The effect of application of pig manure (PM) on the structural characteristics of humic acids (HAs) of brown soil was studied in field and incubation experiments. The results showed that the number-average molecular w...The effect of application of pig manure (PM) on the structural characteristics of humic acids (HAs) of brown soil was studied in field and incubation experiments. The results showed that the number-average molecular weights (Mn), the ratios of C/ H, C/ N and O/C, the contents of carboxyl and phenolic hydroxyl groups, the content ofaromatic C, the values of E2, E4and λ Exmax of HAs all decreased; whereas, the contents of alkyl C and O-alkyl C, the ratio of carboxyl to phenolic hydroxyl groups, the degree of oxidation stability, the absorption intensity at 285 mμ (UV), and 2920cm-1 of HAs increased after the application of PM. The above results indicated that the molecular structure of HAs tended to be more aliphatic and simpler after the application of PM.展开更多
ARB was investigated in different soil types following manure application.CTC-manure induced more resistance of soil indigenous microbes in fluvo-aquic soil.Lactobacillus,Dyella,Ralstonia,and Bacillus were the key dif...ARB was investigated in different soil types following manure application.CTC-manure induced more resistance of soil indigenous microbes in fluvo-aquic soil.Lactobacillus,Dyella,Ralstonia,and Bacillus were the key different genera.Manure control is an effective way to reduce the risk of soil ARB.展开更多
Microbial attributes were compared between soil fauna gut and plant rhizosphere.•Manure applications decreased or increased gut or rhizosphere bacterial diversity.•Stochastic or deterministic processes drove gut or rh...Microbial attributes were compared between soil fauna gut and plant rhizosphere.•Manure applications decreased or increased gut or rhizosphere bacterial diversity.•Stochastic or deterministic processes drove gut or rhizosphere bacterial assembly.•Manure applications increased bacterial network complexity of gut and rhizosphere.Diverse microbes inhabit animals and plants,helping their hosts perform multiple functions in agricultural ecosystems.However,the responses of soil fauna gut and plant rhizosphere microbiomes to livestock manure applications are still not well understood.Here we fed Protaetia brevitarsis larvae(PBL)with chicken manure and collected their frass.The frass and manure were applied as fertilizers to lettuce pots.We then compared the changes of microbial diversity,community assembly,and potential functions between the gut group(i.e.,all PBL gut and frass samples)and the rhizosphere group(i.e.,all rhizosphere soil samples).We revealed that manure applications(i.e.,feeding or fertilization)decreased bacterial diversity in the gut group but increased that in the rhizosphere group.Particularly,the proportions of Bacilli in the gut group and Gammaproteobacteria in the rhizosphere group were increased(up to a maximum of 33.8%and 20.4%,respectively)after manure applications.Stochastic and deterministic processes dominated community assembly in the gut and rhizosphere microbiomes,respectively.Manure applications increased the microbial co-occurrence network complexity of both the gut and rhizosphere groups.Moreover,the proportions of functional taxa associated with human/animal pathogens in the gut group and carbon/nitrogen cycling in the rhizosphere group were enhanced(up to 2.6-fold and 24.6-fold,respectively).Our findings illustrate the different responses of microbial diversity,community assembly,and potential functions in soil fauna gut and plant rhizosphere to manure applications.The results could enhance our knowledge on the reasonable utilization of animal and plant microbiomes in agricultural management.展开更多
To understand the long-term effects of combined organic and chemical nitrogen fertilization on soil organic C(SOC) and total N(TN), we conducted a 30-year field experiment with a wheat–maize rotation system on the Hu...To understand the long-term effects of combined organic and chemical nitrogen fertilization on soil organic C(SOC) and total N(TN), we conducted a 30-year field experiment with a wheat–maize rotation system on the Huang-HuaiHai Plain during 1990–2019. The experimental treatments consisted of five fertilizer regimes: no fertilizer(control), chemical fertilizer only(NPK), chemical fertilizer with straw(NPKS), chemical fertilizer with manure(NPKM), and 1.5 times the rate of NPKM(1.5NPKM). The NPK, NPKS, and NPKM treatments had equal N inputs. The crop yields were measured over the whole experimental duration. Soil samples were collected from the topsoil(0–10 and 10–20 cm) and subsoil(20–40 cm) layers for assessing soil aggregates and taking SOC and TN measurements. Compared with the NPK treatment, the SOC and TN contents increased significantly in both the topsoil(24.1–44.4% for SOC and 22.8–47.7% for TN) and subsoil layers(22.0–47.9% for SOC and 19.8–41.8% for TN) for the organically amended treatments(NPKS, NPKM and 1.5NPKM) after 30 years, while no significant differences were found for the average annual crop yields over the 30 years of the experiment. The 0–10 cm layer of the NPKS treatment and the 20–40 cm layer of the NPKM treatment had significantly higher macroaggregate fraction mass proportions(19.8 and 27.0%) than the NPK treatment. However, the 0–10 and 20–40 cm layers of the 1.5NPKM treatment had significantly lower macroaggregate fraction mass proportions(–19.2 and –29.1%) than the control. The analysis showed that the higher SOC and TN in the soil of organically amended treatments compared to the NPK treatment were related to the increases in SOC and TN protected in the stable fractions(i.e., free microaggregates and microaggregates within macroaggregates), in which the contributions of the stable fractions were 81.1–91.7% of the increase in SOC and 83.3–94.0% of the increase in TN, respectively. The relationships between average C inputs and both stable SOC and TN stocks were significantly positive with R2 values of 0.74 and 0.72(P<0.01) for the whole 40 cm soil profile, which indicates the importance of N for soil C storage. The results of our study provide key evidence that long-term combined organic and chemical nitrogen fertilization, while maintaining reasonable total N inputs, benefited soil C and N storage in both the topsoil and subsoil layers.展开更多
Soil in greenhouses is likely to suffer a gradual decline in aggregate stability. Determination of the effects of different fertiliser practices on soil aggregate stability is important for taking advantage of solar g...Soil in greenhouses is likely to suffer a gradual decline in aggregate stability. Determination of the effects of different fertiliser practices on soil aggregate stability is important for taking advantage of solar greenhouses. Soil aggregate stability and iron （Fe） and aluminium （A1） oxide contents were investigated in a 26-year long-term fertilisation experiment in greenhouse in Shenyang, China, under eight fertiliser treatments： manure （M）, fertiliser N （FN）, fertiliser N with manure （MN）, fertiliser P （FP）, fertiliser P with manure （MP）, fertiliser NP （FNP）, fertiliser NP with manure （MNP）, and control without any fertiliser （CK）. A wet sieving method was used to determine aggregate size distribution and water-stable aggregates （WSA）, mean weight diameter and geometric mean diameter as the indices of soil aggregate stability. Different fertiliser treatments had a statistically significant influence on aggregate stability and Fe and A1 oxide contents. Long-term application of inorganic fertilisers had no obvious effects on the mass proportion of aggregates. By contrast, manure application significantly increased the mass proportion of macroaggregates at the expense of microaggregates. All treatments, with the exception of FNP, significantly increased the stability of macroaggregates but decreased that of microaggregates when compared with CK. Aggregation under MP and MN was better than that under M and MNP; however, no significant differences were found among inorganic fertiliser treatments （i.e., FN, FP, and FNP）. A positive relation was found between pyrophosphate-extractable Fe and WSA （r=0.269）, but no significant relations were observed between other Fe and Al oxides and aggregate stability.展开更多
Study on soil phosphorus（P） fraction is an important aspect in probing the mechanisms of soil P accumulation in farmland and mitigating its losing risk to the environment. We used a sequential extraction method to e...Study on soil phosphorus（P） fraction is an important aspect in probing the mechanisms of soil P accumulation in farmland and mitigating its losing risk to the environment. We used a sequential extraction method to evaluate the impacts of long-term fertilization and straw incorporation on inorganic, organic, and residual P（Pi, Po, and Pre） fractions in the plow layer（0–20 cm） of acidic paddy soil in southern China. The experiment comprised of six treatments：（i） no fertilizer control（CK）;（ii） straw incorporation and green manure（SG）;（iii） nitrogen and P fertilizer（NP）;（iv） NP＋SG;（v） NP＋K fertilizer（NPK）; and（vi） NPK＋SG. The results showed that, compared to the initial total soil P content（TSP, 600 mg kg^–1 in 1990）, long-term（20 years） combined continuous P fertilizer and SG significantly increased P accumulation（by 13–20%） while single fertilization（39.3 kg P ha^–1 yr^–1） could maintain soil P status at the most. The average soil P fractions comprised of extractable Pi, Po, and Pre by 51.7, 33.4, and 14.9% in total soil P, respectively. With comparison of no fertilizer addition（CK）, long-term single fertilization significantly（P〈0.05） increased the accumulation of Na HCO3^–, Na OH^–, and HCl^– extractable Pi fractions accounting for two- to three-fold, while SG increased the accumulation of Na HCO3^– and Na OH^– extractable Piand Po accounting for 12–60%. Though the mobilization of Pre fractions was not significant（P〉0.05）, our data indicate that SG may partially substitute for fertilizer P input and minimizing soil P accumulation and subsequent environmental risk in the subtropical paddy soil.展开更多
Biological nitrogen(N)fixation(BNF)driven by diazotrophs is an important pathway for N input in agricultural ecosystems.However,free-living BNF and its associated diazotrophic communities under different fertilization...Biological nitrogen(N)fixation(BNF)driven by diazotrophs is an important pathway for N input in agricultural ecosystems.However,free-living BNF and its associated diazotrophic communities under different fertilization practices in acidic soils are poorly studied.Here,we conducted a long-term(29 years)fertilization experiment to explore how fertilization affected free-living BNF via changing biotic and abiotic variables.The fertilization treatments included an unfertilized control(CK),chemical N,phosphorus(P),and potassium(K)fertilizers(NPK),NPK plus lime(NPKL),NPK plus straw(NPKS),NPK plus straw and lime(NPKSL),and NPK plus manure(NPKM).Compared with CK(1.51 nmol C_(2)H_(2)g^(-1)d^(-1)),BNF rate was significantly(P<0.05)higher in NPKM(1.99 nmol C_(2)H_(2)g^(-1)d^(-1))but lower in NPK(0.55 nmol C_(2)H_(2)g^(-1)d^(-1)),NPKL(0.61 nmol C_(2)H_(2)g^(-1)d^(-1)),and NPKS(0.69nmol C_(2)H_(2)g^(-1)d^(-1)).Similarly,chemical fertilization treatments without manure reduced the gene abundance(0.71×10^(8)-1.18×10^(8)copies g^(-1))andα-diversity(Shannon index,1.11-2.43)of diazotrophic communities,whereas the treatment with manure had a positive effect on diazotrophic abundance(3.23×10^(8)copies g^(-1))and Shannon index(3.36).Non-parametric multivariate analysis of variance(PERMANOVA)suggested that manure application(R^(2)=0.212,P=0.001)had a stronger influence on diazotrophic community composition than the addition of lime(R^(2)=0.115,P=0.019)or straw(R^(2)=0.064,P=0.161).Random forest modeling revealed that BNF rates can be significantly(P<0.05)explained by soil pH(9.9%),diazotrophic community attributes(composition,8.5%;Chao 1 index,8.1%;abundance,6.0%;Shannon index,5.7%),and soil total carbon(5.1%).Partial least squares path modeling(PLS-PM)suggested that the diazotrophic community attributes and soil properties mainly provided direct and indirect contributions to the variations in BNF rates,respectively.The dominant genera,Pelomonas,Azospirillum,and Dechloromonas,were positively associated with BNF rates,with their members being observed as keystone species in the community network.Application of chemical fertilizers combined with manure is an effective practice for improving BNF in acidic soils by affecting soil diazotrophic communities.展开更多
Utilizing straw as feed and applying cattle and sheep manure fertilizer to the field plays an important role in solving the shortage of feed raw material resources,alleviating the conflict between human beings and liv...Utilizing straw as feed and applying cattle and sheep manure fertilizer to the field plays an important role in solving the shortage of feed raw material resources,alleviating the conflict between human beings and livestock,and realizing the full utilization of straw as a resource and green and low-carbon circular development.We carried out an investigation on the feed utilization of crop straw in Sichuan Province,comprehensively grasped the crop straw resources and its utilization as feed in this province,deeply analyzed the existing problems,and put forward countermeasures and suggestions according to the actual situation in Sichuan,which plays an important role in accelerating the process of straw feed utilization,promoting green development,implementing the rural revitalization strategy,and building a beautiful Sichuan.展开更多
Long-term application of chemical fertilizers causes soil degradation and nitrogen(N)loss,but these effects could be alleviated by organic fertilizers.In addition,crop rotation is a feasible practice to increase soil ...Long-term application of chemical fertilizers causes soil degradation and nitrogen(N)loss,but these effects could be alleviated by organic fertilizers.In addition,crop rotation is a feasible practice to increase soil fertility,soil quality and crop yields comparing with monocultural cropping patterns.However,questions remain concerning how the soil microbiome responds to different manure application rates under crop rotations.Here,we collected soil samples from a rice-rape system to investigate the response of the soil microbiome to nine years of pig manure application at different rates(CK:0 kg ha^(-1),M1:1930 kg ha^(-1),M2:3860 kg ha^(-1) and M3:5790 kg ha^(-1)).Our results revealed that the bacterialα-diversity(Chao1 and Shannon index)in the rape season increased first and then decreased with increasing manure application rates,and a high manure load tended to decrease the bacterialα-diversity in the rice season.Long-term manure application enriched some copiotrophic bacteria,such as Proteobacteria and Actinobacteria,while it decreased the relative abundance of Nitrospirae.Redundancy analysis(RDA)and the Mantel test indicated that soil pH,TC,TN,AP,C/P and N/P ratios were the main factors influencing bacterial communities.Moreover,network analysis showed that a low manure application rate shaped a complexly connected and stable bacterial community,while higher manure application rate decreased the stability of the bacterial network.These findings improve our understanding of bacterial responses to longterm manure application under crop rotations and their relationships with soil factors,especially in the context of increasing fertilizer inputs.展开更多
Greenhouse gas emissions （GHGs） from swine production systems are relatively well researched with the exception of emissions from land application of manure. GttGs inventories are needed for process- based modeling ...Greenhouse gas emissions （GHGs） from swine production systems are relatively well researched with the exception of emissions from land application of manure. GttGs inventories are needed for process- based modeling and science-based regulations. Thus, the objective of this observational study was to measure GHG fluxes from land application of swine manure on a typical corn field. Assessment of GHG emissions from deep injected land-applied swine manure, Phil and reapplication in the spring, on a typical US Midwestern corn-on-corn farm was completed. Static chambers were used Ibr flux measurement along with gas analysis on a GC-FID-ECD＋ Measured gas concentrations were used to estimate GHGs flux using four different models： linear regression, nonlinear regression, first order linear regression and the revised Hutchinson and Mosier （HMR） model, respectively for comparisons.Cumulative flux esmnates after manure apphcatmn of 5.85×10 g·ha^-1（1 ha = 0.01 km） of CO2 6.60×10^1g·ha^-1 of CH4 and3.48 ×10^3g·ha^-1 N2O for the fall trial and 3.11×10^6g·ha^-1 of CO2,2.95×10^3g·ha^-1 of OH4, and 1.47×10^4g·ha^-1 N2O after the spnng reapphcation trial were observed. The N2O net cumulative flux represents 0.595% of nitrogen applied in swine manure for the fall trial.展开更多
Organic fertilization may influence soil carbon−iron(C-Fe)cycling and enhance phosphorus(P)availability,yet the direct connection between soil organic matter molecules and iron-reducing processes in long-term fertiliz...Organic fertilization may influence soil carbon−iron(C-Fe)cycling and enhance phosphorus(P)availability,yet the direct connection between soil organic matter molecules and iron-reducing processes in long-term fertilized paddy soils remains underexplored.In this study,we conducted a microcosm experiment using paddy soils treated with six distinct fertilization regimes involving varying P and organic matter inputs up to five years.We assessed P activation under reflooding conditions,evaluated Fe reduction,and characterized dissolved organic matter(DOM)at the molecular level using Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS),alongside profiling soil microbial community composition via high-throughput sequencing.Our findings revealed that after 25 days of reflooding,soil Olsen-P content increased by an average of 73%compared to its initial state,showing a strong correlation with the Fe reduction process.Specifically,treatments involving pig manure application exhibited higher Fe reduction rates and enhanced P activation,highlighting the role of organic matter in facilitating Fe reduction.Examination of Fe-reducing microorganisms revealed that their relative abundance was decoupled from Fe reduction and P release rates,potentially due to limitations of lower soil organic matter content.Further analysis of DOM composition and network structures suggested that high-molecular-weight DOM,particularly lignin,acted as key resources for Fe-reducing microbes,thereby driving Fe reduction and promoting P release.Overall,our study highlights the crucial role of soil DOM in enabling microbial-driven Fe reduction and enhancing P availability,providing insights valuable for sustainable agricultural practices.展开更多
文摘The effect of application of pig manure (PM) on the structural characteristics of humic acids (HAs) of brown soil was studied in field and incubation experiments. The results showed that the number-average molecular weights (Mn), the ratios of C/ H, C/ N and O/C, the contents of carboxyl and phenolic hydroxyl groups, the content ofaromatic C, the values of E2, E4and λ Exmax of HAs all decreased; whereas, the contents of alkyl C and O-alkyl C, the ratio of carboxyl to phenolic hydroxyl groups, the degree of oxidation stability, the absorption intensity at 285 mμ (UV), and 2920cm-1 of HAs increased after the application of PM. The above results indicated that the molecular structure of HAs tended to be more aliphatic and simpler after the application of PM.
基金funded by the Yangtze River Ecological Protection Project(2022-LHYJ-02-0304)the National Key Research and Development Program(2021YFC3201503)+2 种基金the Start-up Funds for Doctoral Research Projects of Jilin Normal University(0420221)the Agricultural Science and Technology Innovation Program of China(CAAS-CFSGLCA-IEDA-202302)the Beijing Innovation Consortium of Livestock Research System(BAICO5-2022).
文摘ARB was investigated in different soil types following manure application.CTC-manure induced more resistance of soil indigenous microbes in fluvo-aquic soil.Lactobacillus,Dyella,Ralstonia,and Bacillus were the key different genera.Manure control is an effective way to reduce the risk of soil ARB.
基金financially supported by the Science and Technology Project of Fujian Province(2022J02026)the National Natural Science Foundation of China(32171642 and 32070511).
文摘Microbial attributes were compared between soil fauna gut and plant rhizosphere.•Manure applications decreased or increased gut or rhizosphere bacterial diversity.•Stochastic or deterministic processes drove gut or rhizosphere bacterial assembly.•Manure applications increased bacterial network complexity of gut and rhizosphere.Diverse microbes inhabit animals and plants,helping their hosts perform multiple functions in agricultural ecosystems.However,the responses of soil fauna gut and plant rhizosphere microbiomes to livestock manure applications are still not well understood.Here we fed Protaetia brevitarsis larvae(PBL)with chicken manure and collected their frass.The frass and manure were applied as fertilizers to lettuce pots.We then compared the changes of microbial diversity,community assembly,and potential functions between the gut group(i.e.,all PBL gut and frass samples)and the rhizosphere group(i.e.,all rhizosphere soil samples).We revealed that manure applications(i.e.,feeding or fertilization)decreased bacterial diversity in the gut group but increased that in the rhizosphere group.Particularly,the proportions of Bacilli in the gut group and Gammaproteobacteria in the rhizosphere group were increased(up to a maximum of 33.8%and 20.4%,respectively)after manure applications.Stochastic and deterministic processes dominated community assembly in the gut and rhizosphere microbiomes,respectively.Manure applications increased the microbial co-occurrence network complexity of both the gut and rhizosphere groups.Moreover,the proportions of functional taxa associated with human/animal pathogens in the gut group and carbon/nitrogen cycling in the rhizosphere group were enhanced(up to 2.6-fold and 24.6-fold,respectively).Our findings illustrate the different responses of microbial diversity,community assembly,and potential functions in soil fauna gut and plant rhizosphere to manure applications.The results could enhance our knowledge on the reasonable utilization of animal and plant microbiomes in agricultural management.
基金supported by the Agricultural Science and Technology Innovation Program (ASTIP) of Chinese Academy of Agricultural Sciences (CAAS-CSAL-202302 and GY2023-12-7)the Fundamental Research Funds for Central Non-Profit Scientific Institutions, China (1610132019014)the National Key Research and Development Program of China (2016YFD0200101 and 2018YFD0200804)。
文摘To understand the long-term effects of combined organic and chemical nitrogen fertilization on soil organic C(SOC) and total N(TN), we conducted a 30-year field experiment with a wheat–maize rotation system on the Huang-HuaiHai Plain during 1990–2019. The experimental treatments consisted of five fertilizer regimes: no fertilizer(control), chemical fertilizer only(NPK), chemical fertilizer with straw(NPKS), chemical fertilizer with manure(NPKM), and 1.5 times the rate of NPKM(1.5NPKM). The NPK, NPKS, and NPKM treatments had equal N inputs. The crop yields were measured over the whole experimental duration. Soil samples were collected from the topsoil(0–10 and 10–20 cm) and subsoil(20–40 cm) layers for assessing soil aggregates and taking SOC and TN measurements. Compared with the NPK treatment, the SOC and TN contents increased significantly in both the topsoil(24.1–44.4% for SOC and 22.8–47.7% for TN) and subsoil layers(22.0–47.9% for SOC and 19.8–41.8% for TN) for the organically amended treatments(NPKS, NPKM and 1.5NPKM) after 30 years, while no significant differences were found for the average annual crop yields over the 30 years of the experiment. The 0–10 cm layer of the NPKS treatment and the 20–40 cm layer of the NPKM treatment had significantly higher macroaggregate fraction mass proportions(19.8 and 27.0%) than the NPK treatment. However, the 0–10 and 20–40 cm layers of the 1.5NPKM treatment had significantly lower macroaggregate fraction mass proportions(–19.2 and –29.1%) than the control. The analysis showed that the higher SOC and TN in the soil of organically amended treatments compared to the NPK treatment were related to the increases in SOC and TN protected in the stable fractions(i.e., free microaggregates and microaggregates within macroaggregates), in which the contributions of the stable fractions were 81.1–91.7% of the increase in SOC and 83.3–94.0% of the increase in TN, respectively. The relationships between average C inputs and both stable SOC and TN stocks were significantly positive with R2 values of 0.74 and 0.72(P<0.01) for the whole 40 cm soil profile, which indicates the importance of N for soil C storage. The results of our study provide key evidence that long-term combined organic and chemical nitrogen fertilization, while maintaining reasonable total N inputs, benefited soil C and N storage in both the topsoil and subsoil layers.
基金supported by the National Natural Science Foundation of China(No.31171997)the Fifth Session of Geping Green Action-123 Project of Liaoning Environmental Research and Education,China(No.CEPF2012-123-1-4)the Innovative Graduate Training Program of Shenyang Agricultural University of China
文摘Soil in greenhouses is likely to suffer a gradual decline in aggregate stability. Determination of the effects of different fertiliser practices on soil aggregate stability is important for taking advantage of solar greenhouses. Soil aggregate stability and iron （Fe） and aluminium （A1） oxide contents were investigated in a 26-year long-term fertilisation experiment in greenhouse in Shenyang, China, under eight fertiliser treatments： manure （M）, fertiliser N （FN）, fertiliser N with manure （MN）, fertiliser P （FP）, fertiliser P with manure （MP）, fertiliser NP （FNP）, fertiliser NP with manure （MNP）, and control without any fertiliser （CK）. A wet sieving method was used to determine aggregate size distribution and water-stable aggregates （WSA）, mean weight diameter and geometric mean diameter as the indices of soil aggregate stability. Different fertiliser treatments had a statistically significant influence on aggregate stability and Fe and A1 oxide contents. Long-term application of inorganic fertilisers had no obvious effects on the mass proportion of aggregates. By contrast, manure application significantly increased the mass proportion of macroaggregates at the expense of microaggregates. All treatments, with the exception of FNP, significantly increased the stability of macroaggregates but decreased that of microaggregates when compared with CK. Aggregation under MP and MN was better than that under M and MNP; however, no significant differences were found among inorganic fertiliser treatments （i.e., FN, FP, and FNP）. A positive relation was found between pyrophosphate-extractable Fe and WSA （r=0.269）, but no significant relations were observed between other Fe and Al oxides and aggregate stability.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences(KZCX2-YW-T07)the National Natural Science Foundation of China (41171396)
文摘Study on soil phosphorus（P） fraction is an important aspect in probing the mechanisms of soil P accumulation in farmland and mitigating its losing risk to the environment. We used a sequential extraction method to evaluate the impacts of long-term fertilization and straw incorporation on inorganic, organic, and residual P（Pi, Po, and Pre） fractions in the plow layer（0–20 cm） of acidic paddy soil in southern China. The experiment comprised of six treatments：（i） no fertilizer control（CK）;（ii） straw incorporation and green manure（SG）;（iii） nitrogen and P fertilizer（NP）;（iv） NP＋SG;（v） NP＋K fertilizer（NPK）; and（vi） NPK＋SG. The results showed that, compared to the initial total soil P content（TSP, 600 mg kg^–1 in 1990）, long-term（20 years） combined continuous P fertilizer and SG significantly increased P accumulation（by 13–20%） while single fertilization（39.3 kg P ha^–1 yr^–1） could maintain soil P status at the most. The average soil P fractions comprised of extractable Pi, Po, and Pre by 51.7, 33.4, and 14.9% in total soil P, respectively. With comparison of no fertilizer addition（CK）, long-term single fertilization significantly（P〈0.05） increased the accumulation of Na HCO3^–, Na OH^–, and HCl^– extractable Pi fractions accounting for two- to three-fold, while SG increased the accumulation of Na HCO3^– and Na OH^– extractable Piand Po accounting for 12–60%. Though the mobilization of Pre fractions was not significant（P〉0.05）, our data indicate that SG may partially substitute for fertilizer P input and minimizing soil P accumulation and subsequent environmental risk in the subtropical paddy soil.
基金supported by the National Key Plan for Research and Development of China(No.2022YFD1900602)the National Natural Science Foundation of China(Nos.42020104004,52022028,51779077,and 41501328)。
文摘Biological nitrogen(N)fixation(BNF)driven by diazotrophs is an important pathway for N input in agricultural ecosystems.However,free-living BNF and its associated diazotrophic communities under different fertilization practices in acidic soils are poorly studied.Here,we conducted a long-term(29 years)fertilization experiment to explore how fertilization affected free-living BNF via changing biotic and abiotic variables.The fertilization treatments included an unfertilized control(CK),chemical N,phosphorus(P),and potassium(K)fertilizers(NPK),NPK plus lime(NPKL),NPK plus straw(NPKS),NPK plus straw and lime(NPKSL),and NPK plus manure(NPKM).Compared with CK(1.51 nmol C_(2)H_(2)g^(-1)d^(-1)),BNF rate was significantly(P<0.05)higher in NPKM(1.99 nmol C_(2)H_(2)g^(-1)d^(-1))but lower in NPK(0.55 nmol C_(2)H_(2)g^(-1)d^(-1)),NPKL(0.61 nmol C_(2)H_(2)g^(-1)d^(-1)),and NPKS(0.69nmol C_(2)H_(2)g^(-1)d^(-1)).Similarly,chemical fertilization treatments without manure reduced the gene abundance(0.71×10^(8)-1.18×10^(8)copies g^(-1))andα-diversity(Shannon index,1.11-2.43)of diazotrophic communities,whereas the treatment with manure had a positive effect on diazotrophic abundance(3.23×10^(8)copies g^(-1))and Shannon index(3.36).Non-parametric multivariate analysis of variance(PERMANOVA)suggested that manure application(R^(2)=0.212,P=0.001)had a stronger influence on diazotrophic community composition than the addition of lime(R^(2)=0.115,P=0.019)or straw(R^(2)=0.064,P=0.161).Random forest modeling revealed that BNF rates can be significantly(P<0.05)explained by soil pH(9.9%),diazotrophic community attributes(composition,8.5%;Chao 1 index,8.1%;abundance,6.0%;Shannon index,5.7%),and soil total carbon(5.1%).Partial least squares path modeling(PLS-PM)suggested that the diazotrophic community attributes and soil properties mainly provided direct and indirect contributions to the variations in BNF rates,respectively.The dominant genera,Pelomonas,Azospirillum,and Dechloromonas,were positively associated with BNF rates,with their members being observed as keystone species in the community network.Application of chemical fertilizers combined with manure is an effective practice for improving BNF in acidic soils by affecting soil diazotrophic communities.
基金Supported by Sichuan Science and Technology Program(2021YFN0017)Mutton Sheep High-Quality and High-Yield Forage Variety Selection and Production Application Post of Sichuan Mutton Sheep Innovation Team(sccxtd-2020-14)
文摘Utilizing straw as feed and applying cattle and sheep manure fertilizer to the field plays an important role in solving the shortage of feed raw material resources,alleviating the conflict between human beings and livestock,and realizing the full utilization of straw as a resource and green and low-carbon circular development.We carried out an investigation on the feed utilization of crop straw in Sichuan Province,comprehensively grasped the crop straw resources and its utilization as feed in this province,deeply analyzed the existing problems,and put forward countermeasures and suggestions according to the actual situation in Sichuan,which plays an important role in accelerating the process of straw feed utilization,promoting green development,implementing the rural revitalization strategy,and building a beautiful Sichuan.
基金supported by the National Key Research and Development Program of China(2017YFD0800404)the National Natural Science Foundation of China(41671249)Fundamental Research Funds for the Central Universities(2019QNA6011).
文摘Long-term application of chemical fertilizers causes soil degradation and nitrogen(N)loss,but these effects could be alleviated by organic fertilizers.In addition,crop rotation is a feasible practice to increase soil fertility,soil quality and crop yields comparing with monocultural cropping patterns.However,questions remain concerning how the soil microbiome responds to different manure application rates under crop rotations.Here,we collected soil samples from a rice-rape system to investigate the response of the soil microbiome to nine years of pig manure application at different rates(CK:0 kg ha^(-1),M1:1930 kg ha^(-1),M2:3860 kg ha^(-1) and M3:5790 kg ha^(-1)).Our results revealed that the bacterialα-diversity(Chao1 and Shannon index)in the rape season increased first and then decreased with increasing manure application rates,and a high manure load tended to decrease the bacterialα-diversity in the rice season.Long-term manure application enriched some copiotrophic bacteria,such as Proteobacteria and Actinobacteria,while it decreased the relative abundance of Nitrospirae.Redundancy analysis(RDA)and the Mantel test indicated that soil pH,TC,TN,AP,C/P and N/P ratios were the main factors influencing bacterial communities.Moreover,network analysis showed that a low manure application rate shaped a complexly connected and stable bacterial community,while higher manure application rate decreased the stability of the bacterial network.These findings improve our understanding of bacterial responses to longterm manure application under crop rotations and their relationships with soil factors,especially in the context of increasing fertilizer inputs.
文摘Greenhouse gas emissions （GHGs） from swine production systems are relatively well researched with the exception of emissions from land application of manure. GttGs inventories are needed for process- based modeling and science-based regulations. Thus, the objective of this observational study was to measure GHG fluxes from land application of swine manure on a typical corn field. Assessment of GHG emissions from deep injected land-applied swine manure, Phil and reapplication in the spring, on a typical US Midwestern corn-on-corn farm was completed. Static chambers were used Ibr flux measurement along with gas analysis on a GC-FID-ECD＋ Measured gas concentrations were used to estimate GHGs flux using four different models： linear regression, nonlinear regression, first order linear regression and the revised Hutchinson and Mosier （HMR） model, respectively for comparisons.Cumulative flux esmnates after manure apphcatmn of 5.85×10 g·ha^-1（1 ha = 0.01 km） of CO2 6.60×10^1g·ha^-1 of CH4 and3.48 ×10^3g·ha^-1 N2O for the fall trial and 3.11×10^6g·ha^-1 of CO2,2.95×10^3g·ha^-1 of OH4, and 1.47×10^4g·ha^-1 N2O after the spnng reapphcation trial were observed. The N2O net cumulative flux represents 0.595% of nitrogen applied in swine manure for the fall trial.
基金supported by the National Natural Science Foundation of China(Grant Nos.42477335,42077088)the Zhejiang Province“Agriculture,Rural Areas,Rural People and Nine Institutions”Science and Technology Collaboration Program(Grant No.2023SNJF039)X.P.L.was supported by a scholarship from the China Scholarship Council.
文摘Organic fertilization may influence soil carbon−iron(C-Fe)cycling and enhance phosphorus(P)availability,yet the direct connection between soil organic matter molecules and iron-reducing processes in long-term fertilized paddy soils remains underexplored.In this study,we conducted a microcosm experiment using paddy soils treated with six distinct fertilization regimes involving varying P and organic matter inputs up to five years.We assessed P activation under reflooding conditions,evaluated Fe reduction,and characterized dissolved organic matter(DOM)at the molecular level using Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS),alongside profiling soil microbial community composition via high-throughput sequencing.Our findings revealed that after 25 days of reflooding,soil Olsen-P content increased by an average of 73%compared to its initial state,showing a strong correlation with the Fe reduction process.Specifically,treatments involving pig manure application exhibited higher Fe reduction rates and enhanced P activation,highlighting the role of organic matter in facilitating Fe reduction.Examination of Fe-reducing microorganisms revealed that their relative abundance was decoupled from Fe reduction and P release rates,potentially due to limitations of lower soil organic matter content.Further analysis of DOM composition and network structures suggested that high-molecular-weight DOM,particularly lignin,acted as key resources for Fe-reducing microbes,thereby driving Fe reduction and promoting P release.Overall,our study highlights the crucial role of soil DOM in enabling microbial-driven Fe reduction and enhancing P availability,providing insights valuable for sustainable agricultural practices.
