Identification of the most appropriate chemically extractable pool for evaluating Cd and Pb availability remains elusive,hindering accurate assessment on environmental risks and effectiveness of remediation strategies...Identification of the most appropriate chemically extractable pool for evaluating Cd and Pb availability remains elusive,hindering accurate assessment on environmental risks and effectiveness of remediation strategies.This study evaluated the feasibility of European Community Bureau of Reference(BCR)sequential extraction,Ca(NO_(3))_(2)extraction,and water extraction on assessing Cd and Pb availability in agricultural soil amended with slaked lime,magnesium hydroxide,corn stover biochar,and calcium dihydrogen phosphate.Moreover,the enriched isotope tracing technique(^(112)Cd and^(206)Pb)was employed to evaluate the aging process of newly introduced Cd and Pbwithin 56 days’incubation.Results demonstrated that extractable pools by BCR and Ca(NO_(3))_(2)extraction were little impacted by amendments and showed little correlation with soil pH.This is notable because soil pH is closely linked to metal availability,indicating these extraction methods may not adequately reflect metal availability.Conversely,water-soluble concentrations of Cd and Pb were markedly influenced by amendments and exhibited strong correlations with pH(Pearson’s r:-0.908 to-0.825,P<0.001),suggesting water extraction as a more sensitive approach.Furthermore,newly introduced metals underwent a more evident aging process as demonstrated by acid-soluble and water-soluble pools.Additionally,water-soluble concentrations of essential metals were impacted by soil amendments,raising caution on their potential effects on plant growth.These findings suggest water extraction as a promising and attractive method to evaluate Cd and Pb availability,which will help provide assessment guidance for environmental risks caused by heavy metals and develop efficient remediation strategies.展开更多
Organic material combined with inorganic fertilizer has been shown to greatly improve crop yield and maintain soil fertility globally. However, it remains unclear if crop yield and soil fertility can be sustained in t...Organic material combined with inorganic fertilizer has been shown to greatly improve crop yield and maintain soil fertility globally. However, it remains unclear if crop yield and soil fertility can be sustained in the long term under the combined application of organic and inorganic fertilizers. Three long-term field trials were conducted to investigate the effects of organic amendments on the grain sustainable yield index(SYI), soil fertility index(SFI)and nutrient balance in maize–wheat cropping systems of central and southern China during 1991–2019. Five treatments were included in the trials: 1) no fertilization(control);2) balanced mineral fertilization(NPK);3) NPK plus manure(NPKM);4) high dose of NPK plus manure(1.5NPKM);and 5) NPK plus crop straw(NPKS). Over time, the grain yields of wheat and maize showed an increasing trend in all four fertilization treatments at the Yangling(YL) and Zhengzhou(ZZ) locations, while they declined at Qiyang(QY). The grain yield in the NPKM and 1.5NPKM treatments gradually exceeded that of the NPK and NPKS treatments at the QY site. The largest SYI was recorded in the NPKM treatment across the three sites, suggesting that inorganic fertilizer combined with manure can effectively improve crop yield sustainability. Higher SYI values were recorded at the YL and ZZ sites than at the QY site, possibly because the soil was more acid at QY. The key factors affecting grain yield were soil available phosphorus(AP) and available potassium(AK) at the YL and ZZ sites, and pH and AP at the QY site.All fertilization treatments resulted in soil N and P surpluses at the three sites, but soil K surpluses were recorded only at the QY site. The SFI was greater in the 1.5NPKM, NPKM and NPKS treatments than in the NPK treatment by 13.3–40.0 and 16.4–63.6% at the YL and ZZ sites, respectively, and was significantly higher in the NPKM and 1.5NPKM treatments than in the NPK and NPKS treatments at the QY site. A significant, positive linear relationship was found between SFI and crop yield, and SYI and nutrient balance, indicating that grain yield and its sustainability significantly increased with increasing soil fertility. The apparent N, P and K balances positively affected SFI.This study suggests that the appropriate amount of manure mixed with mineral NPK fertilizer is beneficial to the development of sustainable agriculture, which effectively increases the crop yield and yield sustainability by improving soil fertility.展开更多
Despite the promising outcomes observed in individual applications of biochar and polyvinyl alcohol(PVA)in soil,the impact of their combined usage remains inadequately understood.This study systematically explores the...Despite the promising outcomes observed in individual applications of biochar and polyvinyl alcohol(PVA)in soil,the impact of their combined usage remains inadequately understood.This study systematically explores the effects of concurrent biochar and PVA application on key soil parameters,including pH,water-holding capacity(WHC),and dynamic moisture content(MC),and the photosynthetic resilience and growth of the cyanobacterium Microcoleus vaginatus in a desert soil.Biochars,generated at different pyrolysis temperatures(300-600℃),were applied to the soil at varying rates(1%-6%),while PVA was introduced at a mass percentage of 0.05%.The photosynthetic resilience and biomass accumulation of M.vaginatus in different treatments were examined every 7 d during the 28-d exposure to dry conditions after 60-d water supply.The combined application of biochar and PVA resulted in a reduction of soil pH,coupled with significant improvements in WHC and dynamic MC.Moreover,this combined approach exhibited superior effects on the photosynthetic resilience and crust thickness(0.9-3.5 mm)of M.vaginatus compared to the application of biochar and PVA in isolation.Incremental increase in biochar application rate from 0% to 6% demonstrated a notable enhancement in the chlorophyll a content of M.vaginatus.Cyanobacterial crust thickness and exopolysaccharide content exhibited positive correlations with biochar application rate.Thus,combined application of biochar and PVA is cost-effective for enhancing soil properties and cyanobacterial biomass,which is of significance for combating desertification.展开更多
Biochar has emerged as a promising tool for enhancing vineyard sustainability by improving soil properties and mitigating climate change impacts.This review highlights key findings on biochar’s role in viticulture,fo...Biochar has emerged as a promising tool for enhancing vineyard sustainability by improving soil properties and mitigating climate change impacts.This review highlights key findings on biochar’s role in viticulture,focusing on its effects on soil fertility,water retention,and plant physiology.Field and pot studies demonstrate that biochar amendments enhance soil structure,increase cation exchange capacity(CEC),and promote water availability,leading to improved drought resistance in grapevines.However,the impacts on grape yield,physiology,and quality remain inconclusive,with some studies reporting benefits while others show neutral effects.Future research should focus on optimizing biochar application rates,understanding its interactions with soil microbiota,and assessing long-term impacts on grape production and wine quality.Additionally,addressing potential risks,such as heavy metal contamination and changes in microbial communities,is crucial for its safe and effective use.This review aims to supply a comprehensive assessment of our knowledge about the incidence and consequences of biochar on soil,including its potential use in soil remediation and concerns regarding its possible negative impacts,with a focus on its effects on vine physiology and grape production.展开更多
Traditional studies of microbial succession under iron-carbon composite(Fe-C)amendment application have focused on the entire microbial community,with limited attention to the responses and ecological roles of abundan...Traditional studies of microbial succession under iron-carbon composite(Fe-C)amendment application have focused on the entire microbial community,with limited attention to the responses and ecological roles of abundant or rare taxa.Herein,a 90-day microcosm incubation was conducted to investigate the effects of three Fe-C amendments,including Fe_(3)O_(4)-modified biochar(FeC-B),ferrihydrite-natural humic acid(FeC-N),and ferrihydrite-synthetic humic-like acid(FeC-S),on distribution patterns,assembly processes,and ecological functions of both abundant and rare subcommunities.Our results showed that Fe-C amendments significantly affected theα-diversity of rare taxa,particularly under FeC-B treatment,with minimal impact on abundant taxa.Fe-C amendments also reshaped the community structures of both groups.Rare taxa,representing 63.9%of Operational Taxonomic Unit(OTU)richness but only 1.6%of total abundance,played a key role in community diversity and were more susceptible to Fe-C amendments.Certain rare taxa transitioned to abundant status,demonstrating their potential as a microbial seed bank.Abundant taxa were positioned more centrally within the networks,and Fe-C applications promoted cooperative interactions between abundant and rare species.Deterministic processes dominated the assembly of the rare subcommunity,while stochastic processes primarily influenced the abundant bacterial community.Fe-C amendments reduced community differentiation among rare taxa while increasing variability among abundant groups.Functional diversity of rare groups surpassed that of abundant groups,with notable enhancement in nitrogen cycling-related genes under Fe-C treatments.This study highlights the complementary roles of abundant and rare taxa in soil remediation,providing insights for optimizing remediation strategies.展开更多
Rubble deposits with a high concentration of rock debris were created after the powerful earthquakes in Jiuzhaigou.Because of the restricted soil resources,water leaks,and nutrient deficits,these deposits pose serious...Rubble deposits with a high concentration of rock debris were created after the powerful earthquakes in Jiuzhaigou.Because of the restricted soil resources,water leaks,and nutrient deficits,these deposits pose serious obstacles for vegetation regeneration.The purpose of this study was to investigate the main mechanisms controlling soil water retention and evaluate the effects of different amendments on the hydraulic characteristics and water-holding capacity of collapsed rubble soils.Finegrained soil,forest humus,crushed straw,and organic components that retain water were added to the altered soils to study the pore structure images and soil-water characteristic curves.Comparing understory humus to other supplements,the results showed a considerable increase in the soil's saturated and wilting water content.The saturated water content and wilting water content rose by 17.9%and 4.3%,respectively,when the percentage of understory soil reached 30%.Additionally,the enhanced soil's microporosity and total pore volume increased by 45.33%and 11.27%,respectively,according to nuclear magnetic imaging.It was shown that while clay particles and organic matter improved the soil's ability to adsorb water,they also increased the soil's total capacity to store water.Fine particulate matter did this by decreasing macropores and increasing capillary pores.These results offer an essential starting point for creating strategies for soil repair that would encourage the restoration of plants on slopes that have been damaged.展开更多
Organic amendments(OM)can profoundly affect soil nitrous oxide(N_(2)O)emissions via changing nitrogen(N)cycles.However,mechanistic insights into how nitrification inhibitors modulate the responses of soil N_(2)O emiss...Organic amendments(OM)can profoundly affect soil nitrous oxide(N_(2)O)emissions via changing nitrogen(N)cycles.However,mechanistic insights into how nitrification inhibitors modulate the responses of soil N_(2)O emissions to successive applications of OM are currently insufficient.In this study,we performed a laboratory experiment to examine N_(2)O emissions from a tropical vegetable soil subjected to six years of chemical fertilization(CF)and chemical fertilization combined with manure application(CFM)and evaluate the mitigation effectiveness of nitrification inhibitor dicyandiamide(DCD)under each management regime.Isotopocule mapping showed that bacterial nitrification and/or fungal denitrification accounted for 77.4%–88.5%of total N_(2)O production across treatments during the emission peak.The cumulative N_(2)O emissions from the CFM-treated soil were nearly 8-fold of those from the CF-treated soil.The CFM treatment stimulated N_(2)O production from bacterial nitrification and denitrification by increasing the abundance of genes linked to nitrifiers(ammonia-oxidizing bacterial(AOB)amoA and total comammox amoA)and denitrifiers(nirK,nirS,and qnorB),respectively.Importantly,DCD decreased cumulative N_(2)O emissions by an average of 73.3%,with better mitigation performance observed in the CFM-treated soil than in the CF-treated soil due to stronger inhibited nitrification and increased abundance of the nosZ gene,and altered bacterial community composition.The 16S rRNA sequencing further revealed that adding DCD to the CFM-treated soil resulted in declines in the abundances of bacterial phylum Actinobacteria and Chloroflexi that positively affected N_(2)O emissions;the opposite pattern prevailed for Gemmatimonadetes that negatively affected N_(2)O emissions.This study highlights the potential of manure application,when coupled with nitrification inhibitors,to achieve the dual goals of enhancing soil fertility and reducing environmental risk associated with N_(2)O emissions in tropical agricultural soils.展开更多
Water scarcity and soil salinization pose significant challenges to agriculture in the West Liaohe Plain,eastern Inner Mongolia,China.Shallow-buried drip irrigation can improve soil water use efficiency to alleviate w...Water scarcity and soil salinization pose significant challenges to agriculture in the West Liaohe Plain,eastern Inner Mongolia,China.Shallow-buried drip irrigation can improve soil water use efficiency to alleviate water shortage in agriculture and the application of lignite humic acid reduces the adverse effects of soil salinization.However,further research is needed to investigate the effects of different application rates of lignite humic acid and humic acid-based combined amendment on soil physicochemical properties,nutrient contents,and crop yield in saline-sodic farmlands under shallow-buried drip irrigation.A two-year field experiment was conducted with control without any amendment(CK),three treatments amended with 3 t/ha(H1),6 t/ha(H2),and 12 t/ha(H3)lignite humic acid,and three application rates with 15 t/ha(T1),22.5 t/ha(T2),and 30 t/ha(T3)lignite humic acid-based combined amendment in 2021 and2022.The results showed that H3 reduced soil bulk density,p H,electrical conductivity,and total alkalinity,while increasing the contents of soil organic matter,total nitrogen,and available potassium in the two-year experiment.Moreover,the maize yield in H3 increased by an average of 35.5%.T2 decreased soil bulk density,p H,total alkalinity,and increased maize yield by 16.2%,compared to the first year.These results suggest that T2 consistently improved both soil quality and crop yield.Correlation analyses showed that lignite humic acid and its complexes promote maize growth and increase yield by increasing soil organic matter and total nitrogen while reducing soil salinity and total alkalinity.Based on the comprehensive analysis of the field data and the results of the comprehensive evaluation of soil quality,it was determined that the appropriate improvement measures for saline-sodic farmlands under shallow-buried drip irrigation are the application of 12 t/ha of lignite humic acid and 22.5 t/ha of lignite humic acid-based combined amendment.This study demonstrates the effectiveness of lignite humic acid and its combined amendment in mitigating the constraints of saline-sodic farmlands and enhancing crop yields,providing a sustainable solution for improving saline-sodic farmlands in the West Liaohe Plain.展开更多
An amendment to the Electoral Law of the National People’s Congress and Local People’s Congresses of the People’s Republic of China providing equal legislative representation to rural and urban people was ratified ...An amendment to the Electoral Law of the National People’s Congress and Local People’s Congresses of the People’s Republic of China providing equal legislative representation to rural and urban people was ratified at the closing meeting of the Third Session of the 1 1th展开更多
Population growth and growing demand for livestock products produce large amounts of manure,which can be harnessed to maintain soil sustainability and crop productivity.However,the impacts of excessive manure applicat...Population growth and growing demand for livestock products produce large amounts of manure,which can be harnessed to maintain soil sustainability and crop productivity.However,the impacts of excessive manure application on crop yields,nitrogen(N)-cycling processes and microorganisms remain unknown.Here,we explored the effects of 20-year of excessive rates(18 and 27 Mg ha^(–1)yr^(–1))of pig manure application on peanut crop yields,soil nutrient contents,N-cycling processes and the abundance of N-cycling microorganisms in an acidic Ultisol in summer and winter,compared with none and a regular rate(9 Mg ha^(–1)yr^(–1))of pig manure application.Long-term excessive pig manure application,especially at the high-rate,significantly increased soil nutrient contents,the abundance of N-cycling functional genes,potential nitrification and denitrification activity,while it had a weaker effect on peanut yield and plant biomass.Compared with manure application,seasonality had a much weaker effect on N-cycling gene abundance.Random forest analysis showed that available phosphorus(AP)content was the primary predictor for N-cycling gene abundance,with significant and positive associations with all tested N-cycling genes.Our study clearly illustrated that excessive manure application would increase N-cycling gene abundance and potential N loss with relatively weak promotion of crop yields,providing significant implications for sustainable agriculture in the acidic Ultisols.展开更多
The digestibility of cadmium(Cd)in brown rice is directly related to amino acid metabolism in rice and human health.In our field study,three kinds of alkaline calcium-rich soil inorganic amendments(SIAs)at three dosag...The digestibility of cadmium(Cd)in brown rice is directly related to amino acid metabolism in rice and human health.In our field study,three kinds of alkaline calcium-rich soil inorganic amendments(SIAs)at three dosages were applied to produce safe rice and improve the quality of rice in Cd-contaminated paddy.With the increased application of SIA,Cd content in iron plaque on rice root significantly increased,the transfer of Cd from rice root to grain significantly decreased,and then Cd content in brown rice decreased synchronously.The vitro digestibility of Cd in brown rice was estimated by a physiologically based extraction test.Results showed that more than 70%of Cd in brown rice could be digested by simulated gastrointestinal juice.Based on the total and digestible Cd contents in brown rice to evaluate the health risk,the application of 2.25 ton SIA/ha could produce safe rice in acidic slightly Cd-contaminated paddy soils.The amino acids(AAs)in brown rice were determined by high-performance liquid chromatography.The contents of 5 key AAs(KAAs)that actively respond to environmental changes increased significantly with the increased application of SIA.The structural equation model indicated that KAAs could be affected by the Cd translocation capacity from rice root to grain,and consequently altered the ratio of indigestible Cd in brown rice.The formation of indigestible KAAs-Cd complexes by combining KAAs(phenylalanine,leucine,histidine,glutamine,and asparagine)with Cd in brown rice could be considered a potential mechanism for reducing the digestibility of Cd.展开更多
Chemical immobilization,as a cost-effective and environmentally friendly technique,has been widely researched in the remediation of cadmium(Cd)-contaminated soil.The key is to find appropriate amendments and optimize ...Chemical immobilization,as a cost-effective and environmentally friendly technique,has been widely researched in the remediation of cadmium(Cd)-contaminated soil.The key is to find appropriate amendments and optimize their use.In this study,the effects of the application of an inorganic material(phosphorus slag(PS))and organic materials(biochar(BC)and beer lees(BL)),individually or combinedly on the immobilization of Cd in contaminated soil and subsequent bioaccumulation in Chinese cabbage were investigated.The results showed that PS and PS+BL were more effective in decreasing exchangeable Cd(EX-Cd)than other treatments,decreased by 91.2%in the PS treatment and by 64.0%in the PS+BL treatment.However,the soil enzyme activity and soil microbial activity decreased in the treatment with PS alone.In contrast,the combination use of PS and BL could increase soil enzyme activity,soil microbial activity,and functional diversity,and decrease EX-Cd as well.Moreover,the PS+BL treatment reduced the accumulation of Cd in Chinese cabbage most effectively,81.5%in roots and 72.5%in shoots.This treatment could also increase the aboveground height and chlorophyll content of Chinese cabbage while reducing the content of malondialdehyde(MDA).Thus,the PS+BL treatment is highly recommended for Cd immobilization,as it can improve soil quality and reduce Cd accumulation in Chinese cabbage at the same time and hence promote plant growth.展开更多
Public urban greenery greatly contributes to the residential and tourist value of cities in the Gulf Region,but due to the hyper-arid climatic conditions,the cost of irrigation and plant maintenance is very high.Exist...Public urban greenery greatly contributes to the residential and tourist value of cities in the Gulf Region,but due to the hyper-arid climatic conditions,the cost of irrigation and plant maintenance is very high.Existing strategies to reduce the monetary and ecological costs involve the cultivation of native xerophytic plantations,and/or the use of soil improvers to increase water-and nutrient-holding capacity of the sandy soils.Various soil improvers based on mineral,organic,or synthetic materials have entered the United Arab Emirates(UAE)market in recent years,but there is considerable uncertainty about how they should best be used in combination with ornamental plant stands involving xerophytic native plants.The present study investigated the effect of soil amendment and deep pipe irrigation on perennial ornamental plant stands involving native plants(Tephrosia appolinea(Gel.)Link in combination with Aerva javanica(Burm.f.)Juss.ex Schult.)and native-exotic plants(T.appolinea in combination with Ruelia simplex C.Wright)either or not topsoil and subsoil amendment with bentonite and hydrophobic sand under the irrigation water supply of less than 50%of reference evapotranspiration(ET0).After one year of cultivation,T.appolinea and A.javanica(native vs.native)produced high biomass and exhibited high water use efficiency(WUE)as compared with T.appolinea and R.simplex(native vs.exotic)combination given that no significant differences were found under the soil amendment treatments.All stands thrived under irrigation water supply far below what is usually supplied to exotic ornamental stands in public parks of the Al Ain City,the UAE.However,subsoil amendment in combination with deep pipe irrigation reduced the occurrence of weeds and increased the overall plant rooting depth.Our results suggest that subsoil amendment and irrigation up to 60-80 cm depth can potentially control ephemeral weed infestation,which is a great challenge in various plant production systems of the Gulf Region.The results of the present study suggest that the impact of soil amendment on the WUE of exotic plants is marginal and might not be economically justified.Replacing exotic with native ornamental plant species seems to have a far greater water-saving potential than the amendment of the soil,while weeds can be suppressed in the absence of topsoil moisture.展开更多
Excess available K and Fe in Fe ore tailings with organic matter amendment and water-deficiencies may restrain plant colonization and growth,which hinders the formation of eco-engineered soil from these tailings for s...Excess available K and Fe in Fe ore tailings with organic matter amendment and water-deficiencies may restrain plant colonization and growth,which hinders the formation of eco-engineered soil from these tailings for sustainable and cost-effective mine site rehabilitation.Arbuscular mycorrhizal(AM)fungi are widely demonstrated to assist plant growth under various unfavorable environments.However,it is still unclear whether AM symbiosis in tailings amended with different types of plant biomass and under different water conditions could overcome the surplus K and Fe stress for plants in Fe ore tailings,and if so,by what mechanisms.Here,host plants(Sorghum sp.Hybrid cv.Silk),either colonized or noncolonized by the AM fungi(Glomus spp.),were cultivated in lucerne hay(LH,C:N ratio of 18)-or sugarcane mulch(SM,C:N ratio of 78)-amended Fe ore tailings under well-watered(55%water-holding capacity(WHC)of tailings)or water-deficient(30%WHC of tailings)conditions.Root mycorrhizal colonization,plant growth,and mineral elemental uptake and partitioning were examined.Results indicated that AM fungal colonization improved plant growth in tailings amended with plant biomass under water-deficient conditions.Arbuscular mycorrhizal fungal colonization enhanced plant mineral element uptake,especially P,both in the LH-and SM-amended tailings regardless of water condition.Additionally,AM symbiosis development restrained the translocation of excess elements(i.e.,K and Fe)from plant roots to shoots,thereby relieving their phytotoxicity.The AM fungal roles in P uptake and excess elemental partitioning were greater in LH-amended tailings than in SM-amended tailings.Water deficiency weakened AM fungal colonization and functions in terms of mineral element uptake and partitioning.These findings highlighted the vital role AM fungi played in regulating plant growth and nutrition status in Fe ore tailings technosol,providing an important basis for involvement of AM fungi in the eco-engineered pedogenesis of Fe ore tailings.展开更多
In agricultural soils, phosphorus is often limited, leading farmers to employ artificial supplementation through both inorganic and organic fertilization methods due to its restricted availability. Soil fertilization ...In agricultural soils, phosphorus is often limited, leading farmers to employ artificial supplementation through both inorganic and organic fertilization methods due to its restricted availability. Soil fertilization has the potential to augment both the abundance and diversity of bacterial communities. Our study aimed to assess the effects of phosphate amendments, derived from natural phosphate rock, and chemical fertilizers (TSP, NPK), on the density and diversity of bacterial communities within the study plots. We developed and applied eight phosphate amendments during the initial cultivation cycle. Soil samples were collected post 1st and 2nd cultivation cycles, and the quantification of both total and cultivable phosphate-solubilizing bacteria (PSB) was conducted. Additionally, we analyzed bacterial community structure, α-diversity (Shannon Diversity Index, Evenness Index, Chao1 Index). The combination of natural phosphate rock (PR) and chemical fertilizers (TSP, NPK) significantly increased (p 7 bacteria/g dry soil) and phosphate-solubilizing bacteria (0.01 to 6.8 × 107 PSB/g dry soil) in comparison to unamended control soils. The diversity of bacterial phyla (Firmicutes, Actinobacteria, Proteobacteria, Halobacterota, Chloroflexia) observed under each treatment remained consistent regardless of the nature of the phosphate amendment applied. However, changes in the abundance of the bacterial phyla populations were observed as a function of the nature of the phosphate amendment or chemical fertilizer. It appears that the addition of excessive natural phosphate rock does not alter the number and the diversity of soil microorganisms population despite successive cultivation cycles. However, the addition of excessive chemical fertilizer reduces soil microorganisms density and structure after the 2nd cultivation cycle.展开更多
Ploughing and fertilization practices in rice-wheat system have deteriorated the soil carbon (C) pools. Conservation agriculture (CA) based management approaches have proven to enhance C sequestration and reverse the ...Ploughing and fertilization practices in rice-wheat system have deteriorated the soil carbon (C) pools. Conservation agriculture (CA) based management approaches have proven to enhance C sequestration and reverse the loss of soil-organic-carbon (SOC), which further enhances soil fertility. Different fractions of SOC pools react to the alterations in management practices and indicate changes in SOC dynamics as compared to total C in the soil. Higher SOC levels in soil have been observed in case of reduced/no-till (NT) practices than conventional tillage (CT). However, between CT and zero tillage/NT, total SOC stocks diminished with an increase in soil depth, which demonstrated that the benefits of SOC are more pronounced in the topsoil under NT. Soil aggregation provides physical protection to C associated with different-sized particles, thus, the improvement in soil aggregation through CA is an effective way to mitigate soil C loss. Along with less soil disturbance, residual management, suitable crop rotation, rational application of manures and fertilizers, and integrated nutrient management have been found to be effective in not only improving soil C stock but also enhancing the soil health and productivity. Thus, CA can be considered as a potential method in the build-up of SOC of soil in rice-wheat system.展开更多
Global mean surface air temperature is expected to increase 1.1˚C - 6.4˚C by the end of 21st century which may affect rice productivity and methane emissions in the future climate. This experiment was conducted to inv...Global mean surface air temperature is expected to increase 1.1˚C - 6.4˚C by the end of 21st century which may affect rice productivity and methane emissions in the future climate. This experiment was conducted to investigate the response of rice cultivars to elevated air temperature (+1.5˚C higher than ambient) and soil amendments in regards to rice yield, yield scaled methane emissions and global warming potentials. The experimental findings revealed that replacement of inorganic fertilizers (20% - 40% of recommended NPKS) with Vermicompost, Azolla biofertilizer, enriched sugarcane pressmud, rice husk biochar and silicate fertilization increased rice yield 13.0% - 23.0%, and 11.0% - 19.0% during wet aman and dry boro season, respectively. However, seasonal cumulative CH4 fluxes were decreased by 9.0% - 25.0% and 5.0% - 19.0% during rainfed wet aman and irrigated dry boro rice cultivation, respectively with selected soil amendments. The maximum reduction in seasonal cumulative CH4 flux (19.0% - 25.0%) was recorded with silicate fertilization and azolla biofertilizer amendments (9.0% - 13.0%), whereas maximum grain yield increment 10.0 % - 14.0% was found with Vermicompost and Sugarcane pressmud amendments compared to chemical fertilization (100% NPKS) treated soils at ambient air temperature. However, rice grain yield decreased drastically 43.0% - 50.0% at elevated air temperature (3˚C higher than ambient air temperature), eventhough accelerated the total cumulative CH4 flux as well as GWPs in all treatments. Maximum seasonal mean GWPs were calculated at 391.0 kg CO2 eq·ha−1 in rice husk biochar followed by sugarcane pressmud (mean GWP 387.0 kg CO2 eq·ha−1), while least GWPs were calculated at 285 - 305 kg CO2 eq·ha−1 with silicate fertilizer and Azolla biofertilizer amendments. Rice cultivar BRRI dhan 87 revealed comparatively higher seasonal cumulative CH4 fluxes, yield scaled CH4 flux and GWPs than BRRI dhan 71 during wet aman rice growing season;while BRRI dhan 89 showed higher cumulative CH4 flux and GWPs than BINA dhan 10 during irrigated boro rice cultivation. Conclusively, inorganic fertilizers may be partially (20% - 40% of the recommended NPKS) replaced with Vermicompost, azolla biofertilizer, silicate fertilizer and enriched sugarcane pressmud compost for sustainable rice production and decreasing GWPs under elevated air temperature condition.展开更多
Soil contamination by hydrocarbons poses numerous environmental, health and agricultural problems. The degradation of these pollutants can occur naturally but very slowly. It is therefore generally necessary to stimul...Soil contamination by hydrocarbons poses numerous environmental, health and agricultural problems. The degradation of these pollutants can occur naturally but very slowly. It is therefore generally necessary to stimulate this degradation by different means. Thus, this study aimed to improve the bio-degradation of diesel and crude oil in a Ghanaian soil by biostimulation. For this, the sampled soil was characterized by standard methods and contaminated with diesel and crude oil at a proportion of 1% (w/w). Then, contaminated soil samples were supplemented with biochar-compost, poultry manure or cow dung at the proportion of 10% (w/w). Periodically, fractions of these samples were taken to evaluate the density of hydrocarbon utilizing bacteria (HUB) and the residual quantities of diesel or crude oil. The characteristics of the soil used show the need for supplementation for better degradation of hydrocarbons. The results of the study show that supplementing the soil with organic substrates increases HUB loads in soils contaminated by diesel and crude oil. They also show that the residual quantities of diesel and crude oil are generally significantly lower in supplemented soils (p = 0.048 and p < 0.0001 respectively). In addition, the study shows that degradation was generally greater in soils contaminated by diesel compared to those contaminated by crude oil, especially at the end of the study.展开更多
In arid and semiarid regions such as Niger, irrigated agriculture leads to soil salinization, particularly through irrigation water salts, and has adverse effects on crop production such as vegetable crops including o...In arid and semiarid regions such as Niger, irrigated agriculture leads to soil salinization, particularly through irrigation water salts, and has adverse effects on crop production such as vegetable crops including onion. The main objective of this study, conducted in the experimental site of Djibo Hamani University of Tahoua in Niger, was to evaluate the effects of organic fertilizer on the growth and yield of onion crops irrigated with saline water. The experiment was performed in split-plot design to test tree type of fertilizer (chemical fertilizer, compost and millet glumes) and four (04) levels of irrigation water salinity in electrical conductivity values (ECw) (S0 = 0.28 dS/m as control, S1 = 2 dS/m, S2 = 4 dS/m and S3 = 6 dS/m). The growth parameters and bulb yield were evaluated during 4 months of onion cropping season. The results showed that the use of irrigation saline water significantly decreased the growth and bulb yield of onion crops. The yield in onion bulbs is 1.55 to 3.94 times higher with control (0.28 dS/m) than that with high saline water (ECw = 6 dS/m). Compared to control in irrigation water, the reduction in fresh onion bulb yield was 38.8, 52.6 and 63.5% respectively for ECw of 2, 4 and 6 dS/m. Furthermore, the application of organic fertilizers, particularly compost, improves salt-tolerance of onion crops in order to promote growth and bulb yield. Indeed, when irrigating onion crops with saline water (ECw of 2, 4 and 6 dS/m), the onion bulb yield is significantly higher under compost than under chemical fertilizer and glumes. At high irrigation saline water (ECw = 6 dS/m), the yield in onion bulbs is 1.9 and 2.1 times higher under compost than that under chemical fertilizer and glumes respectively. Thus, the compost is the promising organic amendment in a semiarid region of Tahoua in Niger to reduce the adverse effects of irrigation saline water on onion crop production.展开更多
基金supported by the National Natural Science Foundation of Shandong(No.ZR2020ZD20)the National Natural Science Foundation of China(No.22193051)+1 种基金the National Young Top-Notch Talents(No.W03070030)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.Y202011).
文摘Identification of the most appropriate chemically extractable pool for evaluating Cd and Pb availability remains elusive,hindering accurate assessment on environmental risks and effectiveness of remediation strategies.This study evaluated the feasibility of European Community Bureau of Reference(BCR)sequential extraction,Ca(NO_(3))_(2)extraction,and water extraction on assessing Cd and Pb availability in agricultural soil amended with slaked lime,magnesium hydroxide,corn stover biochar,and calcium dihydrogen phosphate.Moreover,the enriched isotope tracing technique(^(112)Cd and^(206)Pb)was employed to evaluate the aging process of newly introduced Cd and Pbwithin 56 days’incubation.Results demonstrated that extractable pools by BCR and Ca(NO_(3))_(2)extraction were little impacted by amendments and showed little correlation with soil pH.This is notable because soil pH is closely linked to metal availability,indicating these extraction methods may not adequately reflect metal availability.Conversely,water-soluble concentrations of Cd and Pb were markedly influenced by amendments and exhibited strong correlations with pH(Pearson’s r:-0.908 to-0.825,P<0.001),suggesting water extraction as a more sensitive approach.Furthermore,newly introduced metals underwent a more evident aging process as demonstrated by acid-soluble and water-soluble pools.Additionally,water-soluble concentrations of essential metals were impacted by soil amendments,raising caution on their potential effects on plant growth.These findings suggest water extraction as a promising and attractive method to evaluate Cd and Pb availability,which will help provide assessment guidance for environmental risks caused by heavy metals and develop efficient remediation strategies.
基金supported by the National Natural Science Foundation of China(42177341)the Natural Science Basic Research Program of Shanxi,China(202203021222138).
文摘Organic material combined with inorganic fertilizer has been shown to greatly improve crop yield and maintain soil fertility globally. However, it remains unclear if crop yield and soil fertility can be sustained in the long term under the combined application of organic and inorganic fertilizers. Three long-term field trials were conducted to investigate the effects of organic amendments on the grain sustainable yield index(SYI), soil fertility index(SFI)and nutrient balance in maize–wheat cropping systems of central and southern China during 1991–2019. Five treatments were included in the trials: 1) no fertilization(control);2) balanced mineral fertilization(NPK);3) NPK plus manure(NPKM);4) high dose of NPK plus manure(1.5NPKM);and 5) NPK plus crop straw(NPKS). Over time, the grain yields of wheat and maize showed an increasing trend in all four fertilization treatments at the Yangling(YL) and Zhengzhou(ZZ) locations, while they declined at Qiyang(QY). The grain yield in the NPKM and 1.5NPKM treatments gradually exceeded that of the NPK and NPKS treatments at the QY site. The largest SYI was recorded in the NPKM treatment across the three sites, suggesting that inorganic fertilizer combined with manure can effectively improve crop yield sustainability. Higher SYI values were recorded at the YL and ZZ sites than at the QY site, possibly because the soil was more acid at QY. The key factors affecting grain yield were soil available phosphorus(AP) and available potassium(AK) at the YL and ZZ sites, and pH and AP at the QY site.All fertilization treatments resulted in soil N and P surpluses at the three sites, but soil K surpluses were recorded only at the QY site. The SFI was greater in the 1.5NPKM, NPKM and NPKS treatments than in the NPK treatment by 13.3–40.0 and 16.4–63.6% at the YL and ZZ sites, respectively, and was significantly higher in the NPKM and 1.5NPKM treatments than in the NPK and NPKS treatments at the QY site. A significant, positive linear relationship was found between SFI and crop yield, and SYI and nutrient balance, indicating that grain yield and its sustainability significantly increased with increasing soil fertility. The apparent N, P and K balances positively affected SFI.This study suggests that the appropriate amount of manure mixed with mineral NPK fertilizer is beneficial to the development of sustainable agriculture, which effectively increases the crop yield and yield sustainability by improving soil fertility.
基金the financial support from the National Natural Science Foundation of China(Nos.22378154 and 21975089)the Fundamental Research Funds for the Central Universities of China(No.2017KFKJFP002)。
文摘Despite the promising outcomes observed in individual applications of biochar and polyvinyl alcohol(PVA)in soil,the impact of their combined usage remains inadequately understood.This study systematically explores the effects of concurrent biochar and PVA application on key soil parameters,including pH,water-holding capacity(WHC),and dynamic moisture content(MC),and the photosynthetic resilience and growth of the cyanobacterium Microcoleus vaginatus in a desert soil.Biochars,generated at different pyrolysis temperatures(300-600℃),were applied to the soil at varying rates(1%-6%),while PVA was introduced at a mass percentage of 0.05%.The photosynthetic resilience and biomass accumulation of M.vaginatus in different treatments were examined every 7 d during the 28-d exposure to dry conditions after 60-d water supply.The combined application of biochar and PVA resulted in a reduction of soil pH,coupled with significant improvements in WHC and dynamic MC.Moreover,this combined approach exhibited superior effects on the photosynthetic resilience and crust thickness(0.9-3.5 mm)of M.vaginatus compared to the application of biochar and PVA in isolation.Incremental increase in biochar application rate from 0% to 6% demonstrated a notable enhancement in the chlorophyll a content of M.vaginatus.Cyanobacterial crust thickness and exopolysaccharide content exhibited positive correlations with biochar application rate.Thus,combined application of biochar and PVA is cost-effective for enhancing soil properties and cyanobacterial biomass,which is of significance for combating desertification.
文摘Biochar has emerged as a promising tool for enhancing vineyard sustainability by improving soil properties and mitigating climate change impacts.This review highlights key findings on biochar’s role in viticulture,focusing on its effects on soil fertility,water retention,and plant physiology.Field and pot studies demonstrate that biochar amendments enhance soil structure,increase cation exchange capacity(CEC),and promote water availability,leading to improved drought resistance in grapevines.However,the impacts on grape yield,physiology,and quality remain inconclusive,with some studies reporting benefits while others show neutral effects.Future research should focus on optimizing biochar application rates,understanding its interactions with soil microbiota,and assessing long-term impacts on grape production and wine quality.Additionally,addressing potential risks,such as heavy metal contamination and changes in microbial communities,is crucial for its safe and effective use.This review aims to supply a comprehensive assessment of our knowledge about the incidence and consequences of biochar on soil,including its potential use in soil remediation and concerns regarding its possible negative impacts,with a focus on its effects on vine physiology and grape production.
基金supported by the National Natural Science Foundation of China(No.42007128)the Fundamental Research Funds for the Central Universities(No.2024QNYL30)the Graduate Research and Practice Projects of Minzu University of China(No.SZKY2024034).
文摘Traditional studies of microbial succession under iron-carbon composite(Fe-C)amendment application have focused on the entire microbial community,with limited attention to the responses and ecological roles of abundant or rare taxa.Herein,a 90-day microcosm incubation was conducted to investigate the effects of three Fe-C amendments,including Fe_(3)O_(4)-modified biochar(FeC-B),ferrihydrite-natural humic acid(FeC-N),and ferrihydrite-synthetic humic-like acid(FeC-S),on distribution patterns,assembly processes,and ecological functions of both abundant and rare subcommunities.Our results showed that Fe-C amendments significantly affected theα-diversity of rare taxa,particularly under FeC-B treatment,with minimal impact on abundant taxa.Fe-C amendments also reshaped the community structures of both groups.Rare taxa,representing 63.9%of Operational Taxonomic Unit(OTU)richness but only 1.6%of total abundance,played a key role in community diversity and were more susceptible to Fe-C amendments.Certain rare taxa transitioned to abundant status,demonstrating their potential as a microbial seed bank.Abundant taxa were positioned more centrally within the networks,and Fe-C applications promoted cooperative interactions between abundant and rare species.Deterministic processes dominated the assembly of the rare subcommunity,while stochastic processes primarily influenced the abundant bacterial community.Fe-C amendments reduced community differentiation among rare taxa while increasing variability among abundant groups.Functional diversity of rare groups surpassed that of abundant groups,with notable enhancement in nitrogen cycling-related genes under Fe-C treatments.This study highlights the complementary roles of abundant and rare taxa in soil remediation,providing insights for optimizing remediation strategies.
基金jointly funded by the Sichuan Provincial Natural Science Foundation of China(Grant No.2023NSFSC0378)the Jiuzhaigou Lake Swamp and River Ecological Restoration Research Project(N5132112022000246)the Research base and Support provided by Jiuzhaigou Administration for this study。
文摘Rubble deposits with a high concentration of rock debris were created after the powerful earthquakes in Jiuzhaigou.Because of the restricted soil resources,water leaks,and nutrient deficits,these deposits pose serious obstacles for vegetation regeneration.The purpose of this study was to investigate the main mechanisms controlling soil water retention and evaluate the effects of different amendments on the hydraulic characteristics and water-holding capacity of collapsed rubble soils.Finegrained soil,forest humus,crushed straw,and organic components that retain water were added to the altered soils to study the pore structure images and soil-water characteristic curves.Comparing understory humus to other supplements,the results showed a considerable increase in the soil's saturated and wilting water content.The saturated water content and wilting water content rose by 17.9%and 4.3%,respectively,when the percentage of understory soil reached 30%.Additionally,the enhanced soil's microporosity and total pore volume increased by 45.33%and 11.27%,respectively,according to nuclear magnetic imaging.It was shown that while clay particles and organic matter improved the soil's ability to adsorb water,they also increased the soil's total capacity to store water.Fine particulate matter did this by decreasing macropores and increasing capillary pores.These results offer an essential starting point for creating strategies for soil repair that would encourage the restoration of plants on slopes that have been damaged.
基金supported by the National Natural Science Foundation of China(Nos.42007098 and 32001209)the Major Science and Technology Plan of Hainan Province,China(No.ZDKJ2021008)+1 种基金the Natural Science Foundation of Hainan Province,China(Nos.320RC687 and 421QN0915)the Central PublicInterest Scientific Institution Basal Research Fund for Chinese Academy of Tropical Agricultural Sciences(Nos.1630042025001,1630042025011,and 1630042025012)。
文摘Organic amendments(OM)can profoundly affect soil nitrous oxide(N_(2)O)emissions via changing nitrogen(N)cycles.However,mechanistic insights into how nitrification inhibitors modulate the responses of soil N_(2)O emissions to successive applications of OM are currently insufficient.In this study,we performed a laboratory experiment to examine N_(2)O emissions from a tropical vegetable soil subjected to six years of chemical fertilization(CF)and chemical fertilization combined with manure application(CFM)and evaluate the mitigation effectiveness of nitrification inhibitor dicyandiamide(DCD)under each management regime.Isotopocule mapping showed that bacterial nitrification and/or fungal denitrification accounted for 77.4%–88.5%of total N_(2)O production across treatments during the emission peak.The cumulative N_(2)O emissions from the CFM-treated soil were nearly 8-fold of those from the CF-treated soil.The CFM treatment stimulated N_(2)O production from bacterial nitrification and denitrification by increasing the abundance of genes linked to nitrifiers(ammonia-oxidizing bacterial(AOB)amoA and total comammox amoA)and denitrifiers(nirK,nirS,and qnorB),respectively.Importantly,DCD decreased cumulative N_(2)O emissions by an average of 73.3%,with better mitigation performance observed in the CFM-treated soil than in the CF-treated soil due to stronger inhibited nitrification and increased abundance of the nosZ gene,and altered bacterial community composition.The 16S rRNA sequencing further revealed that adding DCD to the CFM-treated soil resulted in declines in the abundances of bacterial phylum Actinobacteria and Chloroflexi that positively affected N_(2)O emissions;the opposite pattern prevailed for Gemmatimonadetes that negatively affected N_(2)O emissions.This study highlights the potential of manure application,when coupled with nitrification inhibitors,to achieve the dual goals of enhancing soil fertility and reducing environmental risk associated with N_(2)O emissions in tropical agricultural soils.
基金Under the auspices of the National Key Research and Development Program of China(No.2022YFD1500501)the Innovation Team Project of Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences(No.2023CXTD02)+2 种基金the National Natural Science Foundation of China(No.41971066)the Key Laboratory Foundation of Mollisols Agroecology(No.2020ZKHT-03)the High Tech Fund Project of S&T Cooperation between Jilin Province and Chinese Academy of Sciences(No.2022SYHZ0018)。
文摘Water scarcity and soil salinization pose significant challenges to agriculture in the West Liaohe Plain,eastern Inner Mongolia,China.Shallow-buried drip irrigation can improve soil water use efficiency to alleviate water shortage in agriculture and the application of lignite humic acid reduces the adverse effects of soil salinization.However,further research is needed to investigate the effects of different application rates of lignite humic acid and humic acid-based combined amendment on soil physicochemical properties,nutrient contents,and crop yield in saline-sodic farmlands under shallow-buried drip irrigation.A two-year field experiment was conducted with control without any amendment(CK),three treatments amended with 3 t/ha(H1),6 t/ha(H2),and 12 t/ha(H3)lignite humic acid,and three application rates with 15 t/ha(T1),22.5 t/ha(T2),and 30 t/ha(T3)lignite humic acid-based combined amendment in 2021 and2022.The results showed that H3 reduced soil bulk density,p H,electrical conductivity,and total alkalinity,while increasing the contents of soil organic matter,total nitrogen,and available potassium in the two-year experiment.Moreover,the maize yield in H3 increased by an average of 35.5%.T2 decreased soil bulk density,p H,total alkalinity,and increased maize yield by 16.2%,compared to the first year.These results suggest that T2 consistently improved both soil quality and crop yield.Correlation analyses showed that lignite humic acid and its complexes promote maize growth and increase yield by increasing soil organic matter and total nitrogen while reducing soil salinity and total alkalinity.Based on the comprehensive analysis of the field data and the results of the comprehensive evaluation of soil quality,it was determined that the appropriate improvement measures for saline-sodic farmlands under shallow-buried drip irrigation are the application of 12 t/ha of lignite humic acid and 22.5 t/ha of lignite humic acid-based combined amendment.This study demonstrates the effectiveness of lignite humic acid and its combined amendment in mitigating the constraints of saline-sodic farmlands and enhancing crop yields,providing a sustainable solution for improving saline-sodic farmlands in the West Liaohe Plain.
文摘An amendment to the Electoral Law of the National People’s Congress and Local People’s Congresses of the People’s Republic of China providing equal legislative representation to rural and urban people was ratified at the closing meeting of the Third Session of the 1 1th
基金supported by the National Natural Science Foundation of China(41930756 and 42077041)。
文摘Population growth and growing demand for livestock products produce large amounts of manure,which can be harnessed to maintain soil sustainability and crop productivity.However,the impacts of excessive manure application on crop yields,nitrogen(N)-cycling processes and microorganisms remain unknown.Here,we explored the effects of 20-year of excessive rates(18 and 27 Mg ha^(–1)yr^(–1))of pig manure application on peanut crop yields,soil nutrient contents,N-cycling processes and the abundance of N-cycling microorganisms in an acidic Ultisol in summer and winter,compared with none and a regular rate(9 Mg ha^(–1)yr^(–1))of pig manure application.Long-term excessive pig manure application,especially at the high-rate,significantly increased soil nutrient contents,the abundance of N-cycling functional genes,potential nitrification and denitrification activity,while it had a weaker effect on peanut yield and plant biomass.Compared with manure application,seasonality had a much weaker effect on N-cycling gene abundance.Random forest analysis showed that available phosphorus(AP)content was the primary predictor for N-cycling gene abundance,with significant and positive associations with all tested N-cycling genes.Our study clearly illustrated that excessive manure application would increase N-cycling gene abundance and potential N loss with relatively weak promotion of crop yields,providing significant implications for sustainable agriculture in the acidic Ultisols.
基金supported by the National Key R&D Program of China (No.2019YFC1803704)。
文摘The digestibility of cadmium(Cd)in brown rice is directly related to amino acid metabolism in rice and human health.In our field study,three kinds of alkaline calcium-rich soil inorganic amendments(SIAs)at three dosages were applied to produce safe rice and improve the quality of rice in Cd-contaminated paddy.With the increased application of SIA,Cd content in iron plaque on rice root significantly increased,the transfer of Cd from rice root to grain significantly decreased,and then Cd content in brown rice decreased synchronously.The vitro digestibility of Cd in brown rice was estimated by a physiologically based extraction test.Results showed that more than 70%of Cd in brown rice could be digested by simulated gastrointestinal juice.Based on the total and digestible Cd contents in brown rice to evaluate the health risk,the application of 2.25 ton SIA/ha could produce safe rice in acidic slightly Cd-contaminated paddy soils.The amino acids(AAs)in brown rice were determined by high-performance liquid chromatography.The contents of 5 key AAs(KAAs)that actively respond to environmental changes increased significantly with the increased application of SIA.The structural equation model indicated that KAAs could be affected by the Cd translocation capacity from rice root to grain,and consequently altered the ratio of indigestible Cd in brown rice.The formation of indigestible KAAs-Cd complexes by combining KAAs(phenylalanine,leucine,histidine,glutamine,and asparagine)with Cd in brown rice could be considered a potential mechanism for reducing the digestibility of Cd.
基金Supported by Major Technological Innovation Projects of Hubei Province (2017ABA157)Action Plan for Science and Technology Support of Colleges Serving Hubei Rural Revitalization (BXLBX0266)。
文摘Chemical immobilization,as a cost-effective and environmentally friendly technique,has been widely researched in the remediation of cadmium(Cd)-contaminated soil.The key is to find appropriate amendments and optimize their use.In this study,the effects of the application of an inorganic material(phosphorus slag(PS))and organic materials(biochar(BC)and beer lees(BL)),individually or combinedly on the immobilization of Cd in contaminated soil and subsequent bioaccumulation in Chinese cabbage were investigated.The results showed that PS and PS+BL were more effective in decreasing exchangeable Cd(EX-Cd)than other treatments,decreased by 91.2%in the PS treatment and by 64.0%in the PS+BL treatment.However,the soil enzyme activity and soil microbial activity decreased in the treatment with PS alone.In contrast,the combination use of PS and BL could increase soil enzyme activity,soil microbial activity,and functional diversity,and decrease EX-Cd as well.Moreover,the PS+BL treatment reduced the accumulation of Cd in Chinese cabbage most effectively,81.5%in roots and 72.5%in shoots.This treatment could also increase the aboveground height and chlorophyll content of Chinese cabbage while reducing the content of malondialdehyde(MDA).Thus,the PS+BL treatment is highly recommended for Cd immobilization,as it can improve soil quality and reduce Cd accumulation in Chinese cabbage at the same time and hence promote plant growth.
基金partly funded by the Al Ain MunicipalityNational Water and Energy Center, United Arab Emirates University。
文摘Public urban greenery greatly contributes to the residential and tourist value of cities in the Gulf Region,but due to the hyper-arid climatic conditions,the cost of irrigation and plant maintenance is very high.Existing strategies to reduce the monetary and ecological costs involve the cultivation of native xerophytic plantations,and/or the use of soil improvers to increase water-and nutrient-holding capacity of the sandy soils.Various soil improvers based on mineral,organic,or synthetic materials have entered the United Arab Emirates(UAE)market in recent years,but there is considerable uncertainty about how they should best be used in combination with ornamental plant stands involving xerophytic native plants.The present study investigated the effect of soil amendment and deep pipe irrigation on perennial ornamental plant stands involving native plants(Tephrosia appolinea(Gel.)Link in combination with Aerva javanica(Burm.f.)Juss.ex Schult.)and native-exotic plants(T.appolinea in combination with Ruelia simplex C.Wright)either or not topsoil and subsoil amendment with bentonite and hydrophobic sand under the irrigation water supply of less than 50%of reference evapotranspiration(ET0).After one year of cultivation,T.appolinea and A.javanica(native vs.native)produced high biomass and exhibited high water use efficiency(WUE)as compared with T.appolinea and R.simplex(native vs.exotic)combination given that no significant differences were found under the soil amendment treatments.All stands thrived under irrigation water supply far below what is usually supplied to exotic ornamental stands in public parks of the Al Ain City,the UAE.However,subsoil amendment in combination with deep pipe irrigation reduced the occurrence of weeds and increased the overall plant rooting depth.Our results suggest that subsoil amendment and irrigation up to 60-80 cm depth can potentially control ephemeral weed infestation,which is a great challenge in various plant production systems of the Gulf Region.The results of the present study suggest that the impact of soil amendment on the WUE of exotic plants is marginal and might not be economically justified.Replacing exotic with native ornamental plant species seems to have a far greater water-saving potential than the amendment of the soil,while weeds can be suppressed in the absence of topsoil moisture.
基金funded by the National Natural Science Foundation of China(No.U20A20115)Australian Research Council Linkage Project(No.LP160100598)+2 种基金China Scholarship Council(No.201906350122)the Key Platform and Scientific Research Projects of Guangdong Provincial Education Department,China(No.2020KCXTD006)Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control,China(No.2023B1212060002)。
文摘Excess available K and Fe in Fe ore tailings with organic matter amendment and water-deficiencies may restrain plant colonization and growth,which hinders the formation of eco-engineered soil from these tailings for sustainable and cost-effective mine site rehabilitation.Arbuscular mycorrhizal(AM)fungi are widely demonstrated to assist plant growth under various unfavorable environments.However,it is still unclear whether AM symbiosis in tailings amended with different types of plant biomass and under different water conditions could overcome the surplus K and Fe stress for plants in Fe ore tailings,and if so,by what mechanisms.Here,host plants(Sorghum sp.Hybrid cv.Silk),either colonized or noncolonized by the AM fungi(Glomus spp.),were cultivated in lucerne hay(LH,C:N ratio of 18)-or sugarcane mulch(SM,C:N ratio of 78)-amended Fe ore tailings under well-watered(55%water-holding capacity(WHC)of tailings)or water-deficient(30%WHC of tailings)conditions.Root mycorrhizal colonization,plant growth,and mineral elemental uptake and partitioning were examined.Results indicated that AM fungal colonization improved plant growth in tailings amended with plant biomass under water-deficient conditions.Arbuscular mycorrhizal fungal colonization enhanced plant mineral element uptake,especially P,both in the LH-and SM-amended tailings regardless of water condition.Additionally,AM symbiosis development restrained the translocation of excess elements(i.e.,K and Fe)from plant roots to shoots,thereby relieving their phytotoxicity.The AM fungal roles in P uptake and excess elemental partitioning were greater in LH-amended tailings than in SM-amended tailings.Water deficiency weakened AM fungal colonization and functions in terms of mineral element uptake and partitioning.These findings highlighted the vital role AM fungi played in regulating plant growth and nutrition status in Fe ore tailings technosol,providing an important basis for involvement of AM fungi in the eco-engineered pedogenesis of Fe ore tailings.
文摘In agricultural soils, phosphorus is often limited, leading farmers to employ artificial supplementation through both inorganic and organic fertilization methods due to its restricted availability. Soil fertilization has the potential to augment both the abundance and diversity of bacterial communities. Our study aimed to assess the effects of phosphate amendments, derived from natural phosphate rock, and chemical fertilizers (TSP, NPK), on the density and diversity of bacterial communities within the study plots. We developed and applied eight phosphate amendments during the initial cultivation cycle. Soil samples were collected post 1st and 2nd cultivation cycles, and the quantification of both total and cultivable phosphate-solubilizing bacteria (PSB) was conducted. Additionally, we analyzed bacterial community structure, α-diversity (Shannon Diversity Index, Evenness Index, Chao1 Index). The combination of natural phosphate rock (PR) and chemical fertilizers (TSP, NPK) significantly increased (p 7 bacteria/g dry soil) and phosphate-solubilizing bacteria (0.01 to 6.8 × 107 PSB/g dry soil) in comparison to unamended control soils. The diversity of bacterial phyla (Firmicutes, Actinobacteria, Proteobacteria, Halobacterota, Chloroflexia) observed under each treatment remained consistent regardless of the nature of the phosphate amendment applied. However, changes in the abundance of the bacterial phyla populations were observed as a function of the nature of the phosphate amendment or chemical fertilizer. It appears that the addition of excessive natural phosphate rock does not alter the number and the diversity of soil microorganisms population despite successive cultivation cycles. However, the addition of excessive chemical fertilizer reduces soil microorganisms density and structure after the 2nd cultivation cycle.
文摘Ploughing and fertilization practices in rice-wheat system have deteriorated the soil carbon (C) pools. Conservation agriculture (CA) based management approaches have proven to enhance C sequestration and reverse the loss of soil-organic-carbon (SOC), which further enhances soil fertility. Different fractions of SOC pools react to the alterations in management practices and indicate changes in SOC dynamics as compared to total C in the soil. Higher SOC levels in soil have been observed in case of reduced/no-till (NT) practices than conventional tillage (CT). However, between CT and zero tillage/NT, total SOC stocks diminished with an increase in soil depth, which demonstrated that the benefits of SOC are more pronounced in the topsoil under NT. Soil aggregation provides physical protection to C associated with different-sized particles, thus, the improvement in soil aggregation through CA is an effective way to mitigate soil C loss. Along with less soil disturbance, residual management, suitable crop rotation, rational application of manures and fertilizers, and integrated nutrient management have been found to be effective in not only improving soil C stock but also enhancing the soil health and productivity. Thus, CA can be considered as a potential method in the build-up of SOC of soil in rice-wheat system.
文摘Global mean surface air temperature is expected to increase 1.1˚C - 6.4˚C by the end of 21st century which may affect rice productivity and methane emissions in the future climate. This experiment was conducted to investigate the response of rice cultivars to elevated air temperature (+1.5˚C higher than ambient) and soil amendments in regards to rice yield, yield scaled methane emissions and global warming potentials. The experimental findings revealed that replacement of inorganic fertilizers (20% - 40% of recommended NPKS) with Vermicompost, Azolla biofertilizer, enriched sugarcane pressmud, rice husk biochar and silicate fertilization increased rice yield 13.0% - 23.0%, and 11.0% - 19.0% during wet aman and dry boro season, respectively. However, seasonal cumulative CH4 fluxes were decreased by 9.0% - 25.0% and 5.0% - 19.0% during rainfed wet aman and irrigated dry boro rice cultivation, respectively with selected soil amendments. The maximum reduction in seasonal cumulative CH4 flux (19.0% - 25.0%) was recorded with silicate fertilization and azolla biofertilizer amendments (9.0% - 13.0%), whereas maximum grain yield increment 10.0 % - 14.0% was found with Vermicompost and Sugarcane pressmud amendments compared to chemical fertilization (100% NPKS) treated soils at ambient air temperature. However, rice grain yield decreased drastically 43.0% - 50.0% at elevated air temperature (3˚C higher than ambient air temperature), eventhough accelerated the total cumulative CH4 flux as well as GWPs in all treatments. Maximum seasonal mean GWPs were calculated at 391.0 kg CO2 eq·ha−1 in rice husk biochar followed by sugarcane pressmud (mean GWP 387.0 kg CO2 eq·ha−1), while least GWPs were calculated at 285 - 305 kg CO2 eq·ha−1 with silicate fertilizer and Azolla biofertilizer amendments. Rice cultivar BRRI dhan 87 revealed comparatively higher seasonal cumulative CH4 fluxes, yield scaled CH4 flux and GWPs than BRRI dhan 71 during wet aman rice growing season;while BRRI dhan 89 showed higher cumulative CH4 flux and GWPs than BINA dhan 10 during irrigated boro rice cultivation. Conclusively, inorganic fertilizers may be partially (20% - 40% of the recommended NPKS) replaced with Vermicompost, azolla biofertilizer, silicate fertilizer and enriched sugarcane pressmud compost for sustainable rice production and decreasing GWPs under elevated air temperature condition.
文摘Soil contamination by hydrocarbons poses numerous environmental, health and agricultural problems. The degradation of these pollutants can occur naturally but very slowly. It is therefore generally necessary to stimulate this degradation by different means. Thus, this study aimed to improve the bio-degradation of diesel and crude oil in a Ghanaian soil by biostimulation. For this, the sampled soil was characterized by standard methods and contaminated with diesel and crude oil at a proportion of 1% (w/w). Then, contaminated soil samples were supplemented with biochar-compost, poultry manure or cow dung at the proportion of 10% (w/w). Periodically, fractions of these samples were taken to evaluate the density of hydrocarbon utilizing bacteria (HUB) and the residual quantities of diesel or crude oil. The characteristics of the soil used show the need for supplementation for better degradation of hydrocarbons. The results of the study show that supplementing the soil with organic substrates increases HUB loads in soils contaminated by diesel and crude oil. They also show that the residual quantities of diesel and crude oil are generally significantly lower in supplemented soils (p = 0.048 and p < 0.0001 respectively). In addition, the study shows that degradation was generally greater in soils contaminated by diesel compared to those contaminated by crude oil, especially at the end of the study.
文摘In arid and semiarid regions such as Niger, irrigated agriculture leads to soil salinization, particularly through irrigation water salts, and has adverse effects on crop production such as vegetable crops including onion. The main objective of this study, conducted in the experimental site of Djibo Hamani University of Tahoua in Niger, was to evaluate the effects of organic fertilizer on the growth and yield of onion crops irrigated with saline water. The experiment was performed in split-plot design to test tree type of fertilizer (chemical fertilizer, compost and millet glumes) and four (04) levels of irrigation water salinity in electrical conductivity values (ECw) (S0 = 0.28 dS/m as control, S1 = 2 dS/m, S2 = 4 dS/m and S3 = 6 dS/m). The growth parameters and bulb yield were evaluated during 4 months of onion cropping season. The results showed that the use of irrigation saline water significantly decreased the growth and bulb yield of onion crops. The yield in onion bulbs is 1.55 to 3.94 times higher with control (0.28 dS/m) than that with high saline water (ECw = 6 dS/m). Compared to control in irrigation water, the reduction in fresh onion bulb yield was 38.8, 52.6 and 63.5% respectively for ECw of 2, 4 and 6 dS/m. Furthermore, the application of organic fertilizers, particularly compost, improves salt-tolerance of onion crops in order to promote growth and bulb yield. Indeed, when irrigating onion crops with saline water (ECw of 2, 4 and 6 dS/m), the onion bulb yield is significantly higher under compost than under chemical fertilizer and glumes. At high irrigation saline water (ECw = 6 dS/m), the yield in onion bulbs is 1.9 and 2.1 times higher under compost than that under chemical fertilizer and glumes respectively. Thus, the compost is the promising organic amendment in a semiarid region of Tahoua in Niger to reduce the adverse effects of irrigation saline water on onion crop production.
