Stress corrosion cracking （SCC） of X70 pipeline steel in simulated solution of the acidic soil in Yingtan in China was investigated using slow strain rate test （SSRT）, SEM and potentiodynamic polarization techniqu...Stress corrosion cracking （SCC） of X70 pipeline steel in simulated solution of the acidic soil in Yingtan in China was investigated using slow strain rate test （SSRT）, SEM and potentiodynamic polarization technique. Experiment results indicate that X70 steel is highly susceptible to SCC as applied potential reduces, which is manifested in loss of toughness and brittle fracture. Constaat polarization current can detect the occurrence of SCC. The lower the polarization current is the sooner stress corrosion cracking occurs. The SCC mechanisms are different at varying potentials. When potential is higher than open circuit potential, anodic process controls SCC, whereas when potential is far lower than open circuit potential, cathodic process controls SCC, and between these two potential regions, a combined electrochemical process controls the SCC. Stress or strain has a synergistic effect with electrochemical reactions to accelerate the cathodic hydrogen evolution process, which makes the X70 pipeline steel to be more susceptible to SCC.展开更多
Aluminum （AI） toxicity and phosphorous （P） deficiency are two major limiting factors for plant growth on acidic soils. Thus, the physiological mechanisms for AJ tolerance and P acquisition have been intensively st...Aluminum （AI） toxicity and phosphorous （P） deficiency are two major limiting factors for plant growth on acidic soils. Thus, the physiological mechanisms for AJ tolerance and P acquisition have been intensively studied. A commonly observed trait is that plants have developed the ability to utilize organic acid anions （OAs; mainly malate, citrate and oxalate） to combat AI toxicity and P deficiency. OAs secreted by roots into the rhizosphere can externally chelate Al^3＋ and mobilize phosphate （Pi）, while OAs synthesized in the cell can internally sequester Al^3＋ into the vacuole and release free Pi for metabolism. Molecular mechanisms involved in OA synthesis and transport have been described in detail. Ensuing genetic improvement for AI tolerance and P efficiency through increased OA exudation and/or synthesis in crops has been achieved by transgenic and marker-assisted breeding. This review mainly elucidates the crucial roles of OAs in plant Al tolerance and P efficiency through summarizing associated physiological mechanisms, molecular traits and genetic manipulation of crops.展开更多
In order to investigate stress corrosion cracking （SCC） of X70 pipeline steel and its weld joint area in acidic soil environ- ment in China, two simulating methods were used： one was to obtain bad microstructures i...In order to investigate stress corrosion cracking （SCC） of X70 pipeline steel and its weld joint area in acidic soil environ- ment in China, two simulating methods were used： one was to obtain bad microstructures in heat affected zone by annealing at 1300 ℃ for 10 min and then, quenching in water; the other was to get different simulating solutions of acidic soil in Yingtan in south- east China. The SCC susceptibilities of X70 pipeline steel before and after quenching in the simulating solutions were analyzed using slow stain rate test （SSRT） and potentiodynamic polarization technique to investigate the SCC electrochemical mechanism of different microstructures further. The results show that SCC appears in the original microstructure and the quenched microstructure as the polarization potential decreases. Hydrogen revolution accelerates SCC of the two tested materials within the range of-850 mV to -1200 mV vs. SCE. Microstructural hardening and grain coarsening also increase SCC. The SCC mechanisms are different, anodic dissolution is the key of causing SCC as the polarization potential is higher than the null current potential, and hydrogen embrittlement will play a more important role to SCC as the polarization potential lower than the null current potential.展开更多
With the hypothesis that iron(Fe) deficiency responsive genes may play a role in Fe toxicity conditions,we studied five such genes OsNAS1,OsNAS3,OsIRO2,OsIRO3 and OsYSL16 across six contrasting rice genotypes for expr...With the hypothesis that iron(Fe) deficiency responsive genes may play a role in Fe toxicity conditions,we studied five such genes OsNAS1,OsNAS3,OsIRO2,OsIRO3 and OsYSL16 across six contrasting rice genotypes for expression under high Fe and low phosphorus(P) conditions,and sequence polymorphism.Genotypes Sahbhagi Dhan,Chakhao Poirieton and Shasharang were high yielders with no bronzing symptom visible under Fe toxic field conditions,and BAM350 and BAM811 were low yielders but did not show bronzing symptoms.Hydroponic screening revealed that the number of crown roots and root length can be traits for consideration for identifying Fe toxicity tolerance in rice genotypes.Fe contents in rice roots and shoots of a high-yielding genotype KMR3 showing leaf bronzing were significantly high.In response to 24 h high Fe stress,the expression levels of OsNAS3 were up-regulated in all genotypes except KMR3.In response to 48 h high Fe stress,the expression levels of OsNAS1 were3-fold higher in tolerant Shasharang,whereas in KMR3,it was significantly down-regulated.Even in response to 7 d excess Fe stress,the transcript abundances of OsIRO2 and OsNAS3 were contrasting in genotypes Shasharang and KMR3.This suggested that the reported Fe deficiency genes had a role in Fe toxicity and that in genotype KMR3 under excess Fe stress,there was disruption of metal homeostasis.Under the 48 h low P conditions,OsIRO2 and OsYSL16 were significantly up-regulated in Fe tolerant genotype Shasharang and in low P tolerant genotype Chakhao Poirieton,respectively.In silico sequence analysis across 3 024 rice genotypes revealed polymorphism for 4 genes.Sequencing across OsIRO3and OsNAS3 revealed nucleotide polymorphism between tolerant and susceptible genotypes for Fe toxicity.Non-synonymous single nucleotide polymorphisms and insertion/deletions(InDels) differing in tolerant and susceptible genotypes were identified.A marker targeting 25-bp InDel in OsIRO3,when run on a diverse panel of 43 rice genotypes and a biparental population,was associated with superior performance for yield under acidic lowland field conditions.This study highlights the potential of one of the vital genes involved in Fe homeostasis as a genic target for improving rice yield in acidic soils.展开更多
Potassium chloride, Na-pyrophosphate, CuCl2, NH4-oxalate, dithionite-citrate-bicarbonate (DCB) and Na-citrate solutions were employed to extract aluminum (Al) and iron (Fe) sequentially and separately from 15 acidic s...Potassium chloride, Na-pyrophosphate, CuCl2, NH4-oxalate, dithionite-citrate-bicarbonate (DCB) and Na-citrate solutions were employed to extract aluminum (Al) and iron (Fe) sequentially and separately from 15 acidic soils located at the Mangshan Mountains, Hunan Province, China. Many evidences showed that separate pyrophosphate extracted mainly KCI-extractable Al, organo-Al complexes and some inorganic Al compounds, whereas separate CuCl2 extracted KCl-extractable Al and some organo-Al complexes. CuCl2 extracted much less amounts of Al than pyrophosphate did from the soils. Separate oxalate did not extract all KCl-Pyrophosphate- CuCl2 -oxalate sequentially extractable Al and Fe. Also, separate DCB did not extract all KCl- pyrophosphate- CuCl2 -oxalate- DCB sequentially extractable Al. The forms of Al extracted by oxalate and DCB from the soils were majorly noncrystalline. The interlayered materials of 1.4-nm intergrade minerals of the soils were attributed mainly to hydroxy Al polymers.展开更多
A 32P isotope kinetic approach was used to describe the chemical status and bioavailability of phosphorusin 32 acidic soils from subtropical China. By determining the residual radioactivity rt, in soil solution atdiff...A 32P isotope kinetic approach was used to describe the chemical status and bioavailability of phosphorusin 32 acidic soils from subtropical China. By determining the residual radioactivity rt, in soil solution atdifferent time, t, after introduction of the isotope in an amount of R into the steady soiLwater system, awell-defined isotope kinetic model was established, and upon this model the decrease rate, n, of log(Tt/R)with respect to logt, the mean sojourn time of phosphate ions in solution, the mean exchange rate and themean flux of phosphate ions between soil solid and solution phases were calculated. Other parameters, suchas the exchangeable P within the first minute of isotope exchange (E1), and P in various compartments thatcould be exchanged with solution phosphate ions at different periods of time, were also obtained. For theseacidic soils, the r1/R had a significant correlation with the contents of clay and free Al203 where r1 is theradioactivity in solution 1 minute after introduction of the isotope into the system. Parameter n also hada significant correlation with clay content and a negative correlation with soil pH. E1 values and Cp, theP concentration in soil solution, also significantly correlated with clay and sesquioxide contents of the soils.These indicated that these isotope kinetic parameters were largely infiuenced by P-fixing components of thesoils. For the soils with strong P-fixing ability the E1 values overestimated labile P pools and hence theircorrelations with A values and plant P uptake were not significant. The other isotope kinetic parameters alsohad no significant correlation with plant P uptake. On the other hand, the conventional chemical-extractedP correlated better with plant P uptake. It was concluded that the isotope kinetic method could assess theP chemical status yet it would be inappropriate in predicting plant available P for soils with a high P-fixingability as the problem of an overestimation of soil labile P in these soils was inevitable.展开更多
[Objectives] A field experiment was carried out with biogas manure replacing partial chemical fertilizer to discuss the effects on growth and development of summer maize and soil environment,so as to provide theoretic...[Objectives] A field experiment was carried out with biogas manure replacing partial chemical fertilizer to discuss the effects on growth and development of summer maize and soil environment,so as to provide theoretical basis for efficient utilization and zero growth of chemical fertilizer. [Methods]The summer maize field experiment was carried out in Muping District,Yantai City,with conventional fertilization as control,and sole application of biogas manure,biogas manure ＋ 80% chemical fertilizer and biogas manure ＋ 60% chemical fertilizer as three treatments. Growth indices,yield and yield components of summer maize and soil nutrient utilization status were determined. [Results] On the basis of reduced fertilizer application,the application of biogas manure could significantly promote growth of summer maize,and its plant height,stem diameter,ear position and dry weight per plant significantly increased compared with the CK. Remarkable yield increasing effect was obtained on summer maize,and among the various treatments,treatment BM ＋ CF80 had the highest yield,which was 19. 91% higher than the CK. Furthermore,the combined application of biogas manure and chemical fertilizer not only could improve soil acidity（ soil pH was improved by 0. 12 unit）,but also could improve soil rapidly available potassium content and reduce soil alkali-hydrolyzable nitrogen content. [Conclusions]Comprehensively,combined application of biogas manure and 80% of chemical fertilizer is the best for growth and development of summer maize and improvement of soil character.展开更多
This paper described the use of fy ash for soil amelioration of acidic soils to promote plant growth.In mining sites,acid sulfate soils/rocks,which contain sulfde minerals(e.g.pyrite FeS_(2)),have appeared as a result...This paper described the use of fy ash for soil amelioration of acidic soils to promote plant growth.In mining sites,acid sulfate soils/rocks,which contain sulfde minerals(e.g.pyrite FeS_(2)),have appeared as a result of overburden excavation.The excessively acidic condition inhibits plant growth due to the dissolution of harmful elements,such as Al,Fe,and Mn.Fly ash,an alkaline byproduct of coal combustion generated in thermal power plants is expected to be adopted to ameliorate acidic soils.However,the mixing ratio of fy ash must be considered because excessive addition of fy ash can have a negative impact on plant growth due to its physical/chemical properties.The pot trials using Acacia mangium demonstrate the evolution of plant growth with a 5%–10%addition of fy ash into acidic soil.When the acidic soil has a high potential for metal dissolution,the metal ions leached from the acidic soil are large,making it difcult to improve plant growth due to osmotic and ionic stress.This work suggests that the efects of fy ash on metal ions leached from the soil have to be considered for the amelioration of acidic soil.展开更多
Teak （Tectona grandis L.f.） is widely planted in the world due to its high market demand, economic, ecological and social value. Its plantations have mostly been established and expanded into sites that are acidic t...Teak （Tectona grandis L.f.） is widely planted in the world due to its high market demand, economic, ecological and social value. Its plantations have mostly been established and expanded into sites that are acidic to severely acidic in southern China. But, there are no available and specific evidence-based nutrient management techniques. To better recognize and understand the relationship between teak tree growth and nutrient content in the foliage and soil and establish nutrient norms are critical to optimally manage these young plantations. We studied the foliar nutrient and soil chemistry in 19 representative teak plantations aged 5-8 years. Regression analysis indicated that the mean annual increment of teak volume was linearly and positively correlated with foliar N, Ca, Fe and B concentrations, with soil base saturation percentage, available P and Zn concentrations, and negatively correlated with soil Al concentration. Only if the Ca and Mg contents in soil were enhanced, could the increase in soil base saturation percentage benefit teak growth. A revised classification of low-and high-yielding stands was established by using a sorting method of principal components over 6 foliar macro and 8 micro elements in a Diagnosis and Recommendation Integrated System （DRIS）. Specific DRIS norms for teak plantations in acid soils were derived. The nutrient balance of N, P, K Ca, Mg, Zn, B with Fe or A1, Ca with Mg, and Fe with AI provided a key to promote the growth of teak in acid soils. Meanwhile, soil Zn was also found as a primary trace element that affected teak growth in this study.展开更多
The popularization of <i>Dioscorea dumetorum</i> (Dioscoreaceae), a nutritious yam species is still marginal due to constraints such as the low interest of research, poor cultural practices, insufficient a...The popularization of <i>Dioscorea dumetorum</i> (Dioscoreaceae), a nutritious yam species is still marginal due to constraints such as the low interest of research, poor cultural practices, insufficient and expensive seeds, pests, and diseases. The latter pushes producers to use about 50% of their harvest as seed for the next planting season. The lack of a specific fertilizer formulation for yam production on the oxysols of Cameroon is another constraint. This study was aimed at enhancing the availability of quality seeds through the characterization of five yam accessions. One experiment was performed to determine the effect of cultivar and origin of tuber sets on their germination rate. The <span>second concerned the evaluation of cultivars and soil treatment effects on ag</span>ronomic parameters of yam seedlings. Yam cultivars were subjected to nine fertilizer formulations as follows: T0: no fertilizer;T1: mycorrhizal fungi (MF) + 150 g manure + peanut waste;T2: 25 g chemical fertilizer (20.10.10);T3: MF + peanut waste;T4: 16 g chemical fertilizer (12.6.20);T5: 25 g (20.10.10) +100 g CaO + 150 g manure;T6: 100 g CaO + 150 g manure;T7: 20 g tropicote + 2 g DAP (Diammonium phosphate, a reference starter fertilizer coded N18P46) + 100 g CaO + 150 g manure;and T8: mycorrhiza. These treatments were tested in a factorial design. Results show that Ibo sweet 3 and Mabondji sweet white 1 yam accessions were less affected by anthracnose disease on the aerial parts. Guzang 1 showed the best germination rate and yield, making it appropriate for cultivation in the region. Soil treatments, T2, T5, T7 and T8 significantly increased the yield of yam cultivars. Mycorrhiza treatment alone gave a better response to seed weight, indicating the interest of this biofertilizer as a solution for good seedling production. These fertilizer treatments can be recommended to farmers for more seed production with optimum seed weight (300 g).展开更多
Soil acidification negatively affects plant growth,soil microbial composition and diversity,and the sustainability of agricultural ecosystems.The primary sources of soil acidity include base cations(BCs)leaching loss,...Soil acidification negatively affects plant growth,soil microbial composition and diversity,and the sustainability of agricultural ecosystems.The primary sources of soil acidity include base cations(BCs)leaching loss,the weathering of aluminum-containing minerals,excess cation uptake by plants,and the transformation of nitrogen,carbon,and sulfur compounds by soil microorganisms.Soil acidity reflects the degree of soil acidification and is characterized by the active acidity(intensity factor)and exchangeable acidity(quantity factor),while soil acid buffering capacity(Acid-BC)(capacity factor)controls the degree and rate of soil acidification.Biochar,as an alkaline,porous and carbonrich matter,not only reduces soil active and exchangeable acidity but also enhances the Acid-BC.Having a variety of BCs and oxygen-containing functional groups(OFGs),biochar improves acidic soil mainly through liming effect,cation exchange,complexation,and precipitation reactions.Thus,to improve acidic soils,the application of biochar may be a better alternative than conventional liming materials.However,further studies into re-acidification of biochar-amended soil due to biochar aging,nitrification of excess fertilizer nitrogen and their interaction are still required by binding the mechanistic comprehension of biochar-to-soil interactions and prolonged field researches.展开更多
Pyrrolizidine alkaloids(PAs)and their N-oxides(PANOs)are phytotoxins produced by various plant species and have been emerged as environmental pollutants.The sorption/desorption behaviors of PAs/PANOs in soil are cruci...Pyrrolizidine alkaloids(PAs)and their N-oxides(PANOs)are phytotoxins produced by various plant species and have been emerged as environmental pollutants.The sorption/desorption behaviors of PAs/PANOs in soil are crucial due to the horizontal transfer of these natural products from PA-producing plants to soil and subsequently absorbed by plant roots.This study firstly investigated the sorption/desorption behaviors of PAs/PANOs in tea plantation soils with distinct characteristics.Sorption amounts for seneciphylline(Sp)and seneciphylline-N-oxide(SpNO)in three acidic soils ranged from 2.9 to 5.9μg/g and 1.7 to 2.8μg/g,respectively.Desorption percentages for Sp and SpNO were from 22.2%to 30.5%and 36.1%to 43.9%.In the mixed PAs/PANOs systems,stronger sorption of PAs over PANOs was occurred in tested soils.Additionally,the Freundlich models more precisely described the sorption/desorption isotherms.Cation exchange capacity,sand content and total nitrogen were identified as major influencing factors by linear regression models.Overall,the soils exhibiting higher sorption capacities for compounds with greater hydrophobicity.PANOs were more likely to migrate within soils and be absorbed by tea plants.It contributes to the understanding of environmental fate of PAs/PANOs in tea plantations and provides basic data and clues for the development of PAs/PANOs reduction technology.展开更多
The widespread occurrence of acidic soils presents a major challenge for agriculture,as it hampers productivity via a combination of mineral toxicity,nutrient deficiency,and poor water uptake.Conventional remediation ...The widespread occurrence of acidic soils presents a major challenge for agriculture,as it hampers productivity via a combination of mineral toxicity,nutrient deficiency,and poor water uptake.Conventional remediation methods,such as amending the soil with lime,magnesium,or calcium,are expensive and not environmentally friendly.The most effective method to mitigate soil acidity is the cultivation of acid-tolerant cultivars.The ability of plants to tolerate acidic soils varies significantly,and a key factor influencing this tolerance is aluminum(Al)toxicity.Therefore,understanding the physiological,molecular,and genetic underpinnings of Al tolerance is essential for the successful breeding of acid-tolerant crops.Different tolerance mechanisms are regulated by various genes and quantitative trait loci in various plant species,and molecular markers have been developed to facilitate gene cloning and to support marker-assisted selection for breeding Al-tolerant cultivars.This study provides a comprehensive review of the current developments in understanding the physiological and molecular mechanisms underlying Al resistance.Through the application of genome-wide association methods,it is expected that new Al-resistant genes can be identified and utilized to cultivate Al-resistant varieties through intercrossing,backcrossing,and molecular marker-assisted selection,promoting the sustainable use of acidic soils.展开更多
[Objectives]This study was conducted to improve acidic soil and enhance the quality of tobacco leaves.[Methods]The effects of different microbial fertilizers on improving acidic tobacco-planting soil and tobacco leaf ...[Objectives]This study was conducted to improve acidic soil and enhance the quality of tobacco leaves.[Methods]The effects of different microbial fertilizers on improving acidic tobacco-planting soil and tobacco leaf quality were investigated through plot experiments.[Results]The application of microbial fertilizers could improve the pH value of acidic soil,and composite microbial agent A showed the best application effect.The application of bio-organic fertilizer was beneficial to improving the contents of available phosphorus and available boron in acidic soil.The application of composite microbial agent A was beneficial to improving the contents of available phosphorus and available potassium in acidic soil,and could promote the growth of tobacco plants and improve the economic traits of flue-cured tobacco and the coordination of chemical components in tobacco leaves.The application of composite microbial agent B led to a downward trend in the content of available boron in acidic soil.The application of composite microbial agent B could promote the absorption of nutrients by tobacco plants,and improve their disease resistance and the quality of tobacco leaves.Due to the differences in functional microorganisms contained,the application effects of different microbial fertilizers in improving acidic tobacco-planting soil and improving tobacco leaf quality varied.Overall,the application of microbial fertilizers could increase soil pH,activate soil nutrients,promote tobacco growth,enhance disease resistance,increase tobacco output value,and improve tobacco quality.Microbial fertilizers have good application prospects in improving acidic soil and improving tobacco quality.[Conclusions]The application of microbial fertilizers to improve acidic tobacco-planting soil can ensure the normal growth and development of tobacco plants and the improvement of tobacco leaf quality,achieving high-quality and sustainable development of Zhaotong tobacco.展开更多
Nutrient limiting factors in acidic soils from vegetable fields of the Chongqing suburbs of China were assessed by employing the systematic approach developed by Agro Services International (ASI) including soil testin...Nutrient limiting factors in acidic soils from vegetable fields of the Chongqing suburbs of China were assessed by employing the systematic approach developed by Agro Services International (ASI) including soil testing, nutrient adsorption study, and pot and field experiments to verify the results of soil testing, with a conventional soil test (CST) used for comparison. The ASI method found the moderately acidic soil (W01) to be N and P deficient; the strongly acidic soil (W04) to be N, K and S deficient; and the slightly acidic soil (W09) to be N, K, S, Cu, Mn, and Zn deficient. The CST method showed that W01 had P, B and Cu deficiencies; W04 had N, P and S deficiencies; and W09 had N, P, S, B, Cu, and Zn deficiencies. There were differences between the two methods. Among the two indicator plants selected, the response of sorghum on the three representative acidic soils was more closely related to the ASI results than that of sweet pepper.展开更多
The occurrence of nitri?cation in some acidic forest soils is still a subject of debate.Identi?cation of main nitri?cation pathways in acidic forest soils is still largely unknown.Acidic yellow soil(Oxisol) samples we...The occurrence of nitri?cation in some acidic forest soils is still a subject of debate.Identi?cation of main nitri?cation pathways in acidic forest soils is still largely unknown.Acidic yellow soil(Oxisol) samples were selected to test whether nitri?cation can occur or not in acidic subtropical pine forest ecosystems.Relative contributions of autotrophs and heterotrophs to nitri?cation were studied by adding selective nitri?cation inhibitor nitrapyrin.Soil NH^+_4-N concentrations decreased,but NO^-_3-N concentrations increased signi?cantly for the no-nitrapyrin control during the ?rst week of incubation,indicating that nitri?cation did occur in the acidic subtropical soil.The calculated net nitri?cation rate was 0.49 mg N kg^(-1)d^(-1)for the no-nitrapyrin control during the ?rst week of incubation.Nitrapyrin amendment resulted in a signi?cant reduction of NO^-_3-N concentration.Autotrophic nitri?cation rate averaged0.28 mg N kg^(-1)d^(-1)and the heterotrophic nitri?cation rate was 0.21 mg N kg^(-1)d^(-1)in the ?rst week.Ammonia-oxidizing bacteria(AOB) abundance increased slightly during incubation,but nitrapyrin amendment signi?cantly decreased AOB amo A gene copy numbers by about 80%.However,the ammonia-oxidizing archaea(AOA) abundance showed signi?cant increases only in the last 2weeks of incubation and it was also decreased by nitrapyrin amendment.Our results indicated that nitri?cation did occur in the present acidic subtropical pine forest soil,and autotrophic nitri?cation was the main nitri?cation pathway.Both AOA and AOB were the active biotic agents responsible for autotrophic nitri?cation in the acidic subtropical pine forest soil.展开更多
Electrochemical experiments,slow strain rate tensile testing(SSRT),and scanning electron microscopy were used to investigate the effect of various applied potentials on the stress corrosion cracking(SCC)of X80 pipelin...Electrochemical experiments,slow strain rate tensile testing(SSRT),and scanning electron microscopy were used to investigate the effect of various applied potentials on the stress corrosion cracking(SCC)of X80 pipeline steel in acidic soil containing sulfate-reducing bacteria(SRB).The results demonstrated that when the anodic potential was applied,X80 steel exhibited sensitivity to SCC,which was attributed to anodic dissolution.The SCC sensitivity initially decreased,but then increased with a negative shift in the applied potential.At-1200 mV,SCC was the most sensitive,which corresponded to the substantial cathodic polarisation and toxic impact of SRB,which increased the risk of hydrogen embrittlement.At-850 mV,the SCC sensitivity was the lowest because cathodic polarisation suppressed anodic dissolution.The experimental results can contribute to the prevention and management of SCC in operational pipelines.展开更多
[Objectives]This study was conducted to investigate the effects of biochar-based fertilizer on high yield and quality of green pepper(Zanthoxylum armatum var.novemfolius)and soil nutrient status.[Methods]With green pe...[Objectives]This study was conducted to investigate the effects of biochar-based fertilizer on high yield and quality of green pepper(Zanthoxylum armatum var.novemfolius)and soil nutrient status.[Methods]With green pepper and pepper field soil as the research subjects,four treatments were set up,namely,conventional fertilization(T_(1)),conventional fertilization+biochar(T_(2)),biochar-based fertilizer 1(T_(3)),and biochar-based fertilizer 2(T_(4)).[Results]The application of biochar-based fertilizer increased green pepper yield by 9.37%-51.12%,with the order of increase being T_(4)>T_(3)>T_(2)>T_(1).In terms of soil nutrients,biochar-based fertilizer raised soil pH by 6.67%-53.33%,with the order of increase being T_(3)>T_(4)>T_(2)>T_(1).The initially strongly acidic soil gradually shifted to weakly acidic and approached neutral,indicating significantly improved soil acidity.The application of biochar-based fertilizer increased the contents of soil organic matter,available nitrogen,available phosphorus,available potassium,available copper,available zinc,available iron,and available manganese.It significantly enhanced green pepper yield,improved soil acidity,and elevated soil nutrient levels.Considering yield,nutrient uptake,and soil nutrient content,biochar-based fertilizer 2(T_(4))was identified as the optimal treatment.[Conclusions]This study provides a theoretical basis for improving green pepper yield and soil amendment.展开更多
The chemical characteristics,element contents,mineral compositions,and the ameliorative effects on acid soils of five biomass ashes from different materials were analyzed. The chemical properties of the ashes varied d...The chemical characteristics,element contents,mineral compositions,and the ameliorative effects on acid soils of five biomass ashes from different materials were analyzed. The chemical properties of the ashes varied depending on the source biomass material. An increase in the concrete shuttering contents in the biomass materials led to higher alkalinity,and higher Ca and Mg levels in biomass ashes,which made them particularly good at ameliorating effects on soil acidity. However,heavy metal contents,such as Cr,Cu,and Zn in the ashes,were relatively high. The incorporation of all ashes increased soil p H,exchangeable base cations,and available phosphorus,but decreased soil exchangeable acidity. The application of the ashes from biomass materials with a high concrete shuttering content increased the soil available heavy metal contents. Therefore,the biomass ashes from wood and crop residues with low concrete contents were the better acid soil amendments.展开更多
This study was conducted to investigate the effects of mixed biochar on the nitrification rate in acidic soils. A15 N tracer experiment with(15 NH4)2 SO4 was conducted to determine the nitrification rates of 4 acidic ...This study was conducted to investigate the effects of mixed biochar on the nitrification rate in acidic soils. A15 N tracer experiment with(15 NH4)2 SO4 was conducted to determine the nitrification rates of 4 acidic agricultural soils with p H 4.03-6.02 in Yunnan Province, Southern China. The accumulation of15 N-NO3-and nitrification rates decreased with the addition of biochar at the end of incubation, suggesting that biochar could be a nitrification inhibitor in acidic fertilized soil. Nitrification rates in soil with p H 4.03 were evidently lower than those in soil with p H 4.81-6.02 with or without biochar. Decreased nitrification rates were detected in the acidic soils with biochar. Soil p H controlled nitrification more than biochar in certain strongly acidic soils.展开更多
基金supported by Chinese National Science and Technology Infrastructure Platforms Construction Project (No.2005DKA10400)Major Foundation in the Tenth Five-Year Development Plan of China (No.50499333-08)
文摘Stress corrosion cracking （SCC） of X70 pipeline steel in simulated solution of the acidic soil in Yingtan in China was investigated using slow strain rate test （SSRT）, SEM and potentiodynamic polarization technique. Experiment results indicate that X70 steel is highly susceptible to SCC as applied potential reduces, which is manifested in loss of toughness and brittle fracture. Constaat polarization current can detect the occurrence of SCC. The lower the polarization current is the sooner stress corrosion cracking occurs. The SCC mechanisms are different at varying potentials. When potential is higher than open circuit potential, anodic process controls SCC, whereas when potential is far lower than open circuit potential, cathodic process controls SCC, and between these two potential regions, a combined electrochemical process controls the SCC. Stress or strain has a synergistic effect with electrochemical reactions to accelerate the cathodic hydrogen evolution process, which makes the X70 pipeline steel to be more susceptible to SCC.
基金financially supported by the National Natural Science Foundation of China(No.U1301212)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB15030202)
文摘Aluminum （AI） toxicity and phosphorous （P） deficiency are two major limiting factors for plant growth on acidic soils. Thus, the physiological mechanisms for AJ tolerance and P acquisition have been intensively studied. A commonly observed trait is that plants have developed the ability to utilize organic acid anions （OAs; mainly malate, citrate and oxalate） to combat AI toxicity and P deficiency. OAs secreted by roots into the rhizosphere can externally chelate Al^3＋ and mobilize phosphate （Pi）, while OAs synthesized in the cell can internally sequester Al^3＋ into the vacuole and release free Pi for metabolism. Molecular mechanisms involved in OA synthesis and transport have been described in detail. Ensuing genetic improvement for AI tolerance and P efficiency through increased OA exudation and/or synthesis in crops has been achieved by transgenic and marker-assisted breeding. This review mainly elucidates the crucial roles of OAs in plant Al tolerance and P efficiency through summarizing associated physiological mechanisms, molecular traits and genetic manipulation of crops.
基金supported by the National Science and Technology Infrastructure Platforms Construction Projects of China (No.2005DKA 10400)the Major Fund in the Tenth Five-Year Development Plan of China (No.50499333-08)
文摘In order to investigate stress corrosion cracking （SCC） of X70 pipeline steel and its weld joint area in acidic soil environ- ment in China, two simulating methods were used： one was to obtain bad microstructures in heat affected zone by annealing at 1300 ℃ for 10 min and then, quenching in water; the other was to get different simulating solutions of acidic soil in Yingtan in south- east China. The SCC susceptibilities of X70 pipeline steel before and after quenching in the simulating solutions were analyzed using slow stain rate test （SSRT） and potentiodynamic polarization technique to investigate the SCC electrochemical mechanism of different microstructures further. The results show that SCC appears in the original microstructure and the quenched microstructure as the polarization potential decreases. Hydrogen revolution accelerates SCC of the two tested materials within the range of-850 mV to -1200 mV vs. SCE. Microstructural hardening and grain coarsening also increase SCC. The SCC mechanisms are different, anodic dissolution is the key of causing SCC as the polarization potential is higher than the null current potential, and hydrogen embrittlement will play a more important role to SCC as the polarization potential lower than the null current potential.
基金supported by the grants from Indian Council of Agricultural Research (Grant No. C30033/415101-036)Department of Biotechnology,Government of India (Grant No. BT/566/NE/U-excel/2016/72)+1 种基金supported by Rajiv Gandhi National FellowshipNational Fellowship for Higher Education of ST Students (Grant No. 201516-NFST-2015-17-ST-3514), respectively, from the Ministry of Tribal Affairs, University Grant Commission, Government of India。
文摘With the hypothesis that iron(Fe) deficiency responsive genes may play a role in Fe toxicity conditions,we studied five such genes OsNAS1,OsNAS3,OsIRO2,OsIRO3 and OsYSL16 across six contrasting rice genotypes for expression under high Fe and low phosphorus(P) conditions,and sequence polymorphism.Genotypes Sahbhagi Dhan,Chakhao Poirieton and Shasharang were high yielders with no bronzing symptom visible under Fe toxic field conditions,and BAM350 and BAM811 were low yielders but did not show bronzing symptoms.Hydroponic screening revealed that the number of crown roots and root length can be traits for consideration for identifying Fe toxicity tolerance in rice genotypes.Fe contents in rice roots and shoots of a high-yielding genotype KMR3 showing leaf bronzing were significantly high.In response to 24 h high Fe stress,the expression levels of OsNAS3 were up-regulated in all genotypes except KMR3.In response to 48 h high Fe stress,the expression levels of OsNAS1 were3-fold higher in tolerant Shasharang,whereas in KMR3,it was significantly down-regulated.Even in response to 7 d excess Fe stress,the transcript abundances of OsIRO2 and OsNAS3 were contrasting in genotypes Shasharang and KMR3.This suggested that the reported Fe deficiency genes had a role in Fe toxicity and that in genotype KMR3 under excess Fe stress,there was disruption of metal homeostasis.Under the 48 h low P conditions,OsIRO2 and OsYSL16 were significantly up-regulated in Fe tolerant genotype Shasharang and in low P tolerant genotype Chakhao Poirieton,respectively.In silico sequence analysis across 3 024 rice genotypes revealed polymorphism for 4 genes.Sequencing across OsIRO3and OsNAS3 revealed nucleotide polymorphism between tolerant and susceptible genotypes for Fe toxicity.Non-synonymous single nucleotide polymorphisms and insertion/deletions(InDels) differing in tolerant and susceptible genotypes were identified.A marker targeting 25-bp InDel in OsIRO3,when run on a diverse panel of 43 rice genotypes and a biparental population,was associated with superior performance for yield under acidic lowland field conditions.This study highlights the potential of one of the vital genes involved in Fe homeostasis as a genic target for improving rice yield in acidic soils.
文摘Potassium chloride, Na-pyrophosphate, CuCl2, NH4-oxalate, dithionite-citrate-bicarbonate (DCB) and Na-citrate solutions were employed to extract aluminum (Al) and iron (Fe) sequentially and separately from 15 acidic soils located at the Mangshan Mountains, Hunan Province, China. Many evidences showed that separate pyrophosphate extracted mainly KCI-extractable Al, organo-Al complexes and some inorganic Al compounds, whereas separate CuCl2 extracted KCl-extractable Al and some organo-Al complexes. CuCl2 extracted much less amounts of Al than pyrophosphate did from the soils. Separate oxalate did not extract all KCl-Pyrophosphate- CuCl2 -oxalate sequentially extractable Al and Fe. Also, separate DCB did not extract all KCl- pyrophosphate- CuCl2 -oxalate- DCB sequentially extractable Al. The forms of Al extracted by oxalate and DCB from the soils were majorly noncrystalline. The interlayered materials of 1.4-nm intergrade minerals of the soils were attributed mainly to hydroxy Al polymers.
文摘A 32P isotope kinetic approach was used to describe the chemical status and bioavailability of phosphorusin 32 acidic soils from subtropical China. By determining the residual radioactivity rt, in soil solution atdifferent time, t, after introduction of the isotope in an amount of R into the steady soiLwater system, awell-defined isotope kinetic model was established, and upon this model the decrease rate, n, of log(Tt/R)with respect to logt, the mean sojourn time of phosphate ions in solution, the mean exchange rate and themean flux of phosphate ions between soil solid and solution phases were calculated. Other parameters, suchas the exchangeable P within the first minute of isotope exchange (E1), and P in various compartments thatcould be exchanged with solution phosphate ions at different periods of time, were also obtained. For theseacidic soils, the r1/R had a significant correlation with the contents of clay and free Al203 where r1 is theradioactivity in solution 1 minute after introduction of the isotope into the system. Parameter n also hada significant correlation with clay content and a negative correlation with soil pH. E1 values and Cp, theP concentration in soil solution, also significantly correlated with clay and sesquioxide contents of the soils.These indicated that these isotope kinetic parameters were largely infiuenced by P-fixing components of thesoils. For the soils with strong P-fixing ability the E1 values overestimated labile P pools and hence theircorrelations with A values and plant P uptake were not significant. The other isotope kinetic parameters alsohad no significant correlation with plant P uptake. On the other hand, the conventional chemical-extractedP correlated better with plant P uptake. It was concluded that the isotope kinetic method could assess theP chemical status yet it would be inappropriate in predicting plant available P for soils with a high P-fixingability as the problem of an overestimation of soil labile P in these soils was inevitable.
基金Supported by Key Research and Development Project of Shandong Province(2016DJ11A07)
文摘[Objectives] A field experiment was carried out with biogas manure replacing partial chemical fertilizer to discuss the effects on growth and development of summer maize and soil environment,so as to provide theoretical basis for efficient utilization and zero growth of chemical fertilizer. [Methods]The summer maize field experiment was carried out in Muping District,Yantai City,with conventional fertilization as control,and sole application of biogas manure,biogas manure ＋ 80% chemical fertilizer and biogas manure ＋ 60% chemical fertilizer as three treatments. Growth indices,yield and yield components of summer maize and soil nutrient utilization status were determined. [Results] On the basis of reduced fertilizer application,the application of biogas manure could significantly promote growth of summer maize,and its plant height,stem diameter,ear position and dry weight per plant significantly increased compared with the CK. Remarkable yield increasing effect was obtained on summer maize,and among the various treatments,treatment BM ＋ CF80 had the highest yield,which was 19. 91% higher than the CK. Furthermore,the combined application of biogas manure and chemical fertilizer not only could improve soil acidity（ soil pH was improved by 0. 12 unit）,but also could improve soil rapidly available potassium content and reduce soil alkali-hydrolyzable nitrogen content. [Conclusions]Comprehensively,combined application of biogas manure and 80% of chemical fertilizer is the best for growth and development of summer maize and improvement of soil character.
文摘This paper described the use of fy ash for soil amelioration of acidic soils to promote plant growth.In mining sites,acid sulfate soils/rocks,which contain sulfde minerals(e.g.pyrite FeS_(2)),have appeared as a result of overburden excavation.The excessively acidic condition inhibits plant growth due to the dissolution of harmful elements,such as Al,Fe,and Mn.Fly ash,an alkaline byproduct of coal combustion generated in thermal power plants is expected to be adopted to ameliorate acidic soils.However,the mixing ratio of fy ash must be considered because excessive addition of fy ash can have a negative impact on plant growth due to its physical/chemical properties.The pot trials using Acacia mangium demonstrate the evolution of plant growth with a 5%–10%addition of fy ash into acidic soil.When the acidic soil has a high potential for metal dissolution,the metal ions leached from the acidic soil are large,making it difcult to improve plant growth due to osmotic and ionic stress.This work suggests that the efects of fy ash on metal ions leached from the soil have to be considered for the amelioration of acidic soil.
基金funded by the research and demonstration project of teak cultivation of the Chinese Ministry of Science and Technology(2012BAD21B01)
文摘Teak （Tectona grandis L.f.） is widely planted in the world due to its high market demand, economic, ecological and social value. Its plantations have mostly been established and expanded into sites that are acidic to severely acidic in southern China. But, there are no available and specific evidence-based nutrient management techniques. To better recognize and understand the relationship between teak tree growth and nutrient content in the foliage and soil and establish nutrient norms are critical to optimally manage these young plantations. We studied the foliar nutrient and soil chemistry in 19 representative teak plantations aged 5-8 years. Regression analysis indicated that the mean annual increment of teak volume was linearly and positively correlated with foliar N, Ca, Fe and B concentrations, with soil base saturation percentage, available P and Zn concentrations, and negatively correlated with soil Al concentration. Only if the Ca and Mg contents in soil were enhanced, could the increase in soil base saturation percentage benefit teak growth. A revised classification of low-and high-yielding stands was established by using a sorting method of principal components over 6 foliar macro and 8 micro elements in a Diagnosis and Recommendation Integrated System （DRIS）. Specific DRIS norms for teak plantations in acid soils were derived. The nutrient balance of N, P, K Ca, Mg, Zn, B with Fe or A1, Ca with Mg, and Fe with AI provided a key to promote the growth of teak in acid soils. Meanwhile, soil Zn was also found as a primary trace element that affected teak growth in this study.
文摘The popularization of <i>Dioscorea dumetorum</i> (Dioscoreaceae), a nutritious yam species is still marginal due to constraints such as the low interest of research, poor cultural practices, insufficient and expensive seeds, pests, and diseases. The latter pushes producers to use about 50% of their harvest as seed for the next planting season. The lack of a specific fertilizer formulation for yam production on the oxysols of Cameroon is another constraint. This study was aimed at enhancing the availability of quality seeds through the characterization of five yam accessions. One experiment was performed to determine the effect of cultivar and origin of tuber sets on their germination rate. The <span>second concerned the evaluation of cultivars and soil treatment effects on ag</span>ronomic parameters of yam seedlings. Yam cultivars were subjected to nine fertilizer formulations as follows: T0: no fertilizer;T1: mycorrhizal fungi (MF) + 150 g manure + peanut waste;T2: 25 g chemical fertilizer (20.10.10);T3: MF + peanut waste;T4: 16 g chemical fertilizer (12.6.20);T5: 25 g (20.10.10) +100 g CaO + 150 g manure;T6: 100 g CaO + 150 g manure;T7: 20 g tropicote + 2 g DAP (Diammonium phosphate, a reference starter fertilizer coded N18P46) + 100 g CaO + 150 g manure;and T8: mycorrhiza. These treatments were tested in a factorial design. Results show that Ibo sweet 3 and Mabondji sweet white 1 yam accessions were less affected by anthracnose disease on the aerial parts. Guzang 1 showed the best germination rate and yield, making it appropriate for cultivation in the region. Soil treatments, T2, T5, T7 and T8 significantly increased the yield of yam cultivars. Mycorrhiza treatment alone gave a better response to seed weight, indicating the interest of this biofertilizer as a solution for good seedling production. These fertilizer treatments can be recommended to farmers for more seed production with optimum seed weight (300 g).
基金funded by National Key Research and Development Program of China(No.2022YFE0116300)National Natural Science Foundation of China(4217070510).
文摘Soil acidification negatively affects plant growth,soil microbial composition and diversity,and the sustainability of agricultural ecosystems.The primary sources of soil acidity include base cations(BCs)leaching loss,the weathering of aluminum-containing minerals,excess cation uptake by plants,and the transformation of nitrogen,carbon,and sulfur compounds by soil microorganisms.Soil acidity reflects the degree of soil acidification and is characterized by the active acidity(intensity factor)and exchangeable acidity(quantity factor),while soil acid buffering capacity(Acid-BC)(capacity factor)controls the degree and rate of soil acidification.Biochar,as an alkaline,porous and carbonrich matter,not only reduces soil active and exchangeable acidity but also enhances the Acid-BC.Having a variety of BCs and oxygen-containing functional groups(OFGs),biochar improves acidic soil mainly through liming effect,cation exchange,complexation,and precipitation reactions.Thus,to improve acidic soils,the application of biochar may be a better alternative than conventional liming materials.However,further studies into re-acidification of biochar-amended soil due to biochar aging,nitrification of excess fertilizer nitrogen and their interaction are still required by binding the mechanistic comprehension of biochar-to-soil interactions and prolonged field researches.
基金supported by the earmarked fund for the Modern Agro-Industry Technology Research System (No.CARS-19)the Innovative Research Team in Chinese Academy of Agricultural Sciences (No.CAAS ASTIP-2014-TRICAAS).
文摘Pyrrolizidine alkaloids(PAs)and their N-oxides(PANOs)are phytotoxins produced by various plant species and have been emerged as environmental pollutants.The sorption/desorption behaviors of PAs/PANOs in soil are crucial due to the horizontal transfer of these natural products from PA-producing plants to soil and subsequently absorbed by plant roots.This study firstly investigated the sorption/desorption behaviors of PAs/PANOs in tea plantation soils with distinct characteristics.Sorption amounts for seneciphylline(Sp)and seneciphylline-N-oxide(SpNO)in three acidic soils ranged from 2.9 to 5.9μg/g and 1.7 to 2.8μg/g,respectively.Desorption percentages for Sp and SpNO were from 22.2%to 30.5%and 36.1%to 43.9%.In the mixed PAs/PANOs systems,stronger sorption of PAs over PANOs was occurred in tested soils.Additionally,the Freundlich models more precisely described the sorption/desorption isotherms.Cation exchange capacity,sand content and total nitrogen were identified as major influencing factors by linear regression models.Overall,the soils exhibiting higher sorption capacities for compounds with greater hydrophobicity.PANOs were more likely to migrate within soils and be absorbed by tea plants.It contributes to the understanding of environmental fate of PAs/PANOs in tea plantations and provides basic data and clues for the development of PAs/PANOs reduction technology.
基金financially supported by the Key project of National Natural Science Foundation of China(42230711).
文摘The widespread occurrence of acidic soils presents a major challenge for agriculture,as it hampers productivity via a combination of mineral toxicity,nutrient deficiency,and poor water uptake.Conventional remediation methods,such as amending the soil with lime,magnesium,or calcium,are expensive and not environmentally friendly.The most effective method to mitigate soil acidity is the cultivation of acid-tolerant cultivars.The ability of plants to tolerate acidic soils varies significantly,and a key factor influencing this tolerance is aluminum(Al)toxicity.Therefore,understanding the physiological,molecular,and genetic underpinnings of Al tolerance is essential for the successful breeding of acid-tolerant crops.Different tolerance mechanisms are regulated by various genes and quantitative trait loci in various plant species,and molecular markers have been developed to facilitate gene cloning and to support marker-assisted selection for breeding Al-tolerant cultivars.This study provides a comprehensive review of the current developments in understanding the physiological and molecular mechanisms underlying Al resistance.Through the application of genome-wide association methods,it is expected that new Al-resistant genes can be identified and utilized to cultivate Al-resistant varieties through intercrossing,backcrossing,and molecular marker-assisted selection,promoting the sustainable use of acidic soils.
基金Supported by Science and Technology Program Major Project of Yunnan Branch,China National Tobacco Corporation(2020530000241022)。
文摘[Objectives]This study was conducted to improve acidic soil and enhance the quality of tobacco leaves.[Methods]The effects of different microbial fertilizers on improving acidic tobacco-planting soil and tobacco leaf quality were investigated through plot experiments.[Results]The application of microbial fertilizers could improve the pH value of acidic soil,and composite microbial agent A showed the best application effect.The application of bio-organic fertilizer was beneficial to improving the contents of available phosphorus and available boron in acidic soil.The application of composite microbial agent A was beneficial to improving the contents of available phosphorus and available potassium in acidic soil,and could promote the growth of tobacco plants and improve the economic traits of flue-cured tobacco and the coordination of chemical components in tobacco leaves.The application of composite microbial agent B led to a downward trend in the content of available boron in acidic soil.The application of composite microbial agent B could promote the absorption of nutrients by tobacco plants,and improve their disease resistance and the quality of tobacco leaves.Due to the differences in functional microorganisms contained,the application effects of different microbial fertilizers in improving acidic tobacco-planting soil and improving tobacco leaf quality varied.Overall,the application of microbial fertilizers could increase soil pH,activate soil nutrients,promote tobacco growth,enhance disease resistance,increase tobacco output value,and improve tobacco quality.Microbial fertilizers have good application prospects in improving acidic soil and improving tobacco quality.[Conclusions]The application of microbial fertilizers to improve acidic tobacco-planting soil can ensure the normal growth and development of tobacco plants and the improvement of tobacco leaf quality,achieving high-quality and sustainable development of Zhaotong tobacco.
基金Project supported by the Potash & Phosphate Institute/Potash & Phosphate Institute of Canada (PPI/PPIC) (No. Chongqing-02).
文摘Nutrient limiting factors in acidic soils from vegetable fields of the Chongqing suburbs of China were assessed by employing the systematic approach developed by Agro Services International (ASI) including soil testing, nutrient adsorption study, and pot and field experiments to verify the results of soil testing, with a conventional soil test (CST) used for comparison. The ASI method found the moderately acidic soil (W01) to be N and P deficient; the strongly acidic soil (W04) to be N, K and S deficient; and the slightly acidic soil (W09) to be N, K, S, Cu, Mn, and Zn deficient. The CST method showed that W01 had P, B and Cu deficiencies; W04 had N, P and S deficiencies; and W09 had N, P, S, B, Cu, and Zn deficiencies. There were differences between the two methods. Among the two indicator plants selected, the response of sorghum on the three representative acidic soils was more closely related to the ASI results than that of sweet pepper.
基金financially supported by the National Natural Science Foundation of China(No.41271267)
文摘The occurrence of nitri?cation in some acidic forest soils is still a subject of debate.Identi?cation of main nitri?cation pathways in acidic forest soils is still largely unknown.Acidic yellow soil(Oxisol) samples were selected to test whether nitri?cation can occur or not in acidic subtropical pine forest ecosystems.Relative contributions of autotrophs and heterotrophs to nitri?cation were studied by adding selective nitri?cation inhibitor nitrapyrin.Soil NH^+_4-N concentrations decreased,but NO^-_3-N concentrations increased signi?cantly for the no-nitrapyrin control during the ?rst week of incubation,indicating that nitri?cation did occur in the acidic subtropical soil.The calculated net nitri?cation rate was 0.49 mg N kg^(-1)d^(-1)for the no-nitrapyrin control during the ?rst week of incubation.Nitrapyrin amendment resulted in a signi?cant reduction of NO^-_3-N concentration.Autotrophic nitri?cation rate averaged0.28 mg N kg^(-1)d^(-1)and the heterotrophic nitri?cation rate was 0.21 mg N kg^(-1)d^(-1)in the ?rst week.Ammonia-oxidizing bacteria(AOB) abundance increased slightly during incubation,but nitrapyrin amendment signi?cantly decreased AOB amo A gene copy numbers by about 80%.However,the ammonia-oxidizing archaea(AOA) abundance showed signi?cant increases only in the last 2weeks of incubation and it was also decreased by nitrapyrin amendment.Our results indicated that nitri?cation did occur in the present acidic subtropical pine forest soil,and autotrophic nitri?cation was the main nitri?cation pathway.Both AOA and AOB were the active biotic agents responsible for autotrophic nitri?cation in the acidic subtropical pine forest soil.
基金the Joint Fund of Natural Science Foundation of Liaoning Province(Grant No.2020-HYLH-14)the Natural Science Foundation of Liaoning Province(2022-MS-362)。
文摘Electrochemical experiments,slow strain rate tensile testing(SSRT),and scanning electron microscopy were used to investigate the effect of various applied potentials on the stress corrosion cracking(SCC)of X80 pipeline steel in acidic soil containing sulfate-reducing bacteria(SRB).The results demonstrated that when the anodic potential was applied,X80 steel exhibited sensitivity to SCC,which was attributed to anodic dissolution.The SCC sensitivity initially decreased,but then increased with a negative shift in the applied potential.At-1200 mV,SCC was the most sensitive,which corresponded to the substantial cathodic polarisation and toxic impact of SRB,which increased the risk of hydrogen embrittlement.At-850 mV,the SCC sensitivity was the lowest because cathodic polarisation suppressed anodic dissolution.The experimental results can contribute to the prevention and management of SCC in operational pipelines.
基金Supported by General Project of Chongqing Technology Innovation and Application Demonstration(Social People s Livelihood Category)(cstc2018jscx-msybX0215)Horizontal Project of Chongqing Agricultural Technology Extension Station(WLHX-2021-0113).
文摘[Objectives]This study was conducted to investigate the effects of biochar-based fertilizer on high yield and quality of green pepper(Zanthoxylum armatum var.novemfolius)and soil nutrient status.[Methods]With green pepper and pepper field soil as the research subjects,four treatments were set up,namely,conventional fertilization(T_(1)),conventional fertilization+biochar(T_(2)),biochar-based fertilizer 1(T_(3)),and biochar-based fertilizer 2(T_(4)).[Results]The application of biochar-based fertilizer increased green pepper yield by 9.37%-51.12%,with the order of increase being T_(4)>T_(3)>T_(2)>T_(1).In terms of soil nutrients,biochar-based fertilizer raised soil pH by 6.67%-53.33%,with the order of increase being T_(3)>T_(4)>T_(2)>T_(1).The initially strongly acidic soil gradually shifted to weakly acidic and approached neutral,indicating significantly improved soil acidity.The application of biochar-based fertilizer increased the contents of soil organic matter,available nitrogen,available phosphorus,available potassium,available copper,available zinc,available iron,and available manganese.It significantly enhanced green pepper yield,improved soil acidity,and elevated soil nutrient levels.Considering yield,nutrient uptake,and soil nutrient content,biochar-based fertilizer 2(T_(4))was identified as the optimal treatment.[Conclusions]This study provides a theoretical basis for improving green pepper yield and soil amendment.
基金supported by the National Key Basic Research Program of China(No.2014CB441003)the National Key Research and Development of China(No.2016YFD0200302)
文摘The chemical characteristics,element contents,mineral compositions,and the ameliorative effects on acid soils of five biomass ashes from different materials were analyzed. The chemical properties of the ashes varied depending on the source biomass material. An increase in the concrete shuttering contents in the biomass materials led to higher alkalinity,and higher Ca and Mg levels in biomass ashes,which made them particularly good at ameliorating effects on soil acidity. However,heavy metal contents,such as Cr,Cu,and Zn in the ashes,were relatively high. The incorporation of all ashes increased soil p H,exchangeable base cations,and available phosphorus,but decreased soil exchangeable acidity. The application of the ashes from biomass materials with a high concrete shuttering content increased the soil available heavy metal contents. Therefore,the biomass ashes from wood and crop residues with low concrete contents were the better acid soil amendments.
基金Supported by National Natural Science Foundation of China(31201688)Yunnan University’s Research Innovation Fund for Graduate Students
文摘This study was conducted to investigate the effects of mixed biochar on the nitrification rate in acidic soils. A15 N tracer experiment with(15 NH4)2 SO4 was conducted to determine the nitrification rates of 4 acidic agricultural soils with p H 4.03-6.02 in Yunnan Province, Southern China. The accumulation of15 N-NO3-and nitrification rates decreased with the addition of biochar at the end of incubation, suggesting that biochar could be a nitrification inhibitor in acidic fertilized soil. Nitrification rates in soil with p H 4.03 were evidently lower than those in soil with p H 4.81-6.02 with or without biochar. Decreased nitrification rates were detected in the acidic soils with biochar. Soil p H controlled nitrification more than biochar in certain strongly acidic soils.
