查看更多>>摘要：Agriculture has a close relationship with nature,but it can also be the source of negative and permanent environmental effects.The use of pesticides in modern agriculture is a common practice,but their side effects on the environment cannot be disregarded.In this study,we evaluated a combination of solarization and ozonation techniques for the elimination of six amide pesticides(boscalid,chlorantraniliprole,cyflufenamid,fluopyram,napropamide,and propyzamide)in soil.Initial experiments were performed with four different soils to assess the efficiency of this methodology at different soil temperatures and ozone dosages under laboratory conditions,and then a greenhouse pot experiment was conducted under controlled conditions during summer.Fifty days after the onset of the experiments,higher degradation percentages of amide pesticides were observed in ozonized soils than in other treated soils,particularly when ozone was applied at 10 cm soil depth.The results show that the utilization of ozonation,along with solarization,represents a valid method for degrading residues of the studied pesticides and suggest that this combined technology may be a promising tool for remediating pesticide-polluted soils.
查看更多>>摘要：Vegetable soils with high nitrogen input are major sources of nitrous oxide(N2O)and nitric oxide(NO),and incorporation of the nitrification inhibitor 3,4-dimethylpyrazole phosphate(DMPP)into soils has been documented to effectively reduce emissions.However,the efficiency of DMPP in terms of soil N2O and NO mitigations varies greatly depending on soil temperature and moisture levels.Thus,further evaluations of DMPP efficiency in diverse environments are required to encourage widespread application.A laboratory incubation study(28 d)was established to investigate the interactive effects of DMPP,temperature(15,25,and 35 ℃),and soil moisture(55％and 80％of water-holding capacity(WHC))on net nitrification rate,N2O and NO productions,and gene abundances of nitrifiers and denitrifiers in an intensive vegetable soil.Results showed that incubating soil with 1％DMPP led to partial inhibition of the net nitrification rate and N2O and NO productions,and the reduction percentage of N2O production was higher than that of NO production(69.3％vs.38.2％)regardless of temperature and soil moisture conditions.The increased temperatures promoted the net nitrification rate but decreased soil N2O and NO productions.Soil moisture influenced NO production more than N2O production,decreasing with the increased moisture level(80％).The inhibitory effect of DMPP on cumulative N2O and NO productions decreased with increased temperatures at 55％WHC.Conversely,the inhibitory effect of DMPP on cumulative N2O production increased with increased temperatures at 80％WHC.Based on the correlation analyses and automatic linear modeling,the mitigation of both N2O and NO productions from the soil induced by DMPP was attributed to the decreases in ammonia-oxidizing bacteria(AOB)amoA gene abundance and NO2-N concentration.Overall,our study indicated that DMPP reduced both N2O and NO productions by regulating the associated AOB amoA gene abundance and NO2-N concentration.These findings improve our insights regarding the implications of DMPP for N2O and NO mitigations in vegetable soils under various climate scenarios.
查看更多>>摘要：Soil ecosystem is experiencing stresses due to climate change,and soil inhabitants try to demonstrate their inherent resistance and resilience against those stresses.Application of nanomaterials as agricultural inputs could bring shifts in resistance and resilience patterns of soil microbes and associated enzymes,especially under short-term heat stress.With this background,the impacts of multi-walled carbon nanotube(MWCNT)on the resistance and resilience of soil biological indicators were evaluated.An incubation experiment was conducted with varied MWCNT concentrations(0,50,100,250,and 500 mg kg-1 soil)for 90 d after 24-h heat stress at 48±2 ℃ to assess the impacts of MWCNT on soil enzyme activities and microbial populations vis-à-vis their resistance and resilience indices under short-term exposure to heat stress.Enzyme activities were reduced after exposure to heat stress.Resistance indices of enzyme activities were enhanced by MWCNT application on day 1 after heat stress,whereas there was no recovery of enzyme activities after 90-d incubation.Like soil enzyme activities,resistance index values of soil microbial populations followed the similar trend and were improved by MWCNT application.Multi-walled carbon nanotube has the potential to improve resistance indices of soil enzyme activities and microbial populations under heat stress,although they could not recover to their original state during periodical incubation after heat stress.This study helps to understand the relative changes of biological indicators under MWCNT and their ability to withstand heat stress.
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