The aim of this experiment was to determine the impacts of climate change on soil profile concentrations and diffusion effluxes of methane in a rice-wheat annual rotation ecosystem in Southeastern China. We initiated ...The aim of this experiment was to determine the impacts of climate change on soil profile concentrations and diffusion effluxes of methane in a rice-wheat annual rotation ecosystem in Southeastern China. We initiated a field experiment with four treatments：ambient conditions（CKs）, CO2 concentration elevated to - 500 μmol/mol（FACE）,temperature elevated by ca. 2°C（T） and combined elevation of CO2 concentration and temperature（FACE ＋ T）. A multilevel sampling probe was designed to collect the soil gas at four different depths, namely, 7 cm, 15 cm, 30 cm and 50 cm. Methane concentrations were higher during the rice season and decreased with depth, while lower during the wheat season and increased with depth. Compared to CK, mean methane concentration was increased by 42%, 57% and 71% under the FACE, FACE ＋ T and T treatments, respectively, at the 7 cm depth during the rice season（p 〈 0.05）. Mean methane diffusion effluxes to the 7 cm depth were positive in the rice season and negative in the wheat season, resulting in the paddy field being a source and weak sink, respectively. Moreover, mean methane diffusion effluxes in the rice season were 0.94, 1.19 and 1.42 mg C/（m^2·hr） in the FACE,FACE ＋ T and T treatments, respectively, being clearly higher than that in the CK. The results indicated that elevated atmospheric CO2 concentration and temperature could significantly increase soil profile methane concentrations and their effluxes from a rice-wheat field annual rotation ecosystem（p 〈 0.05）.展开更多
Vegetable soils with high nitrogen input are major sources of nitrous oxide(N_(2)O)and nitric oxide(NO),and incorporation of the nitrification inhibitor 3,4-dimethylpyrazole phosphate(DMPP)into soils has been document...Vegetable soils with high nitrogen input are major sources of nitrous oxide(N_(2)O)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 N_(2)O 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?C),and soil moisture(55% and 80% of water-holding capacity(WHC))on net nitrification rate,N_(2)O 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 N_(2)O and NO productions,and the reduction percentage of N_(2)O 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 N_(2)O and NO productions.Soil moisture influenced NO production more than N_(2)O production,decreasing with the increased moisture level(80%).The inhibitory effect of DMPP on cumulative N_(2)O and NO productions decreased with increased temperatures at 55%WHC.Conversely,the inhibitory effect of DMPP on cumulative N_(2)O production increased with increased temperatures at 80%WHC.Based on the correlation analyses and automatic linear modeling,the mitigation of both N_(2)O and NO productions from the soil induced by DMPP was attributed to the decreases in ammonia-oxidizing bacteria(AOB)amoA gene abundance and NO_(2)^(-)-N concentration.Overall,our study indicated that DMPP reduced both N_(2)O and NO productions by regulating the associated AOB amoA gene abundance and NO_(2)^(-)-N concentration.These findings improve our insights regarding the implications of DMPP for N_(2)O and NO mitigations in vegetable soils under various climate scenarios.展开更多
Rice-based cropping systems are prevalent in Asia,accounting for 16%of global nitrogen(N)fertilizer consumption and providing billions of calories[1].Among these,the rice-wheat cropping system(RWCS)stands out as a cri...Rice-based cropping systems are prevalent in Asia,accounting for 16%of global nitrogen(N)fertilizer consumption and providing billions of calories[1].Among these,the rice-wheat cropping system(RWCS)stands out as a critical contributor to global food security,covering an extensive area of 23.5 million hectares(mha)in Asia and sustaining 4.4 billion people[2].展开更多
Biochar amendment and substituting chemical fertilizers with organic manure(organic substitution)have been widely reported to increase crop production and decrease reactive nitrogen(Nr)loss including nitrous oxide(N_(...Biochar amendment and substituting chemical fertilizers with organic manure(organic substitution)have been widely reported to increase crop production and decrease reactive nitrogen(Nr)loss including nitrous oxide(N_(2)O),nitric oxide(NO),and ammonia(NH3)emissions,and N runoff and leaching.However,few comprehensive evalua-tions have been performed on the environmental and economic aspects of biochar amendment or organic sub-stitution.Here,we studied the comprehensive effects of biochar amendment,organic substitution,and biochar amendment combined with organic substitution on crop production,Nr loss,and net ecosystem economic benefit(NEEB)in intensive vegetable production by integrating life-cycle assessment for Nr footprints,empirical models for NH3 volatilization and N runoff and leaching derived from peer-reviewed publications and validated by the current measurements and direct field measurement for N_(2)O and NO emissions during 5 consecutive years of vegetable crop rotations.Five fertilization treatments were applied(SN:synthetic fertilizer application;SNB:SN plus 20 t ha^(−1)biochar amendment;SNM:substituting 50%of chemical N fertilizer with organic manure;SNMB:SNM plus 20 t ha^(−1)biochar amendment;and CK:no fertilizer or biochar addition).Compared with the SN,the SNB increased vegetable yield(28.4%,p<0.05;interannually varying from−10 to 74.9%)and nitrogen use efficiency(29.2%,interannually varying from−39.7 to 150.4%),and decreased field Nr loss(45.4%,p<0.01;interannually varying from−40.3 to 78.4%),and thus improved NEEB by 7.1%;meanwhile,the SNM increased vegetable yield(11.6%,interannually varying from−5.4 to 27.1%)and nitrogen use efficiency(45.7%,p<0.05;interannually varying from 2.3 to 154%),reduced field Nr loss(34.9%,p<0.01;interannually varying from 8.4-39.0%),and thus improved NEEB by 17.8%(p<0.05)compared to the SN,being 56.0×10^(3)Chinese Yuan(CNY)ha^(−1)crop^(−1).Due to the high foreground Nr loss during organic manure production and high input costs of biochar production,the SNMB decreased the NEEB by 8.0%as compared to the SN.Moreover,the SNB and SNM improved vegetable qualities by increasing protein,soluble sugar,and vitamin C contents while decreasing nitrate content(p<0.05).Therefore,single application of biochar amendment or organic substitution would achieve better NEEB and product quality in vegetable production.展开更多
基金supported by and the Fundamental Research Funds for the National Science Foundation of China (No. 41171238)the Ministry of Science and Technology (No. 2013BAD11B01)+1 种基金the Central Universities (No. KYTZ201404)the Nonprofit Research Foundation for Agriculture (No. 200903003)
文摘The aim of this experiment was to determine the impacts of climate change on soil profile concentrations and diffusion effluxes of methane in a rice-wheat annual rotation ecosystem in Southeastern China. We initiated a field experiment with four treatments：ambient conditions（CKs）, CO2 concentration elevated to - 500 μmol/mol（FACE）,temperature elevated by ca. 2°C（T） and combined elevation of CO2 concentration and temperature（FACE ＋ T）. A multilevel sampling probe was designed to collect the soil gas at four different depths, namely, 7 cm, 15 cm, 30 cm and 50 cm. Methane concentrations were higher during the rice season and decreased with depth, while lower during the wheat season and increased with depth. Compared to CK, mean methane concentration was increased by 42%, 57% and 71% under the FACE, FACE ＋ T and T treatments, respectively, at the 7 cm depth during the rice season（p 〈 0.05）. Mean methane diffusion effluxes to the 7 cm depth were positive in the rice season and negative in the wheat season, resulting in the paddy field being a source and weak sink, respectively. Moreover, mean methane diffusion effluxes in the rice season were 0.94, 1.19 and 1.42 mg C/（m^2·hr） in the FACE,FACE ＋ T and T treatments, respectively, being clearly higher than that in the CK. The results indicated that elevated atmospheric CO2 concentration and temperature could significantly increase soil profile methane concentrations and their effluxes from a rice-wheat field annual rotation ecosystem（p 〈 0.05）.
基金supported by Jiangsu Province Special Project for Carbon Peak&Carbon Neutral Science and Technology Innovation,China(No.BE2022309)the National Natural Science Foundation of China(Nos.41977078 and 42377292)the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(No.KYCX20_0591)。
文摘Vegetable soils with high nitrogen input are major sources of nitrous oxide(N_(2)O)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 N_(2)O 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?C),and soil moisture(55% and 80% of water-holding capacity(WHC))on net nitrification rate,N_(2)O 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 N_(2)O and NO productions,and the reduction percentage of N_(2)O 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 N_(2)O and NO productions.Soil moisture influenced NO production more than N_(2)O production,decreasing with the increased moisture level(80%).The inhibitory effect of DMPP on cumulative N_(2)O and NO productions decreased with increased temperatures at 55%WHC.Conversely,the inhibitory effect of DMPP on cumulative N_(2)O production increased with increased temperatures at 80%WHC.Based on the correlation analyses and automatic linear modeling,the mitigation of both N_(2)O and NO productions from the soil induced by DMPP was attributed to the decreases in ammonia-oxidizing bacteria(AOB)amoA gene abundance and NO_(2)^(-)-N concentration.Overall,our study indicated that DMPP reduced both N_(2)O and NO productions by regulating the associated AOB amoA gene abundance and NO_(2)^(-)-N concentration.These findings improve our insights regarding the implications of DMPP for N_(2)O and NO mitigations in vegetable soils under various climate scenarios.
基金supported by the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Y201956)the National Key Research and Development Program of China(2017YFD0200104)the National Natural Science Foundation of China(30390080)。
文摘Rice-based cropping systems are prevalent in Asia,accounting for 16%of global nitrogen(N)fertilizer consumption and providing billions of calories[1].Among these,the rice-wheat cropping system(RWCS)stands out as a critical contributor to global food security,covering an extensive area of 23.5 million hectares(mha)in Asia and sustaining 4.4 billion people[2].
基金the National Natural Science Foundation of China(41977078,32001213)the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(KYCX21_0618,KYCX20_0591).
文摘Biochar amendment and substituting chemical fertilizers with organic manure(organic substitution)have been widely reported to increase crop production and decrease reactive nitrogen(Nr)loss including nitrous oxide(N_(2)O),nitric oxide(NO),and ammonia(NH3)emissions,and N runoff and leaching.However,few comprehensive evalua-tions have been performed on the environmental and economic aspects of biochar amendment or organic sub-stitution.Here,we studied the comprehensive effects of biochar amendment,organic substitution,and biochar amendment combined with organic substitution on crop production,Nr loss,and net ecosystem economic benefit(NEEB)in intensive vegetable production by integrating life-cycle assessment for Nr footprints,empirical models for NH3 volatilization and N runoff and leaching derived from peer-reviewed publications and validated by the current measurements and direct field measurement for N_(2)O and NO emissions during 5 consecutive years of vegetable crop rotations.Five fertilization treatments were applied(SN:synthetic fertilizer application;SNB:SN plus 20 t ha^(−1)biochar amendment;SNM:substituting 50%of chemical N fertilizer with organic manure;SNMB:SNM plus 20 t ha^(−1)biochar amendment;and CK:no fertilizer or biochar addition).Compared with the SN,the SNB increased vegetable yield(28.4%,p<0.05;interannually varying from−10 to 74.9%)and nitrogen use efficiency(29.2%,interannually varying from−39.7 to 150.4%),and decreased field Nr loss(45.4%,p<0.01;interannually varying from−40.3 to 78.4%),and thus improved NEEB by 7.1%;meanwhile,the SNM increased vegetable yield(11.6%,interannually varying from−5.4 to 27.1%)and nitrogen use efficiency(45.7%,p<0.05;interannually varying from 2.3 to 154%),reduced field Nr loss(34.9%,p<0.01;interannually varying from 8.4-39.0%),and thus improved NEEB by 17.8%(p<0.05)compared to the SN,being 56.0×10^(3)Chinese Yuan(CNY)ha^(−1)crop^(−1).Due to the high foreground Nr loss during organic manure production and high input costs of biochar production,the SNMB decreased the NEEB by 8.0%as compared to the SN.Moreover,the SNB and SNM improved vegetable qualities by increasing protein,soluble sugar,and vitamin C contents while decreasing nitrate content(p<0.05).Therefore,single application of biochar amendment or organic substitution would achieve better NEEB and product quality in vegetable production.
