Background Cotton is a strategically important fibre crop for global textile industry.It profoundly impacts several countries’industrial and agricultural sectors.Sustainable cotton production is continuously threaten...Background Cotton is a strategically important fibre crop for global textile industry.It profoundly impacts several countries’industrial and agricultural sectors.Sustainable cotton production is continuously threatened by the unpre-dictable changes in climate,specifically high temperatures.Breeding heat-tolerant,high-yielding cotton cultivars with wide adaptability to be grown in the regions with rising temperatures is one of the primary objectives of modern cotton breeding programmes.Therefore,the main objective of the current study is to figure out the effective breed-ing approach to imparting heat tolerance as well as the judicious utilization of commercially significant and stress-tolerant attributes in cotton breeding.Initially,the two most notable heat-susceptible(FH-115 and NIAB Kiran)and tolerant(IUB-13 and GH-Mubarak)cotton cultivars were spotted to develop filial and backcross populations to accom-plish the preceding study objectives.The heat tolerant cultivars were screened on the basis of various morphological(seed cotton yield per plant,ginning turnout percentage),physiological(pollen viability,cell membrane thermostabil-ity)and biochemical(peroxidase activity,proline content,hydrogen peroxide content)parameters.Results The results clearly exhibited that heat stress consequently had a detrimental impact on every studied plant trait,as revealed by the ability of crossing and their backcross populations to tolerate high temperatures.However,when considering overall yield,biochemical,and physiological traits,the IUB-13×FH-115 cross went over particularly well at both normal and high temperature conditions.Moreover,overall seed cotton yield per plant exhibited a posi-tive correlation with both pollen viability and antioxidant levels(POD activity and proline content).Conclusions Selection from segregation population and criteria involving pollen viability and antioxidant levels concluded to be an effective strategy for the screening of heat-tolerant cotton germplasms.Therefore,understanding acquired from this study can assist breeders identifying traits that should be prioritized in order to develop climate resilient cotton cultivars.展开更多
The application of Si or K has proven to be beneficial for the growth of plants under saline-alkali stress. However, the synergistic effect of Si and K in improving the growth, ion distribution, and partitioning in Lo...The application of Si or K has proven to be beneficial for the growth of plants under saline-alkali stress. However, the synergistic effect of Si and K in improving the growth, ion distribution, and partitioning in Lolium perenne L. under saline-alkali stress remains unclear. In this study, the growth characteristics and ion-selective absorption of ryegrass(Lolium perenne L.) exposed to different levels of saline-alkali stress were evaluated. The growth parameters of ryegrass were significantly improved when Si was applied by itself or coupled with K under low saline-alkali stress. Under a high saline-alkali level, only simultaneous application of Si and K could significantly improve the growth of ryegrass. When Si and K were applied together, the K^(+)/Na^(+) and Ca^(2+)/Na^(+) ratios in root, stem, and leaf of ryegrass were maximally improved as compared to the individual treatments and control. The K^(+) and Ca^(2+) concentrations in the vacuole, cell wall, and organelle of leaf were increased dramatically. This improvement was due to the ability of applied ions to compete with Na^(+), allowing the plant to maintain osmotic potential and leaf water content. The concentration of Na^(+) was significantly reduced when Si and K were applied and mainly concentrated in the soluble fraction and cell wall. The Si concentration in ryegrass increased markedly by the combined application of Si and K, and most of it was accumulated in the cell wall and soluble fraction, which could help in chlorophyll synthesis, reduce membrane injury, and increase water absorption under saline-alkali stress. This study emphasized the advantage of Si and/or K on the growth of plants under different saline-alkaline levels and provided a guide for the production of Si-K fertilizer and its application in saline-alkali soil.展开更多
Global demand for vegetable oil is anticipated to double by 2030. The current vegetable oil production platforms, including oil palm and temperate oilseeds, are unlikely to produce such an expansion. Therefore, the ex...Global demand for vegetable oil is anticipated to double by 2030. The current vegetable oil production platforms, including oil palm and temperate oilseeds, are unlikely to produce such an expansion. Therefore, the exploration of novel vegetable oil sources has become increasingly important in order to make up this future vegetable oil shortfall. Triacylglycerol （TAG）, as the dominant form of vegetable oil, has recently attracted immense interest in terms of being produced in plant vegetative tissues via genetic engineering technologies. Multidiscipline-based ＂-omics＂ studies are increasingly enhancing our understanding of plant lipid biochemistry and metabolism. As a result, the identification of biochemical pathways and the annotation of key genes contributing to fatty acid biosynthesis and to lipid assembly and turnover have been effectively updated. In recent years, there has been a rapid development in the genetic enhancement of TAG accumulation in high-biomass plant vegetative tissues and oilseeds through the genetic manipulation of the key genes and regulators involved in TAG biosynthesis. In this review, current genetic engineering strategies ranging from single-gene manipulation to multigene stacking aimed at increasing plant biomass TAG accumulation are summarized. New directions and suggestions for plant oil production that may help to further alleviate the potential shortage of edible oil and biodiesel are discussed.展开更多
Background:Plants respond to changes in vapour pressure deficit(VPD)between the leaf and the atmosphere through changes in stomatal response,which can consequently affect transpiration,photosynthesis,and leaf-level wa...Background:Plants respond to changes in vapour pressure deficit(VPD)between the leaf and the atmosphere through changes in stomatal response,which can consequently affect transpiration,photosynthesis,and leaf-level water use efficiencies.With projected warmer air temperatures,changes in rainfall distribution and altered VPD in future climates,it is important to understand the potential effect of VPD on leaf-level physiology of field-grown crops.The aim of this study was to assess the impact of altered VPD on leaf-level physiology of field-grown cotton to improve the current understanding of the plant-by-environment interaction,thereby contributing to validation and improvement of physiological and yield response models.Different VPD environments in the field were generated by planting cotton on three dates within the sowing window(early-season(S1)=5th October 2011;mid-season(S2)=9th November 2011;and late-season(S3)=30th November 2011).VPD was also modified by altering crop irrigations.Results:VPDL accounted for the largest proportion of the explained variation in both stomatal conductance(32%∼39%)and photosynthetic(16%∼29%)responses of cotton.Generally,smaller percentages of variation were attributed to other main factors such as the individual plant(Plant),and accumulated temperature stress hours(ASH;a measure of plant water status over time)and interactive factors,including leaf vapour pressure deficit(VPDL)×Plant and Plant×ASH;however,a proportion of variation was unexplained.In addition,the Asat/E(instantaneous transpiration efficiency,ITE)model developed based on cotton grown in the glasshouse was applied to cotton grown in the field.We found that the modelled Asat/E and field-measured Asat/E were very similar,suggesting that the mechanistic basis for ITE was similar in both environments.Conclusions:This study highlights the importance of accounting for VPD in climate change research,given that stomata are highly responsive to changes in VPD.This experiment provides a basis for physiology and production models,particularly in terms of cotton response to projected climatic environments.展开更多
Digital maps of soil properties are now widely available.End-users now can access several digital soil mapping(DSM)products of soil properties,produced using different models,calibration/training data,and covariates a...Digital maps of soil properties are now widely available.End-users now can access several digital soil mapping(DSM)products of soil properties,produced using different models,calibration/training data,and covariates at various spatial scales from global to local.Therefore,there is an urgent need to provide easy-to-understand tools to communicate map uncertainty and help end-users assess the reliability of DSM products for use at local scales.In this study,we used a large amount of hand-feel soil texture(HFST)data to assess the performance of various published DSM products on the prediction of soil particle size distribution in Central France.We tested four DSM products for soil texture prediction developed at various scales(global,continental,national,and regional)by comparing their predictions with approximately 3200 HFST observations realized on a 1:50000 soil survey conducted after release of these DSM products.We used both visual comparisons and quantitative indicators to match the DSM predictions and HFST observations.The comparison between the low-cost HFST observations and DSM predictions clearly showed the applicability of various DSM products,with the prediction accuracy increasing from global to regional predictions.This simple evaluation can determine which products can be used at the local scale and if more accurate DSM products are required.展开更多
Aims Crop nitrogen(N)and phosphorus(P)stoichiometry can influence food nutritive quality and many ecosystem processes.However,how and why N and P stoichiometry respond to long-term agricul-tural management practices(e...Aims Crop nitrogen(N)and phosphorus(P)stoichiometry can influence food nutritive quality and many ecosystem processes.However,how and why N and P stoichiometry respond to long-term agricul-tural management practices(e.g.N fertilization and film mulching)are not clearly understood.Methods We collected maize tissues(leaf,stem,root and seed)and soil sam-ples from a temperate cropland under 30-year continuous N fer-tilization and plastic film mulching treatments,measured their C,N and P concentrations(the proportion(%)relative to the sample mass),and used structural equation models to uncover the re-sponding mechanisms for crop N and P contents(the total amount(g/m2)in crop biomass).Important Findings Long-term N fertilization increased N concentrations in all crop tissues but sharply decreased P concentrations in vegetative tis-sues(leaf,stem and root),thereby reducing their C/N ratio and increasing C/P and N/P ratios.The drop in P concentration in vegetative tissues was due to the dilution effect by biomass in-crement and the priority of P supply for seed production.In con-trast,film mulching decreased N concentration but increased P concentrations in most crop tissues,thereby increasing C/N ratio and reducing C/P and N/P ratios.Film mulching increased crop P content by increasing soil temperature and moisture;whereas,mulching showed little effect on crop N content,because a posi-tive effects of soil temperature may have canceled out a negative effect by soil moisture.This indicated a decoupling of P and N uptake by crops under film mulching.In conclusion,N fertiliza-tion and plastic film mulching showed opposite effects of on crop N and P stoichiometry.展开更多
In this study the starch digestion rates in broiler chickens from 18 samples of 5 commonly used feed grains(sorghum,wheat,maize,barley,triticale)were determined.The methodology to determine starch digestion rates in p...In this study the starch digestion rates in broiler chickens from 18 samples of 5 commonly used feed grains(sorghum,wheat,maize,barley,triticale)were determined.The methodology to determine starch digestion rates in poultry is detailed herein.Starch digestion rates were not significantly different(P-0.128)across the 18 feed grains,which reflects the wide variations that were observed within a given feedstuff.Nevertheless,starch digestion rates in broiler chickens offered wheat-based diets were significantly more rapid by 56.0%(0.117 versus 0.075 min-1;p=0.012)than their sorghum-based counterparts on the basis of a pair-wise comparison.In descending order,the following starch diges-tion rates were observed:wheat(0.117 min-1),barley(0.104 min-1),triticale(0.093 min-1),maize(0.086 min-1),sorghum(0.075 min-1).The implications of these findings are discussed as they almost certainly have implications for poultry nutrition and the development of reduced crude protein diets for broiler chickens.展开更多
Soil organic carbon(SOC)is the largest terrestrial carbon(C)stock,and the capacity of soils to preserve organic C(OC)varies with many factors,including land use,soil type,and soil depth.We investigated the effect of l...Soil organic carbon(SOC)is the largest terrestrial carbon(C)stock,and the capacity of soils to preserve organic C(OC)varies with many factors,including land use,soil type,and soil depth.We investigated the effect of land use change on soil particulate organic matter(POM)and mineral-associated organic matter(MOM).Surface(0–10 cm)and subsurface(60–70 cm)samples were collected from paired sites(native and cropped)of four contrasting soils.Bulk soils were separated into POM and MOM fractions,which were analyzed for mineralogy,OC,nitrogen,isotopic signatures,and14C.The POM fractions of surface soils were relatively unaffected by land use change,possibly because of the continuous input of crop residues,whereas the POM fractions in corresponding subsurface soils lost more OC.In surface soils,MOM fractions dominated by the oxides of iron and aluminum(oxide-OM)lost more OC than those dominated by phyllosilicates and quartz,which was attributed to diverse organic matter(OM)input and the extent of OC saturation limit of soils.In contrast,oxide-OM fractions were less affected than the other two MOM fractions in the subsurface soils,possibly due to OC protection via organo-mineral associations.The deviations in isotopic signature(linked with vegetation)across the fractions suggested that fresh crop residues constituted the bulk of OM in surface soils(supported by greater14C).Increased isotopic signatures and lower14C in subsurface MOM fractions suggested the association of more microbially processed,aged OC with oxide-OM fractions than with the other MOM fractions.The results reveal that the quantity and quality of OC after land use change is influenced by the nature of C input in surface soils and by mineral-organic association in subsurface soils.展开更多
This review is an outlook for sorghum as a feed grain for broiler chickens based on a survey of relevant stake-holders and recent research outcomes.Australian grain sorghum production will probably continue to generat...This review is an outlook for sorghum as a feed grain for broiler chickens based on a survey of relevant stake-holders and recent research outcomes.Australian grain sorghum production will probably continue to generate a harvest in the order of 2.5×10~6t of which some 7.9×10~5t will be used as a feed grain for poultry and pigs.Feed grains are included primarily to provide energy from starch,but energy utilisation by broiler chickens offered sorghum-based diets is relatively inferior,because of incomplete starch digestion.Kafirin,the dominant protein fraction,‘non-tannin’phenolic compounds and phytate are 3‘starch extrinsic’factors in sorghum that compromise starch digestibility and energy utilisation in broiler chickens offered sorghum-based diets.Kafirin concentrations in 6 sorghum varieties were negatively correlated with metabolizable energy to gross energy(ME:GE)ratios(r=0.891;P<0.02)or the efficiency of energy utilisation in broiler chickens.Importantly,kafirin proportions of sorghum protein may be increasing with time in Australia.If so,this represents a fundamental challenge to sorghum breeders which presumably could be met by the development of sorghum varieties with different characteristics,especially in relation to the g-and b-kafirin fractions.White sorghum varieties contain lower polyphenol concentrations which should be advantageous as concentrations of total phenolic compounds were negatively correlated to ME:GE ratios(r=0.838;P<0.04)in 6 sorghum varieties.It would be desirable if more white varieties were to become available.It is suggested that responses to exogenous phytase in birds offered sorghum-based diets would be more robust if sorghum were to contain lower concentrations of kafirin and phenolic compounds.Paradoxically,while better sorghum varieties almost certainly could be developed,it may not necessarily follow that they will command a price premium from poultry and pig producers.展开更多
Soil is the foundation for sustainable foodproduction and environmental protection. Created byunsustainable land management practices and a range ofsocial, economic and environmental drivers, soil degrada-tion and pol...Soil is the foundation for sustainable foodproduction and environmental protection. Created byunsustainable land management practices and a range ofsocial, economic and environmental drivers, soil degrada-tion and pollution have been an ongoing threat tointernational food security and environmental quality.Soil degradation and pollution assessments are, however,often focused on the soil itself with little scope to devisenew soil management approaches that match foodproduction systems and/or environmentalprotection.This study draws lessons from an Australia-China JointResearch Center Program, Healthy Soils for SustainableFood Production and Environmental Quality: a researchplatform that has brought together multi-disciplinaryapproaches fromworld-renowned universitiesandresearch organizations in Australia and China. To thisend, a framework is presented for future soil managementin a new way that combines excellence in research,industry and policymakers in a partnership that will ensurenot only the right focus of the research but also that high-quality outputs will be transferable to industry and end-users.展开更多
Human disturbances to soils can lead to dramatic changes in soil physical,chemical,and biological properties.The influence of agricultural activities on the bacterial community over different orders of soil and at dep...Human disturbances to soils can lead to dramatic changes in soil physical,chemical,and biological properties.The influence of agricultural activities on the bacterial community over different orders of soil and at depth is still not well understood.We used the concept of genoform and phenoform to investigate the vertical(down to 1 m depth)soil bacterial community structure in paired genosoils(undisturbed forests)and phenosoils(cultivated vineyards)in different soil orders.The study was conducted in the Hunter Valley area,New South Wales,Australia,where samples were collected from 3 different soil orders(Calcarosol,Chromosol,and Kurosol),and each soil order consists of a pair of genosoil and phenosoil.The bacterial community structure was analyzed using highthroughput sequencing of 16S rRNA.Results showed that bacterial-diversity decreased with depth in phenosoils,however,the trend is less obvious in genoform profiles.Topsoil diversity was greater in phenosoils than genosoils,but the trend was reversed in subsoils.Thus,cropping not only affected topsoil bacteria community but also decreased its diversity in the subsoil.Bacterial community in topsoils was influenced by both soil orders and soil forms,however,in subsoils it was more impacted by soil orders.Constrained Analysis of Principal Coordinates revealed that cropping increased the similarity of bacterial structures of different soil orders.This study highlighted the strong influence of agricultural activities on soil microbial distribution with depth,which is controlled by soil order.展开更多
基金Centre for Advance Studies in Agricultural Food Security and Punjab Agricultural Research Board for providing funds under CAS-PARB project(No.964).
文摘Background Cotton is a strategically important fibre crop for global textile industry.It profoundly impacts several countries’industrial and agricultural sectors.Sustainable cotton production is continuously threatened by the unpre-dictable changes in climate,specifically high temperatures.Breeding heat-tolerant,high-yielding cotton cultivars with wide adaptability to be grown in the regions with rising temperatures is one of the primary objectives of modern cotton breeding programmes.Therefore,the main objective of the current study is to figure out the effective breed-ing approach to imparting heat tolerance as well as the judicious utilization of commercially significant and stress-tolerant attributes in cotton breeding.Initially,the two most notable heat-susceptible(FH-115 and NIAB Kiran)and tolerant(IUB-13 and GH-Mubarak)cotton cultivars were spotted to develop filial and backcross populations to accom-plish the preceding study objectives.The heat tolerant cultivars were screened on the basis of various morphological(seed cotton yield per plant,ginning turnout percentage),physiological(pollen viability,cell membrane thermostabil-ity)and biochemical(peroxidase activity,proline content,hydrogen peroxide content)parameters.Results The results clearly exhibited that heat stress consequently had a detrimental impact on every studied plant trait,as revealed by the ability of crossing and their backcross populations to tolerate high temperatures.However,when considering overall yield,biochemical,and physiological traits,the IUB-13×FH-115 cross went over particularly well at both normal and high temperature conditions.Moreover,overall seed cotton yield per plant exhibited a posi-tive correlation with both pollen viability and antioxidant levels(POD activity and proline content).Conclusions Selection from segregation population and criteria involving pollen viability and antioxidant levels concluded to be an effective strategy for the screening of heat-tolerant cotton germplasms.Therefore,understanding acquired from this study can assist breeders identifying traits that should be prioritized in order to develop climate resilient cotton cultivars.
基金the National Natural Science Foundation of China(31701369)the China Scholarship Council(201808140009)+1 种基金the Natural Science Foundation of Shanxi Province,China(201701D221218)the Bidding Project of Shanxi Province,China(20191101007)。
文摘The application of Si or K has proven to be beneficial for the growth of plants under saline-alkali stress. However, the synergistic effect of Si and K in improving the growth, ion distribution, and partitioning in Lolium perenne L. under saline-alkali stress remains unclear. In this study, the growth characteristics and ion-selective absorption of ryegrass(Lolium perenne L.) exposed to different levels of saline-alkali stress were evaluated. The growth parameters of ryegrass were significantly improved when Si was applied by itself or coupled with K under low saline-alkali stress. Under a high saline-alkali level, only simultaneous application of Si and K could significantly improve the growth of ryegrass. When Si and K were applied together, the K^(+)/Na^(+) and Ca^(2+)/Na^(+) ratios in root, stem, and leaf of ryegrass were maximally improved as compared to the individual treatments and control. The K^(+) and Ca^(2+) concentrations in the vacuole, cell wall, and organelle of leaf were increased dramatically. This improvement was due to the ability of applied ions to compete with Na^(+), allowing the plant to maintain osmotic potential and leaf water content. The concentration of Na^(+) was significantly reduced when Si and K were applied and mainly concentrated in the soluble fraction and cell wall. The Si concentration in ryegrass increased markedly by the combined application of Si and K, and most of it was accumulated in the cell wall and soluble fraction, which could help in chlorophyll synthesis, reduce membrane injury, and increase water absorption under saline-alkali stress. This study emphasized the advantage of Si and/or K on the growth of plants under different saline-alkaline levels and provided a guide for the production of Si-K fertilizer and its application in saline-alkali soil.
基金the China Scholarship Council (CSC) for financial support
文摘Global demand for vegetable oil is anticipated to double by 2030. The current vegetable oil production platforms, including oil palm and temperate oilseeds, are unlikely to produce such an expansion. Therefore, the exploration of novel vegetable oil sources has become increasingly important in order to make up this future vegetable oil shortfall. Triacylglycerol （TAG）, as the dominant form of vegetable oil, has recently attracted immense interest in terms of being produced in plant vegetative tissues via genetic engineering technologies. Multidiscipline-based ＂-omics＂ studies are increasingly enhancing our understanding of plant lipid biochemistry and metabolism. As a result, the identification of biochemical pathways and the annotation of key genes contributing to fatty acid biosynthesis and to lipid assembly and turnover have been effectively updated. In recent years, there has been a rapid development in the genetic enhancement of TAG accumulation in high-biomass plant vegetative tissues and oilseeds through the genetic manipulation of the key genes and regulators involved in TAG biosynthesis. In this review, current genetic engineering strategies ranging from single-gene manipulation to multigene stacking aimed at increasing plant biomass TAG accumulation are summarized. New directions and suggestions for plant oil production that may help to further alleviate the potential shortage of edible oil and biodiesel are discussed.
基金supported by CSIROthe Cotton Catchment Communities Co-operative Research Centre+1 种基金the Australian Cotton Research and Development Corporation(CRC 1101)the Australian Postgraduate Award.
文摘Background:Plants respond to changes in vapour pressure deficit(VPD)between the leaf and the atmosphere through changes in stomatal response,which can consequently affect transpiration,photosynthesis,and leaf-level water use efficiencies.With projected warmer air temperatures,changes in rainfall distribution and altered VPD in future climates,it is important to understand the potential effect of VPD on leaf-level physiology of field-grown crops.The aim of this study was to assess the impact of altered VPD on leaf-level physiology of field-grown cotton to improve the current understanding of the plant-by-environment interaction,thereby contributing to validation and improvement of physiological and yield response models.Different VPD environments in the field were generated by planting cotton on three dates within the sowing window(early-season(S1)=5th October 2011;mid-season(S2)=9th November 2011;and late-season(S3)=30th November 2011).VPD was also modified by altering crop irrigations.Results:VPDL accounted for the largest proportion of the explained variation in both stomatal conductance(32%∼39%)and photosynthetic(16%∼29%)responses of cotton.Generally,smaller percentages of variation were attributed to other main factors such as the individual plant(Plant),and accumulated temperature stress hours(ASH;a measure of plant water status over time)and interactive factors,including leaf vapour pressure deficit(VPDL)×Plant and Plant×ASH;however,a proportion of variation was unexplained.In addition,the Asat/E(instantaneous transpiration efficiency,ITE)model developed based on cotton grown in the glasshouse was applied to cotton grown in the field.We found that the modelled Asat/E and field-measured Asat/E were very similar,suggesting that the mechanistic basis for ITE was similar in both environments.Conclusions:This study highlights the importance of accounting for VPD in climate change research,given that stomata are highly responsive to changes in VPD.This experiment provides a basis for physiology and production models,particularly in terms of cotton response to projected climatic environments.
文摘Digital maps of soil properties are now widely available.End-users now can access several digital soil mapping(DSM)products of soil properties,produced using different models,calibration/training data,and covariates at various spatial scales from global to local.Therefore,there is an urgent need to provide easy-to-understand tools to communicate map uncertainty and help end-users assess the reliability of DSM products for use at local scales.In this study,we used a large amount of hand-feel soil texture(HFST)data to assess the performance of various published DSM products on the prediction of soil particle size distribution in Central France.We tested four DSM products for soil texture prediction developed at various scales(global,continental,national,and regional)by comparing their predictions with approximately 3200 HFST observations realized on a 1:50000 soil survey conducted after release of these DSM products.We used both visual comparisons and quantitative indicators to match the DSM predictions and HFST observations.The comparison between the low-cost HFST observations and DSM predictions clearly showed the applicability of various DSM products,with the prediction accuracy increasing from global to regional predictions.This simple evaluation can determine which products can be used at the local scale and if more accurate DSM products are required.
基金This work was supported by the National Science Foundation of China(41601307,41771328,41601247 and 41701330)the National Key Research and Development Program of China(2016YFD0200304).
文摘Aims Crop nitrogen(N)and phosphorus(P)stoichiometry can influence food nutritive quality and many ecosystem processes.However,how and why N and P stoichiometry respond to long-term agricul-tural management practices(e.g.N fertilization and film mulching)are not clearly understood.Methods We collected maize tissues(leaf,stem,root and seed)and soil sam-ples from a temperate cropland under 30-year continuous N fer-tilization and plastic film mulching treatments,measured their C,N and P concentrations(the proportion(%)relative to the sample mass),and used structural equation models to uncover the re-sponding mechanisms for crop N and P contents(the total amount(g/m2)in crop biomass).Important Findings Long-term N fertilization increased N concentrations in all crop tissues but sharply decreased P concentrations in vegetative tis-sues(leaf,stem and root),thereby reducing their C/N ratio and increasing C/P and N/P ratios.The drop in P concentration in vegetative tissues was due to the dilution effect by biomass in-crement and the priority of P supply for seed production.In con-trast,film mulching decreased N concentration but increased P concentrations in most crop tissues,thereby increasing C/N ratio and reducing C/P and N/P ratios.Film mulching increased crop P content by increasing soil temperature and moisture;whereas,mulching showed little effect on crop N content,because a posi-tive effects of soil temperature may have canceled out a negative effect by soil moisture.This indicated a decoupling of P and N uptake by crops under film mulching.In conclusion,N fertiliza-tion and plastic film mulching showed opposite effects of on crop N and P stoichiometry.
基金The authors would like to acknowledge the encouragement and funding of project PRJ-010216(formulating broiler diets based on protein and starch digestive dynamics)by AgriFutures Australia(Chicken-meat).
文摘In this study the starch digestion rates in broiler chickens from 18 samples of 5 commonly used feed grains(sorghum,wheat,maize,barley,triticale)were determined.The methodology to determine starch digestion rates in poultry is detailed herein.Starch digestion rates were not significantly different(P-0.128)across the 18 feed grains,which reflects the wide variations that were observed within a given feedstuff.Nevertheless,starch digestion rates in broiler chickens offered wheat-based diets were significantly more rapid by 56.0%(0.117 versus 0.075 min-1;p=0.012)than their sorghum-based counterparts on the basis of a pair-wise comparison.In descending order,the following starch diges-tion rates were observed:wheat(0.117 min-1),barley(0.104 min-1),triticale(0.093 min-1),maize(0.086 min-1),sorghum(0.075 min-1).The implications of these findings are discussed as they almost certainly have implications for poultry nutrition and the development of reduced crude protein diets for broiler chickens.
基金the financial support of the International Postgraduate Research Scholarships and Postgraduate Research Support Scheme of the University of Sydneythe Australian Institute of Nuclear Science and Engineering for providing a research grant(No.ALNGRA15536)for accelerator mass spectrometry14C analysis。
文摘Soil organic carbon(SOC)is the largest terrestrial carbon(C)stock,and the capacity of soils to preserve organic C(OC)varies with many factors,including land use,soil type,and soil depth.We investigated the effect of land use change on soil particulate organic matter(POM)and mineral-associated organic matter(MOM).Surface(0–10 cm)and subsurface(60–70 cm)samples were collected from paired sites(native and cropped)of four contrasting soils.Bulk soils were separated into POM and MOM fractions,which were analyzed for mineralogy,OC,nitrogen,isotopic signatures,and14C.The POM fractions of surface soils were relatively unaffected by land use change,possibly because of the continuous input of crop residues,whereas the POM fractions in corresponding subsurface soils lost more OC.In surface soils,MOM fractions dominated by the oxides of iron and aluminum(oxide-OM)lost more OC than those dominated by phyllosilicates and quartz,which was attributed to diverse organic matter(OM)input and the extent of OC saturation limit of soils.In contrast,oxide-OM fractions were less affected than the other two MOM fractions in the subsurface soils,possibly due to OC protection via organo-mineral associations.The deviations in isotopic signature(linked with vegetation)across the fractions suggested that fresh crop residues constituted the bulk of OM in surface soils(supported by greater14C).Increased isotopic signatures and lower14C in subsurface MOM fractions suggested the association of more microbially processed,aged OC with oxide-OM fractions than with the other MOM fractions.The results reveal that the quantity and quality of OC after land use change is influenced by the nature of C input in surface soils and by mineral-organic association in subsurface soils.
基金funding provided by the Rural Industries Research and Development Corporation Chicken-meat Program for a series of sorghum orientated projects
文摘This review is an outlook for sorghum as a feed grain for broiler chickens based on a survey of relevant stake-holders and recent research outcomes.Australian grain sorghum production will probably continue to generate a harvest in the order of 2.5×10~6t of which some 7.9×10~5t will be used as a feed grain for poultry and pigs.Feed grains are included primarily to provide energy from starch,but energy utilisation by broiler chickens offered sorghum-based diets is relatively inferior,because of incomplete starch digestion.Kafirin,the dominant protein fraction,‘non-tannin’phenolic compounds and phytate are 3‘starch extrinsic’factors in sorghum that compromise starch digestibility and energy utilisation in broiler chickens offered sorghum-based diets.Kafirin concentrations in 6 sorghum varieties were negatively correlated with metabolizable energy to gross energy(ME:GE)ratios(r=0.891;P<0.02)or the efficiency of energy utilisation in broiler chickens.Importantly,kafirin proportions of sorghum protein may be increasing with time in Australia.If so,this represents a fundamental challenge to sorghum breeders which presumably could be met by the development of sorghum varieties with different characteristics,especially in relation to the g-and b-kafirin fractions.White sorghum varieties contain lower polyphenol concentrations which should be advantageous as concentrations of total phenolic compounds were negatively correlated to ME:GE ratios(r=0.838;P<0.04)in 6 sorghum varieties.It would be desirable if more white varieties were to become available.It is suggested that responses to exogenous phytase in birds offered sorghum-based diets would be more robust if sorghum were to contain lower concentrations of kafirin and phenolic compounds.Paradoxically,while better sorghum varieties almost certainly could be developed,it may not necessarily follow that they will command a price premium from poultry and pig producers.
基金the Australia-China Joint Research Centre Program,Healthy Soils for Sustainable Food Production and Environmental Quality(ACSRF48165).
文摘Soil is the foundation for sustainable foodproduction and environmental protection. Created byunsustainable land management practices and a range ofsocial, economic and environmental drivers, soil degrada-tion and pollution have been an ongoing threat tointernational food security and environmental quality.Soil degradation and pollution assessments are, however,often focused on the soil itself with little scope to devisenew soil management approaches that match foodproduction systems and/or environmentalprotection.This study draws lessons from an Australia-China JointResearch Center Program, Healthy Soils for SustainableFood Production and Environmental Quality: a researchplatform that has brought together multi-disciplinaryapproaches fromworld-renowned universitiesandresearch organizations in Australia and China. To thisend, a framework is presented for future soil managementin a new way that combines excellence in research,industry and policymakers in a partnership that will ensurenot only the right focus of the research but also that high-quality outputs will be transferable to industry and end-users.
基金This work was supported by the ARC Discovery project DP190103005 Synergising pedodiversity and soil biodiversity to secure soil functionality。
文摘Human disturbances to soils can lead to dramatic changes in soil physical,chemical,and biological properties.The influence of agricultural activities on the bacterial community over different orders of soil and at depth is still not well understood.We used the concept of genoform and phenoform to investigate the vertical(down to 1 m depth)soil bacterial community structure in paired genosoils(undisturbed forests)and phenosoils(cultivated vineyards)in different soil orders.The study was conducted in the Hunter Valley area,New South Wales,Australia,where samples were collected from 3 different soil orders(Calcarosol,Chromosol,and Kurosol),and each soil order consists of a pair of genosoil and phenosoil.The bacterial community structure was analyzed using highthroughput sequencing of 16S rRNA.Results showed that bacterial-diversity decreased with depth in phenosoils,however,the trend is less obvious in genoform profiles.Topsoil diversity was greater in phenosoils than genosoils,but the trend was reversed in subsoils.Thus,cropping not only affected topsoil bacteria community but also decreased its diversity in the subsoil.Bacterial community in topsoils was influenced by both soil orders and soil forms,however,in subsoils it was more impacted by soil orders.Constrained Analysis of Principal Coordinates revealed that cropping increased the similarity of bacterial structures of different soil orders.This study highlighted the strong influence of agricultural activities on soil microbial distribution with depth,which is controlled by soil order.
