Flooded soil samples were collected in the typical area of the Yangtze Delta Region; fractions of heavy metals in flooded and air dried samples were measured with BCR sequential extraction method and atomic absorption...Flooded soil samples were collected in the typical area of the Yangtze Delta Region; fractions of heavy metals in flooded and air dried samples were measured with BCR sequential extraction method and atomic absorption spectrometry. In flooded soils, fractions of heavy metals increased in the order of acid soluble 〈 oxidizable 〈 reducible 〈 residual. The acid soluble and reducible fractions significantly decreased but residual fraction significantly increased when the samples were air dried. The data obtained from air dried soil samples could not accurately represent the speciation of heavy metals in flooded field conditions.展开更多
Changes in soil organic carbon （SOC） of rice paddies in China were simulated from 1980 to 2000 by linking a coupled bio-physical model to GIS database. The coupled model consists of two sub-models including Crop-C f...Changes in soil organic carbon （SOC） of rice paddies in China were simulated from 1980 to 2000 by linking a coupled bio-physical model to GIS database. The coupled model consists of two sub-models including Crop-C for simulating net primary productivity and hence residue retention and Soil-C for computing the turnover rates of SOC. The GIS database included parameters of climate, soils and agricultural activities with the resolution of 10 km × 10 km. Model simulation indicated that Chinese rice paddies covering 22.6 Mha sequestrated a considerable amount of C, about 0.15 ± 0.07 Pg C from 1980 to 2000. Annual sequestration rate increased sharply from -180 ± 45 kg C ha^-1 year^-1 in 1980 to 440 ± 170 kg C ha^-1 year^-1 in 1989. Thereafter, a steaziy sequestration rate of 460 ± 170 kg C ha^-1 year^-1 occurred till 1994 and declined since then. Approximately 84% of the Chinese rice paddies sequestrated carbon, while 15% lost carbon and 1% kept balance over the 20 years. Great SOC sequestration occurred in eastern, southern and central China, while a slight decline of SOC existed in some regions of northeastern and southwestern China.展开更多
Rice paddy soil is recognized as the hotspot of mercury（Hg） methylation, which is mainly a biotic process mediated by many abiotic factors. In this study, effects of key soil properties on the production and bioaccu...Rice paddy soil is recognized as the hotspot of mercury（Hg） methylation, which is mainly a biotic process mediated by many abiotic factors. In this study, effects of key soil properties on the production and bioaccumulation of Hg and methylmercury（MeHg） in Hg-contaminated rice paddies were investigated. Rice and soil samples were collected from the active Hg smelting site and abandoned Hg mining sites（a total of 124 paddy fields） in the Wanshan Mercury Mine, China. Total Hg（THg） and MeHg in soils and rice grains, together with sulfur（S）,selenium（Se）, organic matter（OM）, nitrogen（N）, phosphorus（P）, mineral compositions（e.g., SiO2, Al2O3 and Fe2O3） and pH in soils were quantified. The results showed that long-term Hg mining activities had resulted in THg and MeHg contaminations in soil-rice system. The newly-deposited atmospheric Hg was more readily methylated relative to the native Hg already in soils, which could be responsible for the elevated MeHg levels in soils and rice grains around the active artificial Hg smelting site. The MeHg concentrations in soils and rice grains showed a significantly negative relationship with soil N/Hg, S/Hg and OM/Hg ratio possibly due to the formation of low-bioavailability Hg–S（N）–OM complexes in rhizosphere. The Hg–Se antagonism undoubtedly occurred in soil-rice system, while its role in bioaccumulation of MeHg in the MeHg-contaminated rice paddies was minor. However, other soil properties showed less influence on the production and bioaccumulation of MeHg in rice paddies located at the Wanshan Mercury Mine zone.展开更多
In the current study,the ecosystem services(ES) of conventional and organic rice paddies in Wannian,Jiangxi Province,China are investigated.First,the ES at the field level under organic and conventional paddies were i...In the current study,the ecosystem services(ES) of conventional and organic rice paddies in Wannian,Jiangxi Province,China are investigated.First,the ES at the field level under organic and conventional paddies were investigated.Total economic value of ES in organic rice paddies was 30093.08 yuan RMB/ha per year and that of conventional rice paddies was 22 793.31 yuan RMB/ha per year.The total indirect value of ES was 14 813.7 yuan RMB/ha per year in organic rice paddies and 12 424.56 yuan RMB/ha per year in conventional ones.There were significant differences between organic and conventional rice paddies for the economic values.Then,this economic information was used to extrapolate and to calculate the total and indirect value of ES from rice paddies in Wangnian.The total and indirect economic values of ES from conventional rice paddies in Wannian were 6791 million and 3702 million yuan RMB per year respectively,and the total and indirect economic values of ES from organic rice paddies in Wannian were 1311 million and 646 million yuan RMB per year.If half the area had being converted to organic farming in Wannian,the total and indirect economic values of ES from conventional rice paddies were 3397 million and 1851 million yuan RMB per year,and the total and indirect economic values of ES from organic rice paddies were 5794 million and 2852 million yuan RMB per year.Finally,the total economic value of ES in rice paddies in Wannian was demonstrated through geographic information system techniques.展开更多
Rice(Oryza sativa L.)paddies are increasingly threatened by cadmium(Cd)pollution,and potentially serve as CH_(4)emitters to the atmosphere.Remediation agents widely mitigate Cd pollution in paddy soil,however,we know ...Rice(Oryza sativa L.)paddies are increasingly threatened by cadmium(Cd)pollution,and potentially serve as CH_(4)emitters to the atmosphere.Remediation agents widely mitigate Cd pollution in paddy soil,however,we know little about their regulations on CH_(4)emission.Here,via adding biochar(B),sulfhydryl-modified palygorskite(SMP),and selenium foliar fertilizer(SFF),we conducted a pot experiment to investigate soil and rice Cd contents together with in-situ CH_(4)f luxes.Compared to CK,the addition of SMP,SFF,and B-SMP reduced Cd in brown rice by 25%to 50%,25%,and 50%to 75%,respectively.Agents 7%B,7%B-0.01%SMP,and SFF reduced CH_(4)emissions by 8.46%,5.30%,and 4.11%,respectively.CH_(4)emission increased gradually along the growing season,with the cumulative CH_(4)fluxes ranging between 338.82 and 619.13 kg hm^(-2).Our results highlight that mixed 7%B-0.01%SMP and SFF showed collaborative eff ects on Cd remediation and CH_(4)emission.This study reveals the feasibility of reducing Cd pollution and CH_(4)emission in karst rice paddies,which hopes to supplement the knowledge of collaborative controls on soil remediation and carbon emission.展开更多
Based on reference review, this study investigated ecosystem services supported by 10 typical rice paddies in six rice planting regions of China. The services were primary production, gas regulation, nitrogen transfor...Based on reference review, this study investigated ecosystem services supported by 10 typical rice paddies in six rice planting regions of China. The services were primary production, gas regulation, nitrogen transformation, soil organic matter accumulation, and water regulation and flood control. The results indicated that grain production of the 10 rice paddies was between 4.71 and 12.18 t ha^-1 y^-1; straw production was 4.65 to 9.79 t ha^-1 y^-1; gas regulation was calculated to emit O2 ranging from 8.27 to 19.69 t ha^-1 y^-1 and to assimilate greenhouse gases ranging from -2.13 to 19.24 t ha^-1 y^-1 （in CO2 equivalent）; nitrogen transformation was estimated as nitrogen input ranging from 209.70 to 513.93 kg N ha^-1 y^-1 and nitrogen output of 112.87 to 332.69 kg N ha^-1 y^-1; soil organic matter accumulation was calculated to be between 0.69 and 4.88 t C ha^-1 y^-1; water regulation was estimated to consume water resources of 19875 m3 ha^-1 y^-1 and to support water resources of 6430 m3 ha^-1 y^-1; and flood control of several of the rice paddies was calculated to be 1500 m3 ha^-1 y^-1. The integrated economic value of ecosystem services of these rice paddies was estimated at USD 8605–21 405 ha^-1 y^-1, of which 74%–89% of the value can be ascribed to ecosystem services outside primary production. The results also indicated that the integrated economic value of the ecosystem services of the 10 rice paddies was higher when nitrogen fertilizer was applied in the range of 275 to 297 kg N ha^-1. Until now, the economic value of the rice paddy ecosystem has been underestimated as only the economic value of grain and straw production was previously calculated. As more and more forest land and grassland is lost to urban and industrial use, cropland and especially rice paddies, will become more ecologically important to society. The economic value of ecosystem services supplied by rice paddies, outside primary production, are worthy of increased research attention.展开更多
A number of ancient charred paddies with a 14C dating of about 5900 a BP were recovered in the sixth excavation at Chuodun Site and are assigned to the Majiabang culture(7-6 ka BP).To understand their formation mechan...A number of ancient charred paddies with a 14C dating of about 5900 a BP were recovered in the sixth excavation at Chuodun Site and are assigned to the Majiabang culture(7-6 ka BP).To understand their formation mechanism,the ancient charred paddies were compared to modern paddies using FT-IR spectrum and thermaogravimetric analysis.At the same time,modern charred paddies were made in helium by the laboratory method,and the structural characteristics of them and the ancient ones were revealed using CP/MAS-13C-NMR.Our results show there are more aromatic moieties in ancient charred paddies compared to modern paddies.The aliphatic components of modern charred paddies decrease continuously,accompanied by the accumulation of aromatic components,when the duration and temperature of oxidation increase,and the structure buildings of modern charred paddies are more similar to ancient ones.Given the planting manner of paddies during Majiabang culture period,these ancient charred paddies might be a result of the original farming mode involving fire.展开更多
Seaweed extract contains plant growth regulators and bio-stimulants that enhance plant growth and development.In Bangladesh,winter rice(Boro rice)in the nursery bed often shows poor seed emergence and weak seedling gr...Seaweed extract contains plant growth regulators and bio-stimulants that enhance plant growth and development.In Bangladesh,winter rice(Boro rice)in the nursery bed often shows poor seed emergence and weak seedling growth due to low temperature.This problem can be addressed by using seaweed extract as a seed priming agent and bio-stimulant.The objective of this study was to evaluate the effectiveness of seaweed extract(Crop Plus)on seed emergence,seedling growth,and vigor of winter rice in the nursery.Two experiments were conducted at Bangladesh Agricultural University using BRRI dhan89.The laboratory experiment consisted of 17 treatments combining three concentrations of Crop Plus(5000,10,000 and 15,000 ppm)and four priming durations(6,12,18,and 24 h),along with hydro-priming and a no priming as control.Seed priming with 15,000 ppm for 24 h produced the highest germination percentage and superior seedling growth traits.The nursery bed experiment comprised 11 treatments combining two doses(1 mL m^(−2)and 2 mL m^(−2))of Crop Plus and five different foliar application schedules,along with a control.All treatments outperformed the control,with the best results from Crop Plus@2 mL m^(−2)applied at 20 and 30 days after sowing(DAS).Overall,the treatment involving seed priming with 15,000 ppm seaweed extract for 24 h,followed by nursery application at 2 mL m^(−2)at 20 and 30 DAS,resulted in higher germination and improved early growth of winter rice.However,further validation across multiple locations,seasons,and rice cultivars is recommended.展开更多
Microorganisms carrying cbbL,pmoA and coxL genes play crucial roles in regulating soil-atmosphere exchanges of carbon trace gases(CO_(2),CH_(4),and CO).However,the geographical distribution patterns of these functiona...Microorganisms carrying cbbL,pmoA and coxL genes play crucial roles in regulating soil-atmosphere exchanges of carbon trace gases(CO_(2),CH_(4),and CO).However,the geographical distribution patterns of these functional genes in agricultural ecosystems and their environmental drivers remain poorly understood.Here,we surveyed agricultural soils across four climate zones(tropical,subtropical,warm temperate,and mid-temperate)in eastern China to quantify the abundances of CO_(2)-assimilating bacteria(cbbL gene),methanotrophs(pmoA gene),and CO-oxidizing bacteria(coxL gene).We found significant ecosystem-specific patterns:the cbbL gene was more abundant in upland soils(averaging 9.46×10^(9)copies g^(–1))than in paddy soils(6.44×10^(9) copies g^(–1)).In contrast,methanotrophs abundance was 1 to 3 orders of magnitude higher in paddy(averaging 1.17×10^(8) copies g^(–1))than in upland(5.78×10^(6)copies g^(–1))soils.The coxL gene maintained similar abundance levels across both soil types(averaging 6.12×10^(8) vs.5.91×10^(8) copies g^(–1)).Structural equation models revealed that spatial factors primarily shaped cbbL and pmoA in uplands,whereas total bacterial abundance was the dominant predictor for all three genes in paddy soils.These results highlight distinct ecological controls on microbial functional groups and provide a predictive framework for how land use and climate change may regulate microbial mediation of carbon gas fluxes across a continental-scale transect in eastern China.展开更多
Rapidly improving infertile croplands and enhancing their soil organic carbon(SOC)pool necessitate substantial organic materials incorporation.Converting loose crop straw into granulated form facilitates uniform incor...Rapidly improving infertile croplands and enhancing their soil organic carbon(SOC)pool necessitate substantial organic materials incorporation.Converting loose crop straw into granulated form facilitates uniform incorporation within the plough soil layer.As an innovative soil amelioration approach,the efficiency and patterns of SOC accumulation remain unclear.Two field experiments were conducted in infertile subtropical upland and paddy soils with 0,30,60,and 90 Mg ha^(-1)granulated straw incorporation.After one year,SOC accumulation efficiency from straw input remained stable in upland(30.8–37.5%)with increasing amounts of straw incorporation,while declined from 60.0 to 38.3%in paddy.In both croplands,the contributions of lignin phenols to SOC increased with increasing straw incorporation,while the contributions from amino sugars remained constant at higher straw input levels.Subsequently,the ratios of lignin phenols to amino sugars increased with increasing straw incorporation,indicating faster plant residue accumulation compared to microbial necromass,as the granulation approach limited microbial involvement in straw transformation.Thus,single-time incorporation of substantial granulated straw presents an effective agricultural strategy for rapid amelioration of infertile croplands.展开更多
Nitrogen use efficiency in rice is lower than in upland crops,likely due to differences in soil nitrogen dynamics and crop nitrogen preferences.However,the specific nitrogen dynamics in paddy and upland systems and th...Nitrogen use efficiency in rice is lower than in upland crops,likely due to differences in soil nitrogen dynamics and crop nitrogen preferences.However,the specific nitrogen dynamics in paddy and upland systems and their impact on crop nitrogen uptake remain poorly understood.The N dynamics and impact on crop N uptake determine the downstream environmental pollution from nitrogen fertilizer.To address this poor understanding,we analyzed 2,044 observations of gross nitrogen transformation rates in soils from 136 studies to examine nitrogen dynamics in both systems and their effects on nitrogen uptake in rice and upland crops.Our findings revealed that nitrogen mineralization and autotrophic nitrification rates are lower in paddies than in upland soil,while dissimilatory nitrate reduction to ammonium is higher in paddies,these differences being driven by flooding and lower total nitrogen content in paddies.Rice exhibited higher ammonium uptake,while upland crops had over twice the nitrate uptake.Autotrophic nitrification stimulated by p H reduced rice nitrogen uptake,while heterotrophic nitrification enhanced nitrogen uptake of upland crops.Autotrophic nitrification played a key role in regulating the ammonium-to-nitrate ratio in soils,which further affected the balance of plant nitrogen uptake.These results highlight the need to align soil nitrogen dynamics with crop nitrogen preferences to maximize plant maximize productivity and reduce reactive nitrogen pollution.展开更多
From rice paddies to poultry farms,an ambitious generation of Tanzanian youth is cultivating dreams of agricultural entrepreneurship A tender breeze sweeps across Zanzibar’s golden paddies at sunrise,carrying with it...From rice paddies to poultry farms,an ambitious generation of Tanzanian youth is cultivating dreams of agricultural entrepreneurship A tender breeze sweeps across Zanzibar’s golden paddies at sunrise,carrying with it the calm rhythm of a new day.展开更多
From July to September of 1990,CH_4 flux measurements were made in Lin'an rice paddies using gradient profile techniques.Some characteristics of the turbulence structure under the stable conditions have been verif...From July to September of 1990,CH_4 flux measurements were made in Lin'an rice paddies using gradient profile techniques.Some characteristics of the turbulence structure under the stable conditions have been verified in the surface layer according to the in situ measurements.The semi-empirical turbulent parameters β_m,β_h and β_c and their changes with the stability parameter Ri are given.Observed results indicate that CH_4 flux in the rice-paddy is mainly decided by the methnogenesis and the process of CH4 transport from internal soils to the atmosphere,and that the CH_4 vertical transfer is depressed in the stable surface layer.The CH_4 flux shows that its obvious diurnal changes,and the mean CH_4 flux are higher in nighttime and lower in daytime,and the peaks appear at about 2000 BST at night and 0300 BST in the early morning,respectively.The mean value of CH_4 flux is about 4.18±2.3 mg/m^2 h.展开更多
Adoption of Chinese hybrid rice boosts food security in Madagascar As the sun rises over the rice paddies of Mahitsy,Ramos Rakotorinina breathes in the cool morning air,watching the emerald green shoots of Chinese hyb...Adoption of Chinese hybrid rice boosts food security in Madagascar As the sun rises over the rice paddies of Mahitsy,Ramos Rakotorinina breathes in the cool morning air,watching the emerald green shoots of Chinese hybrid rice sway softly in the breeze.展开更多
The demand for pesticides in China hasshrunk this year. The resulting fiercer competitionbetween herbicide varieties has ledto a significant price reduction in mostherbicides. The sales and the price of threerice padd...The demand for pesticides in China hasshrunk this year. The resulting fiercer competitionbetween herbicide varieties has ledto a significant price reduction in mostherbicides. The sales and the price of threerice paddy herbicides including butachlor, quinclorac and cinosulfuron have grownhowever. This phenomenon may be closelyrelated to the fact that rice is the most importantgrain crop in China. Rice grows展开更多
Winter planting green manures in southern China effectively improve soil properties and rice production through microbial community construction.However,the effects of soil communities of arbuscular mycorrhizal fungi(...Winter planting green manures in southern China effectively improve soil properties and rice production through microbial community construction.However,the effects of soil communities of arbuscular mycorrhizal fungi(AMF)from different winter planting green manures on the soil properties and post-cropping rice production remain unclear.In this study,the soil AMF communities of three common winter planting patterns in southern China,winter fallow,winter ryegrass(Lolium multiflorum L.),and winter Chinese milk vetch(Astragalus sinicus L.),were explored and their effects on post-cropping rice production were investigated.Compared with winter fallow,the winter ryegrass and winter Chinese milk vetch patterns could alleviate soil acidification,significantly increase soil AMF spore density,and improve the soil AMF community structure.Based on sterilized soil,rice production indicators such as thousandseed weight,theoretical yield,and the grain amylose and total sugar contents of rice inoculated with AMF spores from winter Chinese milk vetch soil were 6.68–53.57%higher than those without AMF inoculation.Rice panicle weight,seed setting rate,and theoretical yield were 15.38–22.71%higher in the treatment with AMF spores from winter ryegrass soil than in the treatments with no AMF inoculation.In addition,the protein,amylose,and total sugar contents of rice grains were 14.92,104.82,and 802.23 mg kg^(–1),respectively,which were 31.31,14.25 and 34.47%higher than those without AMF inoculation.The AMF community dominated by Glomus and Acaulospora in winter Chinese milk vetch had a more positive effect on the improvement of rice yield,while the AMF community dominated by Glomus in winter ryegrass soil was more conducive to rice quality improvement.These findings have revealed the critical role of AMF communities from green manure in rice production,which lays the theoretical basis for a promising strategy to promote the sustainable development of southern winter agriculture.展开更多
In the process of promoting the rural revitalization strategy,paddy filed landscapes,as the most representative form of productive landscape in rural areas,not only serve the function of grain production,but also hold...In the process of promoting the rural revitalization strategy,paddy filed landscapes,as the most representative form of productive landscape in rural areas,not only serve the function of grain production,but also hold significant value in ecological protection,cultural inheritance,and industrial integration.Taking Xiangling Village in Huizhou,Guangdong Province as the research object,this study analyzes the current status and existing problems of the paddy field landscapes through field research.Combining with the overall requirements of rural revitalization of“vibrant local industries,pleasant living environments,social etiquette and civility,sound governance,and affluent living”,this study proposes paddy field landscape design strategies from four dimensions:industrial integration,ecological optimization,cultural empowerment,and spatial reconstruction,and constructs specific design plans to provide practical reference for the landscape improvement of similar rural areas.展开更多
This study aimed to explore the effect of different proportions of organic fertilizer replacing chemical fertilizer on the bacterial community and metabolic function in paddy fields.The 16S rRNA absolute quantitative ...This study aimed to explore the effect of different proportions of organic fertilizer replacing chemical fertilizer on the bacterial community and metabolic function in paddy fields.The 16S rRNA absolute quantitative sequencing method was employed to study the response characteristics of soil bacterial community composition and species absolute abundance to environmental factors under three fertilization treatments[chemical fertilizer(NPK),organic fertilizer replacing 30%of chemical fertilizer(30M,estimated in terms of pure nitrogen,same below),and organic fertilizer replacing 60%of chemical fertilizer(60M)]for two consecutive years.Furthermore,the changes of bacterial metabolic functions of different fertilization treatments were predicted by PICRUSt2.The results showed that replacing chemical fertilizer with organic fertilizer at different proportions significantly increased the total nitrogen(TN),total potassium(TK),hydrolyzable nitrogen(HN),soil organic carbon(SOC),and significantly decreased the soil bulk density(SBD).Moreover,60M demonstrated better performance than 30M.Different fertilization treatments did not cause significant difference in soil bacterial richness index(Chao1)or diversity index(Shannon)but significantly affected bacterial community composition and species abundance.Particularly,60M significantly increased the abundance of 227 species,and it increased the total bacterial abundance by 25.30%and 56.58%compared with NPK and 30M,respectively.Redundancy analysis and Spearman correlation analysis revealed that SOC,TN,and AK were the key factors for shaping specific bacterial community structures under different fertilization treatments.The 60M treatment significantly increased the abundance of bacterial species involved in xenobiotic biodegradation and metabolism,amino acid metabolism,and lipid metabolism,thus improving the metabolic functions of soil microorganisms.展开更多
In order to identify the nutrient level and environmental quality of paddy fields in Wanchang area,and to provide scientific basis and technical support for planting rice in Wanchang area, the soil geochemicalsurvey w...In order to identify the nutrient level and environmental quality of paddy fields in Wanchang area,and to provide scientific basis and technical support for planting rice in Wanchang area, the soil geochemicalsurvey was carried out, 30 samples were collected from paddy soil in Wanchang area, and 20 elements(indicators) were analyzed. The characterization of the elemental content of soils in the study area was carriedout, and the geochemical level for soil nutrients, the geochemical level for the soil environment, and thecomprehensive geochemical level of soil quality were evaluated. The results showed that the average valuesof K content and pH of the soil in the study area were smaller than the background values of Jilin Province,and the average values of 18 elements including N, P, Ca, S, Pb, Zn etc. were bigger than the backgroundvalues of Jilin Province. The results of the evaluation of soil single element nutrient in the study area showedthat the available state nutrient levels of Mn, Zn, Cu, and K increased compared with the total amounts ofnutrients level, with Cu increasing the most;the available state nutrient level of N, P, B, and Mo decreasedcompared with the total amounts of nutrients level, with Mo decreasing the most. The comprehensive levelof soil nutrients geochemistry in paddy fields was mainly Level III (medium), accounting for 53.33%, andthe low abundance level was caused by the lack of P element;the comprehensive level of soil environmentalgeochemistry was mainly Level I (clean), accounting for 96.67%, with only slight pollution caused byCd. The comprehensive geochemical level of soil quality was mainly Level II, accounting for 66.67%.Suggestions were put forward for the rational utilization of soil resources in paddy fields in the study area.展开更多
In natural ecosystems,the timely abscission of seeds in wild plants is a crucial adaptive trait that contributes to reproductive success,population renewal,and colony expansion(Thurber et al.2010).In contrast,the tend...In natural ecosystems,the timely abscission of seeds in wild plants is a crucial adaptive trait that contributes to reproductive success,population renewal,and colony expansion(Thurber et al.2010).In contrast,the tendency for high seed shattering in domesticated crops,such as rice,not only reduces paddy yield but also complicates mechanized harvesting.展开更多
基金funding from the Natural Science Foundation of China(No.41101491)
文摘Flooded soil samples were collected in the typical area of the Yangtze Delta Region; fractions of heavy metals in flooded and air dried samples were measured with BCR sequential extraction method and atomic absorption spectrometry. In flooded soils, fractions of heavy metals increased in the order of acid soluble 〈 oxidizable 〈 reducible 〈 residual. The acid soluble and reducible fractions significantly decreased but residual fraction significantly increased when the samples were air dried. The data obtained from air dried soil samples could not accurately represent the speciation of heavy metals in flooded field conditions.
基金Project supported by the Knowledge Innovation Program of the Chinese Academy of, Sciences (No. KZCX1-SW-01-13)the National Natural Science Foundation of China (No. 40431001)the National Key Basic Research Support Foundation of China (No. 2002CB412500).
文摘Changes in soil organic carbon （SOC） of rice paddies in China were simulated from 1980 to 2000 by linking a coupled bio-physical model to GIS database. The coupled model consists of two sub-models including Crop-C for simulating net primary productivity and hence residue retention and Soil-C for computing the turnover rates of SOC. The GIS database included parameters of climate, soils and agricultural activities with the resolution of 10 km × 10 km. Model simulation indicated that Chinese rice paddies covering 22.6 Mha sequestrated a considerable amount of C, about 0.15 ± 0.07 Pg C from 1980 to 2000. Annual sequestration rate increased sharply from -180 ± 45 kg C ha^-1 year^-1 in 1980 to 440 ± 170 kg C ha^-1 year^-1 in 1989. Thereafter, a steaziy sequestration rate of 460 ± 170 kg C ha^-1 year^-1 occurred till 1994 and declined since then. Approximately 84% of the Chinese rice paddies sequestrated carbon, while 15% lost carbon and 1% kept balance over the 20 years. Great SOC sequestration occurred in eastern, southern and central China, while a slight decline of SOC existed in some regions of northeastern and southwestern China.
基金supported by the National Natural Science Foundation of China (No.41763017)the Program Foundation of Institute for Scientific Research of Karst Area of NSFC-GZGOV (No.U1612442)+2 种基金the Science and Technology Planning Project of Guizhou Province (No.Qiankehe-[2018]2336)the Key Discipline Construction Project,Guizhou (No.ZDXK [2016]11)the Topclass Discipline Construction Project of Ecology in Guizhou Province (No.GNYL[2017]007)
文摘Rice paddy soil is recognized as the hotspot of mercury（Hg） methylation, which is mainly a biotic process mediated by many abiotic factors. In this study, effects of key soil properties on the production and bioaccumulation of Hg and methylmercury（MeHg） in Hg-contaminated rice paddies were investigated. Rice and soil samples were collected from the active Hg smelting site and abandoned Hg mining sites（a total of 124 paddy fields） in the Wanshan Mercury Mine, China. Total Hg（THg） and MeHg in soils and rice grains, together with sulfur（S）,selenium（Se）, organic matter（OM）, nitrogen（N）, phosphorus（P）, mineral compositions（e.g., SiO2, Al2O3 and Fe2O3） and pH in soils were quantified. The results showed that long-term Hg mining activities had resulted in THg and MeHg contaminations in soil-rice system. The newly-deposited atmospheric Hg was more readily methylated relative to the native Hg already in soils, which could be responsible for the elevated MeHg levels in soils and rice grains around the active artificial Hg smelting site. The MeHg concentrations in soils and rice grains showed a significantly negative relationship with soil N/Hg, S/Hg and OM/Hg ratio possibly due to the formation of low-bioavailability Hg–S（N）–OM complexes in rhizosphere. The Hg–Se antagonism undoubtedly occurred in soil-rice system, while its role in bioaccumulation of MeHg in the MeHg-contaminated rice paddies was minor. However, other soil properties showed less influence on the production and bioaccumulation of MeHg in rice paddies located at the Wanshan Mercury Mine zone.
基金supported by GEF/FAO project"Rice-fish GIAHS Conservation and Adaptive Management"(GCP/GCO/212/GEF)
文摘In the current study,the ecosystem services(ES) of conventional and organic rice paddies in Wannian,Jiangxi Province,China are investigated.First,the ES at the field level under organic and conventional paddies were investigated.Total economic value of ES in organic rice paddies was 30093.08 yuan RMB/ha per year and that of conventional rice paddies was 22 793.31 yuan RMB/ha per year.The total indirect value of ES was 14 813.7 yuan RMB/ha per year in organic rice paddies and 12 424.56 yuan RMB/ha per year in conventional ones.There were significant differences between organic and conventional rice paddies for the economic values.Then,this economic information was used to extrapolate and to calculate the total and indirect value of ES from rice paddies in Wangnian.The total and indirect economic values of ES from conventional rice paddies in Wannian were 6791 million and 3702 million yuan RMB per year respectively,and the total and indirect economic values of ES from organic rice paddies in Wannian were 1311 million and 646 million yuan RMB per year.If half the area had being converted to organic farming in Wannian,the total and indirect economic values of ES from conventional rice paddies were 3397 million and 1851 million yuan RMB per year,and the total and indirect economic values of ES from organic rice paddies were 5794 million and 2852 million yuan RMB per year.Finally,the total economic value of ES in rice paddies in Wannian was demonstrated through geographic information system techniques.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB40020200)the National Natural Science Foundation of China(41663015,42273021)+4 种基金Guizhou Science and Technology Cooperation Basic Project([2020]1Y188)the construction project of Key Laboratory of State Ethnic Aff airs Commission([2020]No 0.91 of DDA office)the Innovation Team Project of Guizhou Higher Education([2022]013)Foundation of Guizhou Minzu University(GZMU[2019]YB11)Thanks to the support of the independent deployment project of the State Key Laboratory of Environmental Geochemistry。
文摘Rice(Oryza sativa L.)paddies are increasingly threatened by cadmium(Cd)pollution,and potentially serve as CH_(4)emitters to the atmosphere.Remediation agents widely mitigate Cd pollution in paddy soil,however,we know little about their regulations on CH_(4)emission.Here,via adding biochar(B),sulfhydryl-modified palygorskite(SMP),and selenium foliar fertilizer(SFF),we conducted a pot experiment to investigate soil and rice Cd contents together with in-situ CH_(4)f luxes.Compared to CK,the addition of SMP,SFF,and B-SMP reduced Cd in brown rice by 25%to 50%,25%,and 50%to 75%,respectively.Agents 7%B,7%B-0.01%SMP,and SFF reduced CH_(4)emissions by 8.46%,5.30%,and 4.11%,respectively.CH_(4)emission increased gradually along the growing season,with the cumulative CH_(4)fluxes ranging between 338.82 and 619.13 kg hm^(-2).Our results highlight that mixed 7%B-0.01%SMP and SFF showed collaborative eff ects on Cd remediation and CH_(4)emission.This study reveals the feasibility of reducing Cd pollution and CH_(4)emission in karst rice paddies,which hopes to supplement the knowledge of collaborative controls on soil remediation and carbon emission.
基金Strategic Priority Research Program of the Chinese Academy of Sciences (XDA05050203)National Natural Science Foundation of China (31140048, 30770410 and 31070384)Innovation Project of Institute of Geographic Sciences and Natural Resources Research, CAS (200905010)
文摘Based on reference review, this study investigated ecosystem services supported by 10 typical rice paddies in six rice planting regions of China. The services were primary production, gas regulation, nitrogen transformation, soil organic matter accumulation, and water regulation and flood control. The results indicated that grain production of the 10 rice paddies was between 4.71 and 12.18 t ha^-1 y^-1; straw production was 4.65 to 9.79 t ha^-1 y^-1; gas regulation was calculated to emit O2 ranging from 8.27 to 19.69 t ha^-1 y^-1 and to assimilate greenhouse gases ranging from -2.13 to 19.24 t ha^-1 y^-1 （in CO2 equivalent）; nitrogen transformation was estimated as nitrogen input ranging from 209.70 to 513.93 kg N ha^-1 y^-1 and nitrogen output of 112.87 to 332.69 kg N ha^-1 y^-1; soil organic matter accumulation was calculated to be between 0.69 and 4.88 t C ha^-1 y^-1; water regulation was estimated to consume water resources of 19875 m3 ha^-1 y^-1 and to support water resources of 6430 m3 ha^-1 y^-1; and flood control of several of the rice paddies was calculated to be 1500 m3 ha^-1 y^-1. The integrated economic value of ecosystem services of these rice paddies was estimated at USD 8605–21 405 ha^-1 y^-1, of which 74%–89% of the value can be ascribed to ecosystem services outside primary production. The results also indicated that the integrated economic value of the ecosystem services of the 10 rice paddies was higher when nitrogen fertilizer was applied in the range of 275 to 297 kg N ha^-1. Until now, the economic value of the rice paddy ecosystem has been underestimated as only the economic value of grain and straw production was previously calculated. As more and more forest land and grassland is lost to urban and industrial use, cropland and especially rice paddies, will become more ecologically important to society. The economic value of ecosystem services supplied by rice paddies, outside primary production, are worthy of increased research attention.
基金Supported by the National Natural Science Foundation of China (Grant No.40571088)
文摘A number of ancient charred paddies with a 14C dating of about 5900 a BP were recovered in the sixth excavation at Chuodun Site and are assigned to the Majiabang culture(7-6 ka BP).To understand their formation mechanism,the ancient charred paddies were compared to modern paddies using FT-IR spectrum and thermaogravimetric analysis.At the same time,modern charred paddies were made in helium by the laboratory method,and the structural characteristics of them and the ancient ones were revealed using CP/MAS-13C-NMR.Our results show there are more aromatic moieties in ancient charred paddies compared to modern paddies.The aliphatic components of modern charred paddies decrease continuously,accompanied by the accumulation of aromatic components,when the duration and temperature of oxidation increase,and the structure buildings of modern charred paddies are more similar to ancient ones.Given the planting manner of paddies during Majiabang culture period,these ancient charred paddies might be a result of the original farming mode involving fire.
基金funded by Bangladesh Agricultural University Research System(BAURES)through the Project No.2024/48/BAU.
文摘Seaweed extract contains plant growth regulators and bio-stimulants that enhance plant growth and development.In Bangladesh,winter rice(Boro rice)in the nursery bed often shows poor seed emergence and weak seedling growth due to low temperature.This problem can be addressed by using seaweed extract as a seed priming agent and bio-stimulant.The objective of this study was to evaluate the effectiveness of seaweed extract(Crop Plus)on seed emergence,seedling growth,and vigor of winter rice in the nursery.Two experiments were conducted at Bangladesh Agricultural University using BRRI dhan89.The laboratory experiment consisted of 17 treatments combining three concentrations of Crop Plus(5000,10,000 and 15,000 ppm)and four priming durations(6,12,18,and 24 h),along with hydro-priming and a no priming as control.Seed priming with 15,000 ppm for 24 h produced the highest germination percentage and superior seedling growth traits.The nursery bed experiment comprised 11 treatments combining two doses(1 mL m^(−2)and 2 mL m^(−2))of Crop Plus and five different foliar application schedules,along with a control.All treatments outperformed the control,with the best results from Crop Plus@2 mL m^(−2)applied at 20 and 30 days after sowing(DAS).Overall,the treatment involving seed priming with 15,000 ppm seaweed extract for 24 h,followed by nursery application at 2 mL m^(−2)at 20 and 30 DAS,resulted in higher germination and improved early growth of winter rice.However,further validation across multiple locations,seasons,and rice cultivars is recommended.
基金financially supported by the National Key R&D Program of China(2023YFD1902802)the Science Fund for Distinguished Young Scholars in Hunan,China(2024JJ2052)+3 种基金the Natural Science Foundation of Fujian Province,China(2022J05263)the Nanping City Science and Technology Plan Project,China(NP2021KTS02)the Talent Introduction Project of Wuyi University,China(YJ202117)the Open Foundation of State Key Laboratory of Microbial Technology in Shandong University,China(M2022-05)。
文摘Microorganisms carrying cbbL,pmoA and coxL genes play crucial roles in regulating soil-atmosphere exchanges of carbon trace gases(CO_(2),CH_(4),and CO).However,the geographical distribution patterns of these functional genes in agricultural ecosystems and their environmental drivers remain poorly understood.Here,we surveyed agricultural soils across four climate zones(tropical,subtropical,warm temperate,and mid-temperate)in eastern China to quantify the abundances of CO_(2)-assimilating bacteria(cbbL gene),methanotrophs(pmoA gene),and CO-oxidizing bacteria(coxL gene).We found significant ecosystem-specific patterns:the cbbL gene was more abundant in upland soils(averaging 9.46×10^(9)copies g^(–1))than in paddy soils(6.44×10^(9) copies g^(–1)).In contrast,methanotrophs abundance was 1 to 3 orders of magnitude higher in paddy(averaging 1.17×10^(8) copies g^(–1))than in upland(5.78×10^(6)copies g^(–1))soils.The coxL gene maintained similar abundance levels across both soil types(averaging 6.12×10^(8) vs.5.91×10^(8) copies g^(–1)).Structural equation models revealed that spatial factors primarily shaped cbbL and pmoA in uplands,whereas total bacterial abundance was the dominant predictor for all three genes in paddy soils.These results highlight distinct ecological controls on microbial functional groups and provide a predictive framework for how land use and climate change may regulate microbial mediation of carbon gas fluxes across a continental-scale transect in eastern China.
基金financially supported by the National Key R&D Program of China(2021YFD1901203 and 2021YFD1901204)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA0440404)+2 种基金the National Natural Science Foundation of China(42377348)the Science Foundation for Distinguished Young Scholars of Hunan Province,China(2024JJ2052)the Natural Science Foundation of Guangxi,China(2025GXNSFAA069337)。
文摘Rapidly improving infertile croplands and enhancing their soil organic carbon(SOC)pool necessitate substantial organic materials incorporation.Converting loose crop straw into granulated form facilitates uniform incorporation within the plough soil layer.As an innovative soil amelioration approach,the efficiency and patterns of SOC accumulation remain unclear.Two field experiments were conducted in infertile subtropical upland and paddy soils with 0,30,60,and 90 Mg ha^(-1)granulated straw incorporation.After one year,SOC accumulation efficiency from straw input remained stable in upland(30.8–37.5%)with increasing amounts of straw incorporation,while declined from 60.0 to 38.3%in paddy.In both croplands,the contributions of lignin phenols to SOC increased with increasing straw incorporation,while the contributions from amino sugars remained constant at higher straw input levels.Subsequently,the ratios of lignin phenols to amino sugars increased with increasing straw incorporation,indicating faster plant residue accumulation compared to microbial necromass,as the granulation approach limited microbial involvement in straw transformation.Thus,single-time incorporation of substantial granulated straw presents an effective agricultural strategy for rapid amelioration of infertile croplands.
基金funded by the National Key Research and Development Program of China(2024YFD1501602)the National Natural Science Foundation of China(42407437)conducted as part of the Coordinated Research Project D1.50.16,implemented by the Soil and Water Management and Crop Nutrition Section of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture,Department of Nuclear Sciences and Applications,Vienna,Austria。
文摘Nitrogen use efficiency in rice is lower than in upland crops,likely due to differences in soil nitrogen dynamics and crop nitrogen preferences.However,the specific nitrogen dynamics in paddy and upland systems and their impact on crop nitrogen uptake remain poorly understood.The N dynamics and impact on crop N uptake determine the downstream environmental pollution from nitrogen fertilizer.To address this poor understanding,we analyzed 2,044 observations of gross nitrogen transformation rates in soils from 136 studies to examine nitrogen dynamics in both systems and their effects on nitrogen uptake in rice and upland crops.Our findings revealed that nitrogen mineralization and autotrophic nitrification rates are lower in paddies than in upland soil,while dissimilatory nitrate reduction to ammonium is higher in paddies,these differences being driven by flooding and lower total nitrogen content in paddies.Rice exhibited higher ammonium uptake,while upland crops had over twice the nitrate uptake.Autotrophic nitrification stimulated by p H reduced rice nitrogen uptake,while heterotrophic nitrification enhanced nitrogen uptake of upland crops.Autotrophic nitrification played a key role in regulating the ammonium-to-nitrate ratio in soils,which further affected the balance of plant nitrogen uptake.These results highlight the need to align soil nitrogen dynamics with crop nitrogen preferences to maximize plant maximize productivity and reduce reactive nitrogen pollution.
文摘From rice paddies to poultry farms,an ambitious generation of Tanzanian youth is cultivating dreams of agricultural entrepreneurship A tender breeze sweeps across Zanzibar’s golden paddies at sunrise,carrying with it the calm rhythm of a new day.
基金The project is sponsored by the National Natural Science Foundation of China.
文摘From July to September of 1990,CH_4 flux measurements were made in Lin'an rice paddies using gradient profile techniques.Some characteristics of the turbulence structure under the stable conditions have been verified in the surface layer according to the in situ measurements.The semi-empirical turbulent parameters β_m,β_h and β_c and their changes with the stability parameter Ri are given.Observed results indicate that CH_4 flux in the rice-paddy is mainly decided by the methnogenesis and the process of CH4 transport from internal soils to the atmosphere,and that the CH_4 vertical transfer is depressed in the stable surface layer.The CH_4 flux shows that its obvious diurnal changes,and the mean CH_4 flux are higher in nighttime and lower in daytime,and the peaks appear at about 2000 BST at night and 0300 BST in the early morning,respectively.The mean value of CH_4 flux is about 4.18±2.3 mg/m^2 h.
文摘Adoption of Chinese hybrid rice boosts food security in Madagascar As the sun rises over the rice paddies of Mahitsy,Ramos Rakotorinina breathes in the cool morning air,watching the emerald green shoots of Chinese hybrid rice sway softly in the breeze.
文摘The demand for pesticides in China hasshrunk this year. The resulting fiercer competitionbetween herbicide varieties has ledto a significant price reduction in mostherbicides. The sales and the price of threerice paddy herbicides including butachlor, quinclorac and cinosulfuron have grownhowever. This phenomenon may be closelyrelated to the fact that rice is the most importantgrain crop in China. Rice grows
基金supported by the National Natural Science Foundation of China(32171683)the Shenzhen Science and Technology Program,China(JCYJ20220530145606015)+4 种基金the Agricultural and Social Development Project of Guangzhou Municipal Science and Technology Bureau,China(202206010058)the Special Fund for Agro-scientific Research in the Public Interest of China(201503122)the Natural Science Foundation of Guangdong Province,China(2020A1515010494)the Yangfan Innovative&Entrepreneurial Research Team Project,China(2015YT02H032)the Zhang Hong-da Science Research Fund of Sun Yat-sen University,China。
文摘Winter planting green manures in southern China effectively improve soil properties and rice production through microbial community construction.However,the effects of soil communities of arbuscular mycorrhizal fungi(AMF)from different winter planting green manures on the soil properties and post-cropping rice production remain unclear.In this study,the soil AMF communities of three common winter planting patterns in southern China,winter fallow,winter ryegrass(Lolium multiflorum L.),and winter Chinese milk vetch(Astragalus sinicus L.),were explored and their effects on post-cropping rice production were investigated.Compared with winter fallow,the winter ryegrass and winter Chinese milk vetch patterns could alleviate soil acidification,significantly increase soil AMF spore density,and improve the soil AMF community structure.Based on sterilized soil,rice production indicators such as thousandseed weight,theoretical yield,and the grain amylose and total sugar contents of rice inoculated with AMF spores from winter Chinese milk vetch soil were 6.68–53.57%higher than those without AMF inoculation.Rice panicle weight,seed setting rate,and theoretical yield were 15.38–22.71%higher in the treatment with AMF spores from winter ryegrass soil than in the treatments with no AMF inoculation.In addition,the protein,amylose,and total sugar contents of rice grains were 14.92,104.82,and 802.23 mg kg^(–1),respectively,which were 31.31,14.25 and 34.47%higher than those without AMF inoculation.The AMF community dominated by Glomus and Acaulospora in winter Chinese milk vetch had a more positive effect on the improvement of rice yield,while the AMF community dominated by Glomus in winter ryegrass soil was more conducive to rice quality improvement.These findings have revealed the critical role of AMF communities from green manure in rice production,which lays the theoretical basis for a promising strategy to promote the sustainable development of southern winter agriculture.
基金Sponsored by Huizhou City Science and Technology Project for the Social Development Sector(2023CQ010009).
文摘In the process of promoting the rural revitalization strategy,paddy filed landscapes,as the most representative form of productive landscape in rural areas,not only serve the function of grain production,but also hold significant value in ecological protection,cultural inheritance,and industrial integration.Taking Xiangling Village in Huizhou,Guangdong Province as the research object,this study analyzes the current status and existing problems of the paddy field landscapes through field research.Combining with the overall requirements of rural revitalization of“vibrant local industries,pleasant living environments,social etiquette and civility,sound governance,and affluent living”,this study proposes paddy field landscape design strategies from four dimensions:industrial integration,ecological optimization,cultural empowerment,and spatial reconstruction,and constructs specific design plans to provide practical reference for the landscape improvement of similar rural areas.
文摘This study aimed to explore the effect of different proportions of organic fertilizer replacing chemical fertilizer on the bacterial community and metabolic function in paddy fields.The 16S rRNA absolute quantitative sequencing method was employed to study the response characteristics of soil bacterial community composition and species absolute abundance to environmental factors under three fertilization treatments[chemical fertilizer(NPK),organic fertilizer replacing 30%of chemical fertilizer(30M,estimated in terms of pure nitrogen,same below),and organic fertilizer replacing 60%of chemical fertilizer(60M)]for two consecutive years.Furthermore,the changes of bacterial metabolic functions of different fertilization treatments were predicted by PICRUSt2.The results showed that replacing chemical fertilizer with organic fertilizer at different proportions significantly increased the total nitrogen(TN),total potassium(TK),hydrolyzable nitrogen(HN),soil organic carbon(SOC),and significantly decreased the soil bulk density(SBD).Moreover,60M demonstrated better performance than 30M.Different fertilization treatments did not cause significant difference in soil bacterial richness index(Chao1)or diversity index(Shannon)but significantly affected bacterial community composition and species abundance.Particularly,60M significantly increased the abundance of 227 species,and it increased the total bacterial abundance by 25.30%and 56.58%compared with NPK and 30M,respectively.Redundancy analysis and Spearman correlation analysis revealed that SOC,TN,and AK were the key factors for shaping specific bacterial community structures under different fertilization treatments.The 60M treatment significantly increased the abundance of bacterial species involved in xenobiotic biodegradation and metabolism,amino acid metabolism,and lipid metabolism,thus improving the metabolic functions of soil microorganisms.
基金Supported by the Special Study on Mineral Resources Planning in Changchun City(No.JM-2020-11-13594)Jilin Agricultural Geological Survey Project(No.12120105111208)。
文摘In order to identify the nutrient level and environmental quality of paddy fields in Wanchang area,and to provide scientific basis and technical support for planting rice in Wanchang area, the soil geochemicalsurvey was carried out, 30 samples were collected from paddy soil in Wanchang area, and 20 elements(indicators) were analyzed. The characterization of the elemental content of soils in the study area was carriedout, and the geochemical level for soil nutrients, the geochemical level for the soil environment, and thecomprehensive geochemical level of soil quality were evaluated. The results showed that the average valuesof K content and pH of the soil in the study area were smaller than the background values of Jilin Province,and the average values of 18 elements including N, P, Ca, S, Pb, Zn etc. were bigger than the backgroundvalues of Jilin Province. The results of the evaluation of soil single element nutrient in the study area showedthat the available state nutrient levels of Mn, Zn, Cu, and K increased compared with the total amounts ofnutrients level, with Cu increasing the most;the available state nutrient level of N, P, B, and Mo decreasedcompared with the total amounts of nutrients level, with Mo decreasing the most. The comprehensive levelof soil nutrients geochemistry in paddy fields was mainly Level III (medium), accounting for 53.33%, andthe low abundance level was caused by the lack of P element;the comprehensive level of soil environmentalgeochemistry was mainly Level I (clean), accounting for 96.67%, with only slight pollution caused byCd. The comprehensive geochemical level of soil quality was mainly Level II, accounting for 66.67%.Suggestions were put forward for the rational utilization of soil resources in paddy fields in the study area.
基金supported by the National Natural Science Foundation of China(32372118 and 32188102)the Qian Qian Academician Workstation,China+3 种基金the Specific Research Fund of the Innovation Platform for Academicians of Hainan Province,China(YSPTZX202303)the Nanfan Special Project,Chinese Academy of Agricultural Sciences(ZDXM2315)the Chinese Academy of Agricultural Sciences Talent Plan-Outstanding Young Talentthe Zhejiang Province’s High-level Talent Special Support Plan-Young Talent,China。
文摘In natural ecosystems,the timely abscission of seeds in wild plants is a crucial adaptive trait that contributes to reproductive success,population renewal,and colony expansion(Thurber et al.2010).In contrast,the tendency for high seed shattering in domesticated crops,such as rice,not only reduces paddy yield but also complicates mechanized harvesting.
