Background: To our knowledge, there is little study on the interaction between nutrient availability and molecular structure changes induced by different processing methods in dairy cattle. The objective of this study...Background: To our knowledge, there is little study on the interaction between nutrient availability and molecular structure changes induced by different processing methods in dairy cattle. The objective of this study was to investigate the effect of heat processing methods on interaction between nutrient availability and molecular structure in terms of functional groups that are related to protein and starch inherent structure of oat grains with two continued years and three replication of each year.Method: The oat grains were kept as raw(control) or heated in an air-draft oven(dry roasting: DO) at 120 °C for 60 min and under microwave irradiation(MIO) for 6 min. The molecular structure features were revealed by vibrational infrared molecular spectroscopy.Results: The results showed that rumen degradability of dry matter, protein and starch was significantly lower(P <0.05) for MIO compared to control and DO treatments. A higher protein α-helix to β-sheet and a lower amide I to starch area ratio were observed for MIO compared to DO and/or raw treatment. A negative correlation(-0.99, P < 0.01)was observed between α-helix or amide I to starch area ratio and dry matter. A positive correlation(0.99, P < 0.01) was found between protein β-sheet and crude protein.Conclusion: The results reveal that oat grains are more sensitive to microwave irradiation than dry heating in terms of protein and starch molecular profile and nutrient availability in ruminants.展开更多
In order to reveal the mechanism of silicon(Si)fertilizer in improving nitrogen(N)and phosphorus(P)nutrient availability in paddy soil,we designed a series of soil culture experiments by combining application of varyi...In order to reveal the mechanism of silicon(Si)fertilizer in improving nitrogen(N)and phosphorus(P)nutrient availability in paddy soil,we designed a series of soil culture experiments by combining application of varying Si fertilizer concentrations with fixed N and P fertilizer concentrations.Following the recommendations of fertilizer manufacturers and local farmers,we applied Si in concentrations of 0,5.2,10.4,15.6,and 20.8μg/kg.At each concentration of added Si,the availability of soil N and P nutrients,soil microbial activity,numbers of ammonia-oxidizing bacteria and P-decomposing bacteria which means that the organic P is decomposed into inorganic nutrients which can be absorbed and utilized by plants,and urease and phosphatase activity first increased,and then decreased,as Si was added to the soil.These indicators reached their highest levels with a Si application rate of 15.6μg/kg,showing values respectively 19.78%,105.09%,8.34%,73.12%,130.36%,28.12%,and 20.15%higher than those of the controls.Appropriate Si application(10.4 to 15.6µg/kg)could significantly increase the richness of the soil microbial community involved in cycling of N and P nutrients in the soil.When the Si application rate was 15.6μg/kg,parameters for characterizing microbial abundance such as sequence numbers,operational taxonomic unit(OTU)number,and correlation indices of microbial community richness such as Chao1 index,the adaptive coherence estimator(ACE)index,Shannon index,and Simpson index all reached maximum values,with amounts increased by 14.46%,10.01%,23.80%,30.54%,0.18%,and 2.64%,respectively,compared with the control group.There is also a good correlation between N and P mineralization and addition of Si fertilizer.The correlation coefficients between the ratio of available P/total P(AP/TP)and the number of ammonia-oxidizing bacteria,AP/TP and acid phosphatase activity(AcPA),AP/TP and the Shannon index,the ratio of available N/total amount of N(AN/TN)and the number of ammoniated bacteria,and AN/TN and AcPA were 0.9290,0.9508,0.9202,0.9140,and 0.9366,respectively.In summary,these results revealed that enhancement of soil microbial community structure diversity and soil microbial activity by appropriate application of Si is the key ecological mechanism by which application of Si fertilizer improves N and P nutrient availability.展开更多
In spite of the relevance of current studies on the importance of organic fertilizers such as animal manure in improving the health of ecosystems, little is known about the biochemical mechanisms affecting the availab...In spite of the relevance of current studies on the importance of organic fertilizers such as animal manure in improving the health of ecosystems, little is known about the biochemical mechanisms affecting the availability of nutrients released from the organic fertilizer in water. A litter bag study during 6 weeks was carried out in pots containing 25 liters of water with 15 g of pig dejections as organic fertilizers. The experimental design was a completely randomized block design with three replications. The treatments consisted of dejections of pigs nourished with: recommended diet composition T1, partially improved diet with Azolla filiculoides T2, improved diet with Azolla filiculoides T3, improved diet with cereal bran T4. A control treatment without dejection (T0) was considered in the study for comparison purpose. Four pigs per type of diet were considered leading to 16 white landrace pigs of six months age followed for dejection collections. Strong release of nutrients for better yield for agro-fish system was obtained in the manure T1 with ??(10.85 ± 0.00) mg/L;?( 0.011 ± 0.00) mg/L;?(2.13 ± 0.07) mg/L and K+ (10.76 ± 0.57) mg/L;Ca2+ (2.92 ± 0.11) mg/L and Mg2+ (2.53 ± 0.00) mg/L followed by manure T3 and T4 with high N content. The relatively low ratio C/N (14.25) for T1 and (15.84) for T3 induced more nutrients releasing. This study showed an important N loss probably due to microorganism activities which fluctuate nutrient availability. Also significant correlations were noted between the nutrient dynamics in water and physicochemical parameters showing the effect of abiotic factors on organic matter decomposition and mineralization which depend on microbial activities in water and pig manure composition.展开更多
[Objectives] This study was conducted to explore the differences in soil nutrient contents of cultivated land in different regions of Laos,and to provide a basis for soil nutrient management and scientific fertilizati...[Objectives] This study was conducted to explore the differences in soil nutrient contents of cultivated land in different regions of Laos,and to provide a basis for soil nutrient management and scientific fertilization in Laos. [Methods] By collecting 166 samples of the 0-20 cm cultivated soil layer from farmland in the farming areas of Luang Namtha Province in the northern part of Laos and Vientiane Province in the middle of the country,the contents of soil organic matter,total nitrogen,available phosphorus,available potassium,available calcium and available magnesium were analyzed,so as to evaluate the current status of soil nutrient fertility and explore the differences in soil nutrient contents of regional cultivated land. [Results] The soil organic matter was relatively abundant,the total nitrogen and available potassium contents were at the lower-middle level,and the available phosphorus,available calcium and available magnesium were insufficient or extremely insufficient. The soil nutrient contents of cultivated land were different in different regions. [Conclusions] It is suggested that lime or other alkaline fertilizers should be applied on the farmland with acid soil,and nitrogen,phosphorus,and potassium fertilizers should be added at the same time to improve soil nutrient fertility.展开更多
[Objectives]This study was conducted to investigate the variation characteristics of soil nutrient contents under different land use patterns in the middle and upper reaches of the Niyang River in Tibet.[Methods]With ...[Objectives]This study was conducted to investigate the variation characteristics of soil nutrient contents under different land use patterns in the middle and upper reaches of the Niyang River in Tibet.[Methods]With the cultivated land,grass land and forest land in the middle and upper reaches of the Niyang River as the research objects,216 soil samples were collected in layers(0-10,10-20,20-30 cm)by the standard sampling method,and the soil total nitrogen,alkali-hydrolyzable nitrogen,total potassium,available potassium,total phosphorus,available phosphorus and organic matter were determined.[Results]The contents of soil organic matter,total nitrogen and alkali-hydrolyzable nitrogen in the middle and upper reaches of Niyang River in Tibet ranked as forest land>grass land>cultivated land,and there were significant differences between the three(P<0.05).The total potassium contents of grass land and forest land were not much different,and the contents of available potassium exhibited an order of forest land>grass land>cultivated land.The distribution of soil total nutrients and available nutrients under different land use patterns showed a certain degree of surface aggregation.The contents of total nutrients and available nutrients in the soil at the 0-10 cm depth were significantly higher than those at 10-20 and 20-30 cm,and there were significant differences between the three(P<0.05).The average content of alkali-hydrolyzable nitrogen was the largest in forest soil and the smallest in cultivated land under the three land use patterns in the study area.The average content of soil available phosphorus in cultivated land(19.47 mg/kg)was significantly higher than those in grass land(5.73 mg/kg)and forest land(5.19 mg/kg).The above results indicate that long-term vegetation restoration can improve the soil quality of the middle and upper reaches of the Niyang River.[Conclusions]The results of this study research provide basic support for improving the soil effect in the area.展开更多
Biochar application is claimed to improve nutrient availability in many problem soils;however, pristine biochars are often reported to produce inconsistent results. Therefore, appropriate biochar modification techniqu...Biochar application is claimed to improve nutrient availability in many problem soils;however, pristine biochars are often reported to produce inconsistent results. Therefore, appropriate biochar modification techniques are required to retain soil nutrients at an optimum level. To increase Nitrogen (N) and Phosphorus (P) availability in coastal saline soil, two slow pyrolyzed biochars viz domestic organic waste (DWB) and farmyard manure (FMB) were modified with MgCl<sub>2</sub>. Ten different treatments comprising the biochars (pristine and modified) with and without the recommended fertilizer were applied (2% w/w) to the soil and incubated for ninety days. The soils were analyzed for pH, EC, available <img src="Edit_0d6ce0cb-4936-4874-a480-35d5b2f585ff.png" alt="" />, <img src="Edit_64cd5bd3-ddeb-4e08-ad2e-48f0710feace.png" alt="" /> and different phosphorus fractions sequentially extracted by NH<sub>4</sub>Cl, NaHCO<sub>3</sub>, NaOH, and HCl. During the incubation period, biochar treatments increased all phosphorus and nitrogen fractions than the control and recommended fertilizer treatment. The application of FMB significantly (<em>p</em> < 0.05) increased NH<sub>4</sub>Cl, NaHCO<sub>3</sub>, and NaOH extractable P fractions from DWB, while HCl soluble fraction was enhanced (<em>p</em> > 0.05) by DWB. The increased Al and/or Fe bound phosphate after 60 days of incubation had significant correlations to decreasing soil pH and NaHCO<sub>3</sub>-P, indicating reduced availability with time. Further Mg modification slightly increased P availability only after 60 days of incubation. The modification also improved both nitrogen fractions but significantly (<em>p</em> < 0.05) increased the NO<sub>3</sub>-N content which could be the result of electrostatic attraction between Mg<sup>2</sup>+ and <img src="Edit_c55861ac-dd25-4c26-9ecc-2e134a948b8e.png" alt="" /> ions. Overall, Mg-modified biochar may retain both phosphates and nitrates in soil. However, the magnitude of retention will vary depending on biochar type, nutrient species, and aging in soil.展开更多
Inoculation of alfalfa seedlings with root growth promoting microorganisms under semi-arid climate condition may improve biomass production and nutritive value.The current study aimed to investigate the effect of inoc...Inoculation of alfalfa seedlings with root growth promoting microorganisms under semi-arid climate condition may improve biomass production and nutritive value.The current study aimed to investigate the effect of inoculation of alfalfa seedlings with Piriformospora indica(Pi) and co-inoculating Pi with Glomus intraradices(Gi+Pi) or Sinorhizobium meliloti(Sm+Pi) on hay yield,chemical composition,molecular structures by Fourier transformed infrared(FTIR) spectroscopy,in situ ruminal degradability and in vitro gas production.Seedlings were grown in experimental pots in a greenhouse until first cut and then transferred outside and cut a further 4 times.Biomass yield was similar across the treatments.Acid detergent fiber(ADF) concentration was higher in Pi than in control hay,and ADF decreased further with co-inoculation(P < 0.05).The ether extract(EE) concentration was lower for Pi and Gi+Pi compared with control hay,and control,Pi and Gi+Pi hays had lower EE concentration compared with Sm+Pi(P < 0.05).The FTIR spectroscopic vibration peak height ratio related to proteins(amide1+amide 2): total carbohydrate ratio was lower for the inoculation treatments compared with control hay(P < 0.05).In situ ruminal degradability of dry matter and organic matter were higher for hay of inoculated and co-inoculated seedlings than for control hay(P < 0.05).In conclusion,hay of alfalfa seedlings inoculated and co-inoculated with root growth promoting microorganisms had improved nutritional value compared with hay from non-treated alfalfa seedlings,and co-inoculation was the most effective,however,changes were relatively minor.展开更多
Forest fires are key ecosystem modifiers affecting the biological,chemical,and physical attributes of forest soils.The extent of soil disturbance by fire is largely dependent on fire intensity,duration and recurrence,...Forest fires are key ecosystem modifiers affecting the biological,chemical,and physical attributes of forest soils.The extent of soil disturbance by fire is largely dependent on fire intensity,duration and recurrence,fuel load,and soil characteristics.The impact on soil properties is intricate,yielding different results based on these factors.This paper reviews research investigating the effects of wildfire and prescribed fire on the biological and physico-chemical attributes of forest soils and provides a summary of current knowledge associated with the benefits and disadvantages of such fires.Low-intensity fires with ash deposition on soil surfaces cause changes in soil chemistry,including increase in available nutrients and pH.High intensity fires are noted for the complete combustion of organic matter and result in severe negative impacts on forest soils.High intensity fires result in nutrient volatilization,the break down in soil aggregate stability,an increase soil bulk density,an increase in the hydrophobicity of soil particles leading to decreased water infiltration with increased erosion and destroy soil biota.High soil heating(> 120℃) from high-intensity forest fires is detrimental to the soil ecosystem,especially its physical and biological properties.In this regard,the use of prescribed burning as a management tool to reduce the fuel load is highly recommended due to its low intensity and limited soil heating.Furthermore,the use of prescribed fires to manage fuel loads is critically needed in the light of current global warming as it will help prevent increased wildfire incidences.This review provides information on the impact of forest fires on soil properties,a key feature in the maintenance of healthy ecosystems.In addition,the review should prompt comprehensive soil and forest management regimes to limit soil disturbance and restore fire-disturbed soil ecosystems.展开更多
Aims Conversion of secondary forests to pure larch plantations is a common management practice driven by the increasing demand for timber production in Northeast China,resulting in a reduction in soil nutrient availab...Aims Conversion of secondary forests to pure larch plantations is a common management practice driven by the increasing demand for timber production in Northeast China,resulting in a reduction in soil nutrient availability after a certain number of years following conversion.Nutrient resorption prior to leaf senescence was related to soil fertility,an important nutrient conservation strategy for plants,being especially significant in nutrient-poor habitats.However,the seasonal dynamics of leaf nutrients and nutrient resorption in response to secondary forest conversion to larch plantations is not well understood.Methods A comparative experiment between larch plantations(Larix spp.)and adjacent secondary forests(dominant tree species including Quercus mongolica,Acer mono,Juglans mandshurica and Fraxinus rhynchophylla)was conducted.We examined the variations in leaf nutrient(macronutrients:N,P,K,Ca and Mg;micronutrients:Cu and Zn)concentrations of these tree species during the growing season from May to October in 2013.Nutrient resorption efficiency and proficiency were compared between Larix spp.and the broadleaved species in the secondary forests.Important Findings Results show that the seasonal variation of nutrient concentrations in leaves generally exhibited two trends,one was a downward trend for N,P,K,Cu and Zn,and another was an upward trend for Ca and Mg.The variations in foliar nutrient concentrations were mainly controlled by the developmental stage of leaves rather than by tree species.Resorption of the observed seven elements varied among the five tree species during leaf senescence.Nutrient resorption efficiency varied 6–75%of N,P,K,Mg,Cu and Zn,while Ca was not retranslocated in the senescing leaves of all species,and Mg was not retranslocated in Larix spp.Generally,Larix spp.tended to be more efficient and proficient(higher than 6–30%and 2–271%of nutrient resorption efficiency and resorption proficiency,respectively)in resorbing nutrients than the broadleaved species in the secondary forests,indicating that larch plantations had higher leaf nutrient resorption and thus nutrient use efficiency.Compared with Larix spp.,more nutrients would remain in the leaf litter of the secondary forests,indicating an advantage of secondary forests in sustaining soil fertility.In contrast,the larch plantation would reuse internal nutrients rather than lose nutrients with litter fall and thus produce a positive feedback to soil nutrient availability.In summary,our results suggest that conversion from secondary forests to pure larch plantations would alter nutrient cycling through a plantmediated pathway.展开更多
Biochars,when applied to contaminated solutions or soils,may sequester potentially toxic elements while releasing neces-sary plant nutrients.This purpose of this study focused on quantifying both phenomenon following ...Biochars,when applied to contaminated solutions or soils,may sequester potentially toxic elements while releasing neces-sary plant nutrients.This purpose of this study focused on quantifying both phenomenon following wheat straw(Triticum aestivum L.)biochar application(0,5,and 15%by wt)to a Cd containing solution and a Cd-contaminated paddy soil using 240-day laboratory batch experiments.Following both experiments,solid phases were analyzed for elemental associations using a combination of wet chemical sequential extractions and synchrotron-based X-ray absorption spectroscopy(XAS).When wheat straw biochar was applied at 15%to Cd containing solutions,Cd and Zn concentrations decreased to below detection in some instances,Ca and Mg concentrations increased by up to 290%,and solution pH increased as compared to the 5%biochar application rate.Similar responses were observed when biochar was added to the Cd-contaminated paddy soil,suggesting that this particular biochar has the ability to sequester potentially toxic elements while releasing necessary plant nutrients to the soil solution.When significant,positive correlations existed between nutrient release over time,while negative correlations were present between biochar application rate,potentially toxic element sorption and pH.The latter suggests that potentially toxic elements were sorbed by a combination of organic functional groups or mineral precipitation based on whether pH was above or below~7.In support of this contention,the wet chemical sequential extraction procedure in conjunction with previously observed Cd or current Zn XAS showed that biochar application promoted the formation of layered double hydroxides,sorption to(oxy)hydroxides,and organically bound to biochar as Zn species.As a multi-functional material,biochar appears to play an important role in sequestering Cd while releasing essential plant nutrients.These findings suggest that biochar may be a‘win-win’for improving environmental quality in potentially toxic element contaminated agroecosystems.展开更多
Foliar nutrient resorption(NuR)plays a key role in ecosystem functioning and plant nutrient economy.Most of this recycling occurs during the senescence of leaves and is actively addressed by cells.Here,we discuss the ...Foliar nutrient resorption(NuR)plays a key role in ecosystem functioning and plant nutrient economy.Most of this recycling occurs during the senescence of leaves and is actively addressed by cells.Here,we discuss the importance of cell biochemistry,physiology,and subcellular anatomy to condition the outcome of NuR at the cellular level and to explain the existence of limits to NuR.Nutrients are transferred from the leaf in simple metabolites that can be loaded into the phloem.Proteolysis is the main mechanism for mobilization of N,whereas P mobilization requires the involvement of different catabolic pathways,making the dynamics of P in leaves more variable than those of N before,during,and after foliar senescence.The biochemistry and fate of organelles during senescence impose constraints that limit NuR.The efficiency of NuR decreases,especially in evergreen species,as soil fertility increases,which is attributed to the relative costs of nutrient acquisition from soil decreasing with increasing soil nutrient availability,while the energetic costs of NuR from senescing leaves remain constant.NuR is genetically determined,with substantial interspecific variability,and is environmentally regulated in space and time,with nutrient availability being a key driver of intraspecific variability in NuR.展开更多
Dysregulation of metabolism allows tumor cells to generate needed building blocks as well as to modulate epigenetic marks to support cancer initiation and progression.Cancer-induced metabolic changes alter the epigene...Dysregulation of metabolism allows tumor cells to generate needed building blocks as well as to modulate epigenetic marks to support cancer initiation and progression.Cancer-induced metabolic changes alter the epigenetic landscape,especially modifications on histones and DNA,thereby promoting malignant transformation,adaptation to inadequate nutrition,and metastasis.Recent advances in cancer metabolism shed light on how aberrations in metabolites and metabolic enzymes modify epigenetic programs.The metabolism-induced recoding of epigenetics in cancer depends strongly on nutrient availability for tumor cells.In this review,we focus on metabolic remodeling of epigenetics in cancer and examine potential mechanisms by which cancer cells integrate nutritional inputs into epigenetic modification.展开更多
Microbial carbon use efficiency(CUE)is an important factor driving soil carbon(C)dynamics.However,microbial CUE could positively,negatively,or neutrally respond to increased temperature,which limits our prediction of ...Microbial carbon use efficiency(CUE)is an important factor driving soil carbon(C)dynamics.However,microbial CUE could positively,negatively,or neutrally respond to increased temperature,which limits our prediction of soil C storage under future climate warming.Experimental warming affects plant production and microbial communities,which thus can have a significant impact on biogeochemical cycles of terrestrial ecosystems.Here,we reviewed the present research status of methods measuring microbial CUE and the response of microbial CUE to the changes of biotic and abiotic factors induced by warming.Overall,current measurement methods mainly include metabolic flux analysis,calorespirometry,stoichiometric model,13C and 18O labeling.Differences in added substrate types can lead to an overestimation or underestimation on microbial CUE,particularly when using the 13C labeling method.In addition,changes in the dominant microbial community under warming may also affect CUE.However,there is still uncertainty in CUE characteristics of different microorganisms.Microbial CUE is generally decreased under warming conditions as microbes are subjected to water stress or soil labile organic matter is much more depleted compared to ambient conditions.In contrast,considering that warming increases soil nutrient availability,warming may enhance microbial CUE by alleviating nutrient limitations for microbes.In conclusion,the response of microbial CUE to warming is more complex than expected.The microbial growth and physiological adaptation to environmental stress under warming is one of the main reasons for the inconsistence in microbial CUE response.Finally,we propose five aspects where further research could improve the understanding of microbial CUE in a warmer world,including using new technologies,establishing multi-factor interactive experiments,building a network of experimental research platform for warming,and strengthening studies on response of CUE to warming at different soil depths and on different temporal scales.展开更多
Legume plants are an essential component of sustainable farming systems.Phosphorus(P) deficiency is a significant constraint for legume production, especially in nutrient-poor soils of arid and semi-arid regions.In th...Legume plants are an essential component of sustainable farming systems.Phosphorus(P) deficiency is a significant constraint for legume production, especially in nutrient-poor soils of arid and semi-arid regions.In the present study, we conducted a pot experiment to evaluate the effects of a phosphorus-mobilizing plant-growth promoting rhizobacterial strain Bacillus cereus GS6, either alone or combined with phosphate-enriched compost(PEC) on the symbiotic(nodulation-N_2 fixation) performance of soybean(Glycine max(L.) Merr.) on an Aridisol.The PEC was produced by composting food waste with addition of single super phosphate.The bacterial strain B.cereus GS6 showed considerable potential for P solubilization and mobilization by releasing carboxylates in insoluble P(rock phosphate)-enriched medium.Inoculation of B.cereus GS6 in combination with PEC application significantly improved nodulation and nodule N_2 fixation efficiency.Compared to the control(without B.cereus GS6 and PEC), the combined application of B.cereus GS6 with PEC resulted in significantly higher accumulation of nitrogen(N), P, and potassium(K) in grain, shoot, and nodule.The N:P and P:K ratios in nodules were significantly altered by the application of PEC and B.cereus GS6, which reflected the important roles of P and K in symbiotic performance of soybean.The combined application of PEC and B.cereus GS6 also significantly increased the soil dehydrogenase and phosphomonoesterase activities, as well as the soil available N, P, and K contents.Significant positive relationships were found between soil organic carbon(C) content, dehydrogenase and phosphomonoesterase activities, and available N, P, and K contents.This study suggests that inoculation of P-mobilizing rhizobacteria, such as B.cereus GS6, in combination with PEC application might enhance legume productivity by improving nodulation and nodule N_2 fixation efficiency.展开更多
Aims Changes in the phenotype of crops(phenotypic plasticity)are known to play an important role in determining responses to nutrient availability,with the direction and magnitude of plasticity of individual traits be...Aims Changes in the phenotype of crops(phenotypic plasticity)are known to play an important role in determining responses to nutrient availability,with the direction and magnitude of plasticity of individual traits being crucial for grain yields.Our study analysed the direction,magnitude and hierarchy of plastic responses of yieldrelated traits(i.e.biomass allocation and yield components)of rice(Oryza sativa L.)to nutrient availability.We estimated the effect of inoculation with arbuscular mycorrhizal fungi(AMF)on these characteristics of phenotypic plasticity.Methods A field experiment was carried out in northeast China,providing rice with six NPK fertilizer levels with or without inoculation with Glomus mosseae.At maturity,we quantified biomass allocation traits(shoot:root ratio and panicle:shoot ratio)and yield component traits(panicle number per hill,spikelet number per panicle,percentage of filled spikelets and seed weight).We also assessed the direction of change in each trait and the magnitude of trait plasticity.Important Findings In non-inoculated plants,we found that biomass allocation and seed-number traits(i.e.panicle number per hill,spikelet number per panicle and percentage of filled spikelets)responded to fertilization in the same direction,increasing with rising fertilization.Panicle formation was the most plastic trait,while seed mass was the least plastic trait.AMF inoculation nullified the relationship between most biomass allocation and seed-number traits(except for that between panicle:shoot ratio and the percentage of filled spikelets)but increased the magnitude of plasticity in biomass allocation traits without altering the hierarchy of traits’plasticity.These results underscore the importance of plasticity of yield-related traits per se,and the impact of AMF on plasticity,for maintaining rice yields under low fertilization regimes.展开更多
The hydrothermal carbonization(HTC)of biogas digestate alters the raw materials inherent characteristics to produce a carbon(C)-rich hydrochar(HC),with an improved suitability for soil amelioration.Numerous studies re...The hydrothermal carbonization(HTC)of biogas digestate alters the raw materials inherent characteristics to produce a carbon(C)-rich hydrochar(HC),with an improved suitability for soil amelioration.Numerous studies report conflicting impacts of various HC application rates on soil properties and plant growth.In this study,the influence of HC application rate on soil improvement and plant growth aspects was investigated in three diverse soils(Chernozem,Podzol,and Gleysol).Pot trials were conducted in which all soils were amended with 5,10,20 and 30%(w/w)HC in quintuplicate,with two controls of pure soil(with and without plants,respectively)also included.Prior to potting,soil samples were collected from all HC-amended soils and controls and analyzed for soil pH,plant available nutrients(PO4-P and K),and microbial activity using standard laboratory and statistical methods.Immediately after potting,a 6-week seed germination experiment using Chinese cabbage was conducted to determine germination success,followed by a plant growth experiment of equal duration and plant species to determine biomass success.At the end of the study(after a total plant growth period of 12 weeks),each pot was sampled and comparatively analyzed for the same soil properties as at the beginning of the study.Soil pH shifted toward the pH of the HC(6.6)in all soils over the course of the study,but was most expressed in the 20%and 30%application rates,confirming the well-documented liming effect of HC.The addition of HC increased the PO4-P and K contents,particularly with 20%and 30%HC amendments.These results are proposedly due to the large labile C fraction of the HC,which is easily degradable by microorganisms.The rapid decomposition of this C fraction prompted the quick release of the HCs inherently high PO4-P and K content into the soil,and in turn,further stimulated microbial activity,until this fraction was essentially depleted.HC addition did not inhibit seed germination at any rate,presumably due to a lack of phytotoxic compounds in the HC from aging and microbial processes,and furthermore,showed no significant impact(positive or negative)on plant growth in any soil,despite improved soil conditions.In conclusion,although less pronounced,soil improvements were still achievable and maintainable at lower application rates(5%and 10%),whereas higher rates did not ensure greater benefits for plant growth.While the addition of high rates of HC did not detrimentally effect soil quality or plant growth,it could lead to leaching if the nutrient supply exceeds plant requirements and the soil’s nutrient retention capacity.Therefore,this study validates the previous study in the effectiveness of the biogas digestate HC for soil amelioration and suggests that smaller regularly repeated HC applications may be recommendable for soil improvement.展开更多
Hydrochar(HC),produced by hydrothermal carbonization,offers technical advantages over biochar(BC)produced by pyrolysis,and is suitable for soil amelioration,carbon sequestration,and enhanced plant growth.BC grain size...Hydrochar(HC),produced by hydrothermal carbonization,offers technical advantages over biochar(BC)produced by pyrolysis,and is suitable for soil amelioration,carbon sequestration,and enhanced plant growth.BC grain size has been shown to influence nutrient retention,microbial colonization and aggregate formation;however,similar research for HC is lacking.Pot trials were conducted to investigate the influence of HC grain size[coarse(6.3-2 mm),medium(2-0.63 mm)and fine(<0.63 mm)],produced from biogas digestate,for soil improvement in three soils:loamy Chernozem,sandy Podzol,and clayey Gleysol,at a 5%HC application rate(w/w).All soils including two controls(with and without plants)were analysed for water holding capacity(WHC),cation exchange capacity(CEC),wet aggregate stability,pH,plant available nutrients(PO_(4)-P,K and N_(min))and germination and biomass success using standard laboratory and statistical methods.Soil pH showed a compensatory shift toward the HC pH(7.2)in all soils over the course of the study.For example,the pH of the medium grained HC treatment for the Chernozem decreased from 7.9 to 7.2 and increased in the Podzol and Gleysol from 5.9 to 6.1 and 4.9 to 5.5,respectively.The nutrient-rich HC(2034±38.3 mg kg^(−1) PO_(4)-P and 2612.5±268.7 mg kg^(−1) K content)provided only a short-term supply of nutrients,due to the relatively easily mineralized fraction of HC,which allowed for quick nutrient release.The pH and PO_(4)-P effects were most pronounced in the fine grained HC treatments,with a~87%,~308%and~2500%increase in PO_(4)-P content in the Chernozem,Podzol and Gleysol,respectively,compared to the controls at the beginning of the study.The same trend was observed for the K and NH_(4)^(+)content in the fine and medium grained HC treatments in all soils.No seed germination inhibition of Chinese cabbage was observed,with average germina-tion rates>50%in all soils.An effect on NO_(3)^(−)content was indeterminable,while there was little to no effect on biomass production,WHC,CEC and aggregate stability.In conclusion,the application of 5%fine grained HC significantly influenced the nutrient content over a short-term.However,the application rate was insufficient to substantially improve plant growth,nor to sustain a longer-term nutrients supply,regardless of grain size.展开更多
基金supported by grants from the Prairie Oat Grower Association(POGA)Natural Sciences and Engineering Research Council of Canada(NSERC-federal government)Ministry of Agriculture Strategic Research Chair(PY)Program
文摘Background: To our knowledge, there is little study on the interaction between nutrient availability and molecular structure changes induced by different processing methods in dairy cattle. The objective of this study was to investigate the effect of heat processing methods on interaction between nutrient availability and molecular structure in terms of functional groups that are related to protein and starch inherent structure of oat grains with two continued years and three replication of each year.Method: The oat grains were kept as raw(control) or heated in an air-draft oven(dry roasting: DO) at 120 °C for 60 min and under microwave irradiation(MIO) for 6 min. The molecular structure features were revealed by vibrational infrared molecular spectroscopy.Results: The results showed that rumen degradability of dry matter, protein and starch was significantly lower(P <0.05) for MIO compared to control and DO treatments. A higher protein α-helix to β-sheet and a lower amide I to starch area ratio were observed for MIO compared to DO and/or raw treatment. A negative correlation(-0.99, P < 0.01)was observed between α-helix or amide I to starch area ratio and dry matter. A positive correlation(0.99, P < 0.01) was found between protein β-sheet and crude protein.Conclusion: The results reveal that oat grains are more sensitive to microwave irradiation than dry heating in terms of protein and starch molecular profile and nutrient availability in ruminants.
基金the National Key Research and Development Project of China(No.2016YFD0200800)the National Natural Science Foundation of China(No.41571226).
文摘In order to reveal the mechanism of silicon(Si)fertilizer in improving nitrogen(N)and phosphorus(P)nutrient availability in paddy soil,we designed a series of soil culture experiments by combining application of varying Si fertilizer concentrations with fixed N and P fertilizer concentrations.Following the recommendations of fertilizer manufacturers and local farmers,we applied Si in concentrations of 0,5.2,10.4,15.6,and 20.8μg/kg.At each concentration of added Si,the availability of soil N and P nutrients,soil microbial activity,numbers of ammonia-oxidizing bacteria and P-decomposing bacteria which means that the organic P is decomposed into inorganic nutrients which can be absorbed and utilized by plants,and urease and phosphatase activity first increased,and then decreased,as Si was added to the soil.These indicators reached their highest levels with a Si application rate of 15.6μg/kg,showing values respectively 19.78%,105.09%,8.34%,73.12%,130.36%,28.12%,and 20.15%higher than those of the controls.Appropriate Si application(10.4 to 15.6µg/kg)could significantly increase the richness of the soil microbial community involved in cycling of N and P nutrients in the soil.When the Si application rate was 15.6μg/kg,parameters for characterizing microbial abundance such as sequence numbers,operational taxonomic unit(OTU)number,and correlation indices of microbial community richness such as Chao1 index,the adaptive coherence estimator(ACE)index,Shannon index,and Simpson index all reached maximum values,with amounts increased by 14.46%,10.01%,23.80%,30.54%,0.18%,and 2.64%,respectively,compared with the control group.There is also a good correlation between N and P mineralization and addition of Si fertilizer.The correlation coefficients between the ratio of available P/total P(AP/TP)and the number of ammonia-oxidizing bacteria,AP/TP and acid phosphatase activity(AcPA),AP/TP and the Shannon index,the ratio of available N/total amount of N(AN/TN)and the number of ammoniated bacteria,and AN/TN and AcPA were 0.9290,0.9508,0.9202,0.9140,and 0.9366,respectively.In summary,these results revealed that enhancement of soil microbial community structure diversity and soil microbial activity by appropriate application of Si is the key ecological mechanism by which application of Si fertilizer improves N and P nutrient availability.
基金the Scientific Council of the University of Abomey-Calavi,which funded the project untitled“Optimization of Agricultural Production Integrated System without Inputs(OPASISI)”in which this research work has been undertaken.
文摘In spite of the relevance of current studies on the importance of organic fertilizers such as animal manure in improving the health of ecosystems, little is known about the biochemical mechanisms affecting the availability of nutrients released from the organic fertilizer in water. A litter bag study during 6 weeks was carried out in pots containing 25 liters of water with 15 g of pig dejections as organic fertilizers. The experimental design was a completely randomized block design with three replications. The treatments consisted of dejections of pigs nourished with: recommended diet composition T1, partially improved diet with Azolla filiculoides T2, improved diet with Azolla filiculoides T3, improved diet with cereal bran T4. A control treatment without dejection (T0) was considered in the study for comparison purpose. Four pigs per type of diet were considered leading to 16 white landrace pigs of six months age followed for dejection collections. Strong release of nutrients for better yield for agro-fish system was obtained in the manure T1 with ??(10.85 ± 0.00) mg/L;?( 0.011 ± 0.00) mg/L;?(2.13 ± 0.07) mg/L and K+ (10.76 ± 0.57) mg/L;Ca2+ (2.92 ± 0.11) mg/L and Mg2+ (2.53 ± 0.00) mg/L followed by manure T3 and T4 with high N content. The relatively low ratio C/N (14.25) for T1 and (15.84) for T3 induced more nutrients releasing. This study showed an important N loss probably due to microorganism activities which fluctuate nutrient availability. Also significant correlations were noted between the nutrient dynamics in water and physicochemical parameters showing the effect of abiotic factors on organic matter decomposition and mineralization which depend on microbial activities in water and pig manure composition.
基金Supported by Guangxi R&D Project (Gui Ke-AD17195026)Fund of Guangxi Academy of Agricultural Sciences (2019ZX121)。
文摘[Objectives] This study was conducted to explore the differences in soil nutrient contents of cultivated land in different regions of Laos,and to provide a basis for soil nutrient management and scientific fertilization in Laos. [Methods] By collecting 166 samples of the 0-20 cm cultivated soil layer from farmland in the farming areas of Luang Namtha Province in the northern part of Laos and Vientiane Province in the middle of the country,the contents of soil organic matter,total nitrogen,available phosphorus,available potassium,available calcium and available magnesium were analyzed,so as to evaluate the current status of soil nutrient fertility and explore the differences in soil nutrient contents of regional cultivated land. [Results] The soil organic matter was relatively abundant,the total nitrogen and available potassium contents were at the lower-middle level,and the available phosphorus,available calcium and available magnesium were insufficient or extremely insufficient. The soil nutrient contents of cultivated land were different in different regions. [Conclusions] It is suggested that lime or other alkaline fertilizers should be applied on the farmland with acid soil,and nitrogen,phosphorus,and potassium fertilizers should be added at the same time to improve soil nutrient fertility.
基金Supported by Natural Science Foundation of Tibet Autonomous Region(XZ2019ZRG-60).
文摘[Objectives]This study was conducted to investigate the variation characteristics of soil nutrient contents under different land use patterns in the middle and upper reaches of the Niyang River in Tibet.[Methods]With the cultivated land,grass land and forest land in the middle and upper reaches of the Niyang River as the research objects,216 soil samples were collected in layers(0-10,10-20,20-30 cm)by the standard sampling method,and the soil total nitrogen,alkali-hydrolyzable nitrogen,total potassium,available potassium,total phosphorus,available phosphorus and organic matter were determined.[Results]The contents of soil organic matter,total nitrogen and alkali-hydrolyzable nitrogen in the middle and upper reaches of Niyang River in Tibet ranked as forest land>grass land>cultivated land,and there were significant differences between the three(P<0.05).The total potassium contents of grass land and forest land were not much different,and the contents of available potassium exhibited an order of forest land>grass land>cultivated land.The distribution of soil total nutrients and available nutrients under different land use patterns showed a certain degree of surface aggregation.The contents of total nutrients and available nutrients in the soil at the 0-10 cm depth were significantly higher than those at 10-20 and 20-30 cm,and there were significant differences between the three(P<0.05).The average content of alkali-hydrolyzable nitrogen was the largest in forest soil and the smallest in cultivated land under the three land use patterns in the study area.The average content of soil available phosphorus in cultivated land(19.47 mg/kg)was significantly higher than those in grass land(5.73 mg/kg)and forest land(5.19 mg/kg).The above results indicate that long-term vegetation restoration can improve the soil quality of the middle and upper reaches of the Niyang River.[Conclusions]The results of this study research provide basic support for improving the soil effect in the area.
文摘Biochar application is claimed to improve nutrient availability in many problem soils;however, pristine biochars are often reported to produce inconsistent results. Therefore, appropriate biochar modification techniques are required to retain soil nutrients at an optimum level. To increase Nitrogen (N) and Phosphorus (P) availability in coastal saline soil, two slow pyrolyzed biochars viz domestic organic waste (DWB) and farmyard manure (FMB) were modified with MgCl<sub>2</sub>. Ten different treatments comprising the biochars (pristine and modified) with and without the recommended fertilizer were applied (2% w/w) to the soil and incubated for ninety days. The soils were analyzed for pH, EC, available <img src="Edit_0d6ce0cb-4936-4874-a480-35d5b2f585ff.png" alt="" />, <img src="Edit_64cd5bd3-ddeb-4e08-ad2e-48f0710feace.png" alt="" /> and different phosphorus fractions sequentially extracted by NH<sub>4</sub>Cl, NaHCO<sub>3</sub>, NaOH, and HCl. During the incubation period, biochar treatments increased all phosphorus and nitrogen fractions than the control and recommended fertilizer treatment. The application of FMB significantly (<em>p</em> < 0.05) increased NH<sub>4</sub>Cl, NaHCO<sub>3</sub>, and NaOH extractable P fractions from DWB, while HCl soluble fraction was enhanced (<em>p</em> > 0.05) by DWB. The increased Al and/or Fe bound phosphate after 60 days of incubation had significant correlations to decreasing soil pH and NaHCO<sub>3</sub>-P, indicating reduced availability with time. Further Mg modification slightly increased P availability only after 60 days of incubation. The modification also improved both nitrogen fractions but significantly (<em>p</em> < 0.05) increased the NO<sub>3</sub>-N content which could be the result of electrostatic attraction between Mg<sup>2</sup>+ and <img src="Edit_c55861ac-dd25-4c26-9ecc-2e134a948b8e.png" alt="" /> ions. Overall, Mg-modified biochar may retain both phosphates and nitrates in soil. However, the magnitude of retention will vary depending on biochar type, nutrient species, and aging in soil.
文摘Inoculation of alfalfa seedlings with root growth promoting microorganisms under semi-arid climate condition may improve biomass production and nutritive value.The current study aimed to investigate the effect of inoculation of alfalfa seedlings with Piriformospora indica(Pi) and co-inoculating Pi with Glomus intraradices(Gi+Pi) or Sinorhizobium meliloti(Sm+Pi) on hay yield,chemical composition,molecular structures by Fourier transformed infrared(FTIR) spectroscopy,in situ ruminal degradability and in vitro gas production.Seedlings were grown in experimental pots in a greenhouse until first cut and then transferred outside and cut a further 4 times.Biomass yield was similar across the treatments.Acid detergent fiber(ADF) concentration was higher in Pi than in control hay,and ADF decreased further with co-inoculation(P < 0.05).The ether extract(EE) concentration was lower for Pi and Gi+Pi compared with control hay,and control,Pi and Gi+Pi hays had lower EE concentration compared with Sm+Pi(P < 0.05).The FTIR spectroscopic vibration peak height ratio related to proteins(amide1+amide 2): total carbohydrate ratio was lower for the inoculation treatments compared with control hay(P < 0.05).In situ ruminal degradability of dry matter and organic matter were higher for hay of inoculated and co-inoculated seedlings than for control hay(P < 0.05).In conclusion,hay of alfalfa seedlings inoculated and co-inoculated with root growth promoting microorganisms had improved nutritional value compared with hay from non-treated alfalfa seedlings,and co-inoculation was the most effective,however,changes were relatively minor.
文摘Forest fires are key ecosystem modifiers affecting the biological,chemical,and physical attributes of forest soils.The extent of soil disturbance by fire is largely dependent on fire intensity,duration and recurrence,fuel load,and soil characteristics.The impact on soil properties is intricate,yielding different results based on these factors.This paper reviews research investigating the effects of wildfire and prescribed fire on the biological and physico-chemical attributes of forest soils and provides a summary of current knowledge associated with the benefits and disadvantages of such fires.Low-intensity fires with ash deposition on soil surfaces cause changes in soil chemistry,including increase in available nutrients and pH.High intensity fires are noted for the complete combustion of organic matter and result in severe negative impacts on forest soils.High intensity fires result in nutrient volatilization,the break down in soil aggregate stability,an increase soil bulk density,an increase in the hydrophobicity of soil particles leading to decreased water infiltration with increased erosion and destroy soil biota.High soil heating(> 120℃) from high-intensity forest fires is detrimental to the soil ecosystem,especially its physical and biological properties.In this regard,the use of prescribed burning as a management tool to reduce the fuel load is highly recommended due to its low intensity and limited soil heating.Furthermore,the use of prescribed fires to manage fuel loads is critically needed in the light of current global warming as it will help prevent increased wildfire incidences.This review provides information on the impact of forest fires on soil properties,a key feature in the maintenance of healthy ecosystems.In addition,the review should prompt comprehensive soil and forest management regimes to limit soil disturbance and restore fire-disturbed soil ecosystems.
基金National Basic Research Program of China(973 Program)(2012CB416906)State Key Laboratory of Forest and Soil Ecology(LFSE2013-11).
文摘Aims Conversion of secondary forests to pure larch plantations is a common management practice driven by the increasing demand for timber production in Northeast China,resulting in a reduction in soil nutrient availability after a certain number of years following conversion.Nutrient resorption prior to leaf senescence was related to soil fertility,an important nutrient conservation strategy for plants,being especially significant in nutrient-poor habitats.However,the seasonal dynamics of leaf nutrients and nutrient resorption in response to secondary forest conversion to larch plantations is not well understood.Methods A comparative experiment between larch plantations(Larix spp.)and adjacent secondary forests(dominant tree species including Quercus mongolica,Acer mono,Juglans mandshurica and Fraxinus rhynchophylla)was conducted.We examined the variations in leaf nutrient(macronutrients:N,P,K,Ca and Mg;micronutrients:Cu and Zn)concentrations of these tree species during the growing season from May to October in 2013.Nutrient resorption efficiency and proficiency were compared between Larix spp.and the broadleaved species in the secondary forests.Important Findings Results show that the seasonal variation of nutrient concentrations in leaves generally exhibited two trends,one was a downward trend for N,P,K,Cu and Zn,and another was an upward trend for Ca and Mg.The variations in foliar nutrient concentrations were mainly controlled by the developmental stage of leaves rather than by tree species.Resorption of the observed seven elements varied among the five tree species during leaf senescence.Nutrient resorption efficiency varied 6–75%of N,P,K,Mg,Cu and Zn,while Ca was not retranslocated in the senescing leaves of all species,and Mg was not retranslocated in Larix spp.Generally,Larix spp.tended to be more efficient and proficient(higher than 6–30%and 2–271%of nutrient resorption efficiency and resorption proficiency,respectively)in resorbing nutrients than the broadleaved species in the secondary forests,indicating that larch plantations had higher leaf nutrient resorption and thus nutrient use efficiency.Compared with Larix spp.,more nutrients would remain in the leaf litter of the secondary forests,indicating an advantage of secondary forests in sustaining soil fertility.In contrast,the larch plantation would reuse internal nutrients rather than lose nutrients with litter fall and thus produce a positive feedback to soil nutrient availability.In summary,our results suggest that conversion from secondary forests to pure larch plantations would alter nutrient cycling through a plantmediated pathway.
文摘Biochars,when applied to contaminated solutions or soils,may sequester potentially toxic elements while releasing neces-sary plant nutrients.This purpose of this study focused on quantifying both phenomenon following wheat straw(Triticum aestivum L.)biochar application(0,5,and 15%by wt)to a Cd containing solution and a Cd-contaminated paddy soil using 240-day laboratory batch experiments.Following both experiments,solid phases were analyzed for elemental associations using a combination of wet chemical sequential extractions and synchrotron-based X-ray absorption spectroscopy(XAS).When wheat straw biochar was applied at 15%to Cd containing solutions,Cd and Zn concentrations decreased to below detection in some instances,Ca and Mg concentrations increased by up to 290%,and solution pH increased as compared to the 5%biochar application rate.Similar responses were observed when biochar was added to the Cd-contaminated paddy soil,suggesting that this particular biochar has the ability to sequester potentially toxic elements while releasing necessary plant nutrients to the soil solution.When significant,positive correlations existed between nutrient release over time,while negative correlations were present between biochar application rate,potentially toxic element sorption and pH.The latter suggests that potentially toxic elements were sorbed by a combination of organic functional groups or mineral precipitation based on whether pH was above or below~7.In support of this contention,the wet chemical sequential extraction procedure in conjunction with previously observed Cd or current Zn XAS showed that biochar application promoted the formation of layered double hydroxides,sorption to(oxy)hydroxides,and organically bound to biochar as Zn species.As a multi-functional material,biochar appears to play an important role in sequestering Cd while releasing essential plant nutrients.These findings suggest that biochar may be a‘win-win’for improving environmental quality in potentially toxic element contaminated agroecosystems.
基金supported by Spanish Government grants PID2020-112738GB-I00,PID2019-110521GB-I00,and TED2021-132627B-I00Fundacion Ramon Areces grant CIVP20A6621,and Catalan Government grant SGR2017-1005.
文摘Foliar nutrient resorption(NuR)plays a key role in ecosystem functioning and plant nutrient economy.Most of this recycling occurs during the senescence of leaves and is actively addressed by cells.Here,we discuss the importance of cell biochemistry,physiology,and subcellular anatomy to condition the outcome of NuR at the cellular level and to explain the existence of limits to NuR.Nutrients are transferred from the leaf in simple metabolites that can be loaded into the phloem.Proteolysis is the main mechanism for mobilization of N,whereas P mobilization requires the involvement of different catabolic pathways,making the dynamics of P in leaves more variable than those of N before,during,and after foliar senescence.The biochemistry and fate of organelles during senescence impose constraints that limit NuR.The efficiency of NuR decreases,especially in evergreen species,as soil fertility increases,which is attributed to the relative costs of nutrient acquisition from soil decreasing with increasing soil nutrient availability,while the energetic costs of NuR from senescing leaves remain constant.NuR is genetically determined,with substantial interspecific variability,and is environmentally regulated in space and time,with nutrient availability being a key driver of intraspecific variability in NuR.
基金supported by MOST(2015CB910401 to Q.-Y.L)the Natural Science Foundation of China(81790253,81790250,and 81430057 to Q.-Y.L,81772946 and 81502379 to Y.-P.W.)+1 种基金the Innovation Program of Shanghai Municipal Education Commission(N173606 to Q.-Y.L.)the“Chenguang Program”of the Shanghai Education Development Foundation(14CG15 to Y.-P.W).
文摘Dysregulation of metabolism allows tumor cells to generate needed building blocks as well as to modulate epigenetic marks to support cancer initiation and progression.Cancer-induced metabolic changes alter the epigenetic landscape,especially modifications on histones and DNA,thereby promoting malignant transformation,adaptation to inadequate nutrition,and metastasis.Recent advances in cancer metabolism shed light on how aberrations in metabolites and metabolic enzymes modify epigenetic programs.The metabolism-induced recoding of epigenetics in cancer depends strongly on nutrient availability for tumor cells.In this review,we focus on metabolic remodeling of epigenetics in cancer and examine potential mechanisms by which cancer cells integrate nutritional inputs into epigenetic modification.
基金This work was financially supported by the National Natural Science Foundation of China(32101330,42141006 and 31988102)the China Postdoctoral Science Foundation(2021M690217).
文摘Microbial carbon use efficiency(CUE)is an important factor driving soil carbon(C)dynamics.However,microbial CUE could positively,negatively,or neutrally respond to increased temperature,which limits our prediction of soil C storage under future climate warming.Experimental warming affects plant production and microbial communities,which thus can have a significant impact on biogeochemical cycles of terrestrial ecosystems.Here,we reviewed the present research status of methods measuring microbial CUE and the response of microbial CUE to the changes of biotic and abiotic factors induced by warming.Overall,current measurement methods mainly include metabolic flux analysis,calorespirometry,stoichiometric model,13C and 18O labeling.Differences in added substrate types can lead to an overestimation or underestimation on microbial CUE,particularly when using the 13C labeling method.In addition,changes in the dominant microbial community under warming may also affect CUE.However,there is still uncertainty in CUE characteristics of different microorganisms.Microbial CUE is generally decreased under warming conditions as microbes are subjected to water stress or soil labile organic matter is much more depleted compared to ambient conditions.In contrast,considering that warming increases soil nutrient availability,warming may enhance microbial CUE by alleviating nutrient limitations for microbes.In conclusion,the response of microbial CUE to warming is more complex than expected.The microbial growth and physiological adaptation to environmental stress under warming is one of the main reasons for the inconsistence in microbial CUE response.Finally,we propose five aspects where further research could improve the understanding of microbial CUE in a warmer world,including using new technologies,establishing multi-factor interactive experiments,building a network of experimental research platform for warming,and strengthening studies on response of CUE to warming at different soil depths and on different temporal scales.
基金financially supported by the Agricultural Linkages Programme (ALP) of Pakistan Agricultural Research Council (PARC) (ALP/PARC) (No.CS-268) on Microbial Biotechnology for Sustainable Production of LegumesProf.Dr.Zahir A.Zahir, Soil Microbiology & Biochemistry Laboratory, Institute of Soil and Environmental Sciences, University of Agriculture Faisalabad, Pakistan, for providing financial and logistic support to carry out the present investigation
文摘Legume plants are an essential component of sustainable farming systems.Phosphorus(P) deficiency is a significant constraint for legume production, especially in nutrient-poor soils of arid and semi-arid regions.In the present study, we conducted a pot experiment to evaluate the effects of a phosphorus-mobilizing plant-growth promoting rhizobacterial strain Bacillus cereus GS6, either alone or combined with phosphate-enriched compost(PEC) on the symbiotic(nodulation-N_2 fixation) performance of soybean(Glycine max(L.) Merr.) on an Aridisol.The PEC was produced by composting food waste with addition of single super phosphate.The bacterial strain B.cereus GS6 showed considerable potential for P solubilization and mobilization by releasing carboxylates in insoluble P(rock phosphate)-enriched medium.Inoculation of B.cereus GS6 in combination with PEC application significantly improved nodulation and nodule N_2 fixation efficiency.Compared to the control(without B.cereus GS6 and PEC), the combined application of B.cereus GS6 with PEC resulted in significantly higher accumulation of nitrogen(N), P, and potassium(K) in grain, shoot, and nodule.The N:P and P:K ratios in nodules were significantly altered by the application of PEC and B.cereus GS6, which reflected the important roles of P and K in symbiotic performance of soybean.The combined application of PEC and B.cereus GS6 also significantly increased the soil dehydrogenase and phosphomonoesterase activities, as well as the soil available N, P, and K contents.Significant positive relationships were found between soil organic carbon(C) content, dehydrogenase and phosphomonoesterase activities, and available N, P, and K contents.This study suggests that inoculation of P-mobilizing rhizobacteria, such as B.cereus GS6, in combination with PEC application might enhance legume productivity by improving nodulation and nodule N_2 fixation efficiency.
基金National Natural Science Foundation of China(51179041)Major Science and Technology Program for Water Pollution Control and Treatment(2012ZX07201003)+3 种基金Natural Science Foundation of Hei Longjiang Province,China(E201206)State Key Lab of Urban Water Resource and Environment(Harbin Institute of Technology)(2014TS05)ARC Centre of Excellence in Plant Energy Biology(CE140100008 to O.K.A.)ARC Linkage grant(LP0990330 to O.K.A.).
文摘Aims Changes in the phenotype of crops(phenotypic plasticity)are known to play an important role in determining responses to nutrient availability,with the direction and magnitude of plasticity of individual traits being crucial for grain yields.Our study analysed the direction,magnitude and hierarchy of plastic responses of yieldrelated traits(i.e.biomass allocation and yield components)of rice(Oryza sativa L.)to nutrient availability.We estimated the effect of inoculation with arbuscular mycorrhizal fungi(AMF)on these characteristics of phenotypic plasticity.Methods A field experiment was carried out in northeast China,providing rice with six NPK fertilizer levels with or without inoculation with Glomus mosseae.At maturity,we quantified biomass allocation traits(shoot:root ratio and panicle:shoot ratio)and yield component traits(panicle number per hill,spikelet number per panicle,percentage of filled spikelets and seed weight).We also assessed the direction of change in each trait and the magnitude of trait plasticity.Important Findings In non-inoculated plants,we found that biomass allocation and seed-number traits(i.e.panicle number per hill,spikelet number per panicle and percentage of filled spikelets)responded to fertilization in the same direction,increasing with rising fertilization.Panicle formation was the most plastic trait,while seed mass was the least plastic trait.AMF inoculation nullified the relationship between most biomass allocation and seed-number traits(except for that between panicle:shoot ratio and the percentage of filled spikelets)but increased the magnitude of plasticity in biomass allocation traits without altering the hierarchy of traits’plasticity.These results underscore the importance of plasticity of yield-related traits per se,and the impact of AMF on plasticity,for maintaining rice yields under low fertilization regimes.
基金This study was conducted under the auspices of the‘BIOCAS,circular BIOmass CAScade to 100%’project,which is funded by the European Union Interreg North Sea Region Project 38-2-4-17The funders played no role in the design of the study,the collection and analyses of data or the preparation of the manuscript.
文摘The hydrothermal carbonization(HTC)of biogas digestate alters the raw materials inherent characteristics to produce a carbon(C)-rich hydrochar(HC),with an improved suitability for soil amelioration.Numerous studies report conflicting impacts of various HC application rates on soil properties and plant growth.In this study,the influence of HC application rate on soil improvement and plant growth aspects was investigated in three diverse soils(Chernozem,Podzol,and Gleysol).Pot trials were conducted in which all soils were amended with 5,10,20 and 30%(w/w)HC in quintuplicate,with two controls of pure soil(with and without plants,respectively)also included.Prior to potting,soil samples were collected from all HC-amended soils and controls and analyzed for soil pH,plant available nutrients(PO4-P and K),and microbial activity using standard laboratory and statistical methods.Immediately after potting,a 6-week seed germination experiment using Chinese cabbage was conducted to determine germination success,followed by a plant growth experiment of equal duration and plant species to determine biomass success.At the end of the study(after a total plant growth period of 12 weeks),each pot was sampled and comparatively analyzed for the same soil properties as at the beginning of the study.Soil pH shifted toward the pH of the HC(6.6)in all soils over the course of the study,but was most expressed in the 20%and 30%application rates,confirming the well-documented liming effect of HC.The addition of HC increased the PO4-P and K contents,particularly with 20%and 30%HC amendments.These results are proposedly due to the large labile C fraction of the HC,which is easily degradable by microorganisms.The rapid decomposition of this C fraction prompted the quick release of the HCs inherently high PO4-P and K content into the soil,and in turn,further stimulated microbial activity,until this fraction was essentially depleted.HC addition did not inhibit seed germination at any rate,presumably due to a lack of phytotoxic compounds in the HC from aging and microbial processes,and furthermore,showed no significant impact(positive or negative)on plant growth in any soil,despite improved soil conditions.In conclusion,although less pronounced,soil improvements were still achievable and maintainable at lower application rates(5%and 10%),whereas higher rates did not ensure greater benefits for plant growth.While the addition of high rates of HC did not detrimentally effect soil quality or plant growth,it could lead to leaching if the nutrient supply exceeds plant requirements and the soil’s nutrient retention capacity.Therefore,this study validates the previous study in the effectiveness of the biogas digestate HC for soil amelioration and suggests that smaller regularly repeated HC applications may be recommendable for soil improvement.
基金Open Access funding provided by Projekt DEAL.This study was conducted under the auspices of the Circular BIOmass CAScade to 100%(BIOCAS)project,which is funded by the European Union Interreg North Sea Region Project 38-2-4-17.
文摘Hydrochar(HC),produced by hydrothermal carbonization,offers technical advantages over biochar(BC)produced by pyrolysis,and is suitable for soil amelioration,carbon sequestration,and enhanced plant growth.BC grain size has been shown to influence nutrient retention,microbial colonization and aggregate formation;however,similar research for HC is lacking.Pot trials were conducted to investigate the influence of HC grain size[coarse(6.3-2 mm),medium(2-0.63 mm)and fine(<0.63 mm)],produced from biogas digestate,for soil improvement in three soils:loamy Chernozem,sandy Podzol,and clayey Gleysol,at a 5%HC application rate(w/w).All soils including two controls(with and without plants)were analysed for water holding capacity(WHC),cation exchange capacity(CEC),wet aggregate stability,pH,plant available nutrients(PO_(4)-P,K and N_(min))and germination and biomass success using standard laboratory and statistical methods.Soil pH showed a compensatory shift toward the HC pH(7.2)in all soils over the course of the study.For example,the pH of the medium grained HC treatment for the Chernozem decreased from 7.9 to 7.2 and increased in the Podzol and Gleysol from 5.9 to 6.1 and 4.9 to 5.5,respectively.The nutrient-rich HC(2034±38.3 mg kg^(−1) PO_(4)-P and 2612.5±268.7 mg kg^(−1) K content)provided only a short-term supply of nutrients,due to the relatively easily mineralized fraction of HC,which allowed for quick nutrient release.The pH and PO_(4)-P effects were most pronounced in the fine grained HC treatments,with a~87%,~308%and~2500%increase in PO_(4)-P content in the Chernozem,Podzol and Gleysol,respectively,compared to the controls at the beginning of the study.The same trend was observed for the K and NH_(4)^(+)content in the fine and medium grained HC treatments in all soils.No seed germination inhibition of Chinese cabbage was observed,with average germina-tion rates>50%in all soils.An effect on NO_(3)^(−)content was indeterminable,while there was little to no effect on biomass production,WHC,CEC and aggregate stability.In conclusion,the application of 5%fine grained HC significantly influenced the nutrient content over a short-term.However,the application rate was insufficient to substantially improve plant growth,nor to sustain a longer-term nutrients supply,regardless of grain size.
