mulching On CH₄ And CO₂ Emissions From Vegetable Fields

Plastic film mulching technology is an important agricultural production management measure,and biochar,as a hot material in recent years,has been favored by scholars in various fields for its unique properties.The application of biochar and plastic film mulching technology have many advantages,such as promoting crop growth,soil modification,increasing yield,etc.However,there are few studies on the impact of the two technologies on the emission of greenhouse gases such as CH₄ and CO₂.Therefore,in this paper,the radish-pepper wheel was taken as the research object,and the in-situ monitoring of vegetable fields was carried out for one year(from October 2019 to December 2020).The experiments were carried out with the addition of three kinds of biochars of 0t·hm^-2,20t·hm^-2 and40t·hm^-2 under the film-covered and conventional treatments(the film-covered treatments were marked as FC₀,FC₂₀ and FC₄₀ respectively)Conventional treatments are marked as NFC₀,NFC₂₀,NFC₄₀ respectively,with a total of 6treatments.In addition,this paper also explores the effects of biochar aging on greenhouse gas emissions and soil physical and chemical properties.From September,2020 to December,2020,the aging process of biochar was simulated by blue light bottle indoor culture experiment.Among them,50t hm^-2 fresh biochar,50t·hm^-2 aged biochar,100 t·hm^-2 fresh biochar and 100t·hm^-2 aged biochar were applied to study their effects on soil respiration,which provided a scientific basis for the application of biochar to reduce greenhouse gas emission in soil.1.Effects of biochar and plastic film mulching on soil hydrothermal conditions in vegetable fieldsIn the radish-pepper planting cycle,the soil temperature in 10cm,20cm and30cm underground under plastic film mulching treatment was higher than that under conventional treatment,and the soil temperature in 10cm 20cm and 30cm underground increased by 5.3%,7.3%and 7.1%respectively on average.During the observation period,there was no significant difference in soil moisture content between biochar and plastic film mulching(P>0.05),and the interaction effect between biochar and plastic film mulching had no significant effect on soil moisture content(P>0.05),but the soil moisture content under plastic film mulching was higher than that under conventional treatment.2.Effects of biochar and plastic film mulching on CH₄emission from vegetable fields1)during radish-pepper planting,The cumulative CH₄emissions during the observation period are-2.07±0.71,-2.91±1.26,0.31±2.97,1.88±0.41,-6.42±6.53,0.31±0.83kg·ha^-1,respectively.There is no significant difference in CH₄ cumulative emissions between biochar and plastic film treatment(P>0.05),and there is no significant difference in CH₄ cumulative emissions between them(P>0.05).2)The CH₄ fluxes of FC₄₀,FC₂₀,FC₀,NFC₄₀,NFC₂₀ and NFC₀ had no significant correlation with surface temperature,5cm underground temperature and soil moisture content(P>0.05).3.Effects of biochar and plastic film mulching on CH₄ and CO₂ concentrations in vegetable fields1)during radish-pepper planting,the effects of biochar and plastic film mulching on CH₄ profile concentration in vegetable fields reached a very significant level(P<0.01),and the interaction between biochar and plastic film mulching reached a very significant level(P<0.01),and CH₄ concentration decreased with the increase of depth.2)During radish-pepper planting,there was a significant difference in CO₂concentration between biochar application and plastic film mulching(P<0.01).There is also a significant difference(P<0.01)in the cross-sectional CO₂concentration.With the increase of depth,the CO₂ concentration in the cross-sectional CO₂ concentration increases continuously4.Effects of biochar and plastic film mulching on respiration rate of vegetable ecosystemDuring radish-pepper planting,respectively.There is no significant difference in ecosystem respiration rate between radish season and pepper season(P>0.05),and the interaction effect between biochar and plastic film mulching has no significant effect on ecosystem respiration rate(P>0.05).In radish season and pepper season,there was a significant positive correlation between ecosystem respiration rate and surface and underground temperature(P<0.01),but no significant correlation with water content and soil organic carbon content.5.Effects of biochar and plastic film mulching on CO₂ net exchange fluxIn the radish-pepper planting period,respectively.There is basically no significant difference in respiration rate between radish season and pepper season(P>0.05),but the application of biochar does not significantly improve the net exchange flux,and the interaction effect between biochar and plastic film treatment has no significant effect on the net exchange flux of CO₂(P>0.05)7.Effects of biochar and plastic film mulching on crop yieldDuring the whole planting season,the interaction between biochar application and film mulching treatment had no significant effect on crop yield,but film mulching treatment increased crop yield,and biochar application of 20t·hm^-2 could increase yield,but biochar application of 40t·hm^-2 had no obvious effect on yield increase,and even decreased yield.8.Study on soil respiration and organic carbon content of aged and fresh biocharDuring the indoor culture experiment,the CO₂ emission fluxes of blank,fresh50t·hm^-2,fresh 100t·hm^-2,aged 50t·hm^-2 and aged 100 t·hm^-2 were 140.26±103.31,158.30±115.45,208.88±121.92,165.18±161.19,150.00±141.82 mg·kg^-1·h^-1,respectively.The accumulative emission of CO₂ is fresh 100t·hm^-2(355.50±56.67g kg^-1)>fresh 50t·hm^-2(290.25±2.94g·kg^-1)>aged 50t·hm^-2(295.65±51.94g·kg^-1)...