The increase in soil temperature associated with climate change has introduced considerable challenges to crop production.Split nitrogen application(SN)represents a potential strategy for improving crop nitrogen use e...The increase in soil temperature associated with climate change has introduced considerable challenges to crop production.Split nitrogen application(SN)represents a potential strategy for improving crop nitrogen use efficiency and enhancing crop stress resistance.Nevertheless,the precise interaction between soil warming(SW)and SN remains unclear.In order to ascertain the impact of SW on maize growth and whether SN can improve the tolerance of maize to SW,a two-year field experiment was conducted(2022-2023).The aim was to examine the influence of two SW ranges(MT,warming 1.40℃;HT,warming 2.75℃)and two nitrogen application methods(N1,one-time basal application of nitrogen fertilizer;N2,one third of base nitrogen fertilizer+two thirds of jointing stage supplemental nitrogen fertilizer)on maize root growth,photosynthetic characteristics,nitrogen use efficiency,and yield.The results demonstrated that SW impeded root growth and precipitated the premature aging of maize leaves following anthesis,particularly in the HT,which led to a notable reduction in maize yield.In comparison to N1,SN has been shown to increase root length density by 8.54%,root bleeding rate by 8.57%,and enhance root distribution ratio in the middle soil layers(20-60 cm).The interaction between SW and SN had a notable impact on maize growth and yield.The SN improved the absorption and utilization efficiency of nitrogen by promoting root development and downward canopy growth,thus improving the tolerance of maize to SW at the later stage of growth.In particular,the N2HT resulted in a 14.51%increase in the photosynthetic rate,a 18.58%increase in nitrogen absorption efficiency,and a 18.32%increase in maize yield compared with N1HT.It can be posited that the SN represents a viable nitrogen management measure with the potential to enhance maize tolerance to soil high-temperature stress.展开更多
Water use efficiency(WUE),as a pivotal indicator of the coupling degree within the carbon–water cycle of ecosystems,holds considerable importance in assessment of the carbon–water balance within terrestrial ecosyste...Water use efficiency(WUE),as a pivotal indicator of the coupling degree within the carbon–water cycle of ecosystems,holds considerable importance in assessment of the carbon–water balance within terrestrial ecosystems.However,in the context of global warming,WUE evolution and its primary drivers on the Tibetan Plateau remain unclear.This study employed the ensemble empirical mode decomposition method and the random forest algorithm to decipher the nonlinear trends and drivers of WUE on the Tibetan Plateau in 2001–2020.Results indicated an annual mean WUE of 0.8088 gC/mm·m^(2)across the plateau,with a spatial gradient reflecting decrease from the southeast toward the northwest.Areas manifesting monotonous trends of increase or decrease in WUE accounted for 23.64%and 9.69%of the total,respectively.Remarkably,66.67%of the region exhibited trend reversals,i.e.,39.94%of the area of the Tibetan Plateau showed transition from a trend of increase to a trend of decrease,and 26.73%of the area demonstrated a shift from a trend of decrease to a trend of increase.Environmental factors accounted for 70.79%of the variability in WUE.The leaf area index and temperature served as the major driving forces of WUE variation.展开更多
The well-facilitated farmland projects(WFFPs)involve the typical sustainable intensification of farmland use and play a key role in raising food production in China.However,whether such WFFPs can enhance the nitrogen(...The well-facilitated farmland projects(WFFPs)involve the typical sustainable intensification of farmland use and play a key role in raising food production in China.However,whether such WFFPs can enhance the nitrogen(N)use efficiency and reduce environmental impacts is still unclear.Here,we examined the data from 502 valid questionnaires collected from WFFPs in the major grain-producing area,the Huang-Huai-Hai Region(HHHR)in China,with 429 samples for wheat,328 for maize,and 122 for rice.We identified gaps in N use efficiency(NUE)and N losses from the production of the three crops between the sampled WFFPs and counties based on the statistical data.The results showed that compared to the county-level(wheat,39.1%;maize,33.8%;rice,35.1%),the NUEs for wheat(55.2%),maize(52.1%),and rice(50.2%)in the WFFPs were significantly improved(P<0.05).In addition,the intensities of ammonia(NH3)volatilization(9.9-12.2 kg N ha–1),N leaching(6.5-16.9 kg N ha–1),and nitrous oxide(N2O)emissions(1.2-1.6 kg N ha–1)from crop production in the sampled WFFPs were significantly lower than the county averages(P<0.05).Simulations showed that if the N rates are reduced by 10.0,15.0,and 20.0%for the counties,the NUEs of wheat,maize,and rice in the HHHR will increase by 2.9-6.3,2.4-5.2,and 2.6-5.7%,respectively.If the N rate is reduced to the WFFP level in each county,the NUEs of the three crops will increase by 12.9-19.5%,and the N leaching,NH3,and N2O emissions will be reduced by 48.9-56.2,37.4-42.9,and 46.0-66.5%,respectively.Our findings highlight that efficient N management practices in sustainable intensive farmland have considerable potential for reducing environmental impacts.展开更多
In recent years, the rational utilization of saline water resources for agricultural irrigation has emerged as an effective strategy to alleviate water scarcity. To safely and efficiently exploit saline water resource...In recent years, the rational utilization of saline water resources for agricultural irrigation has emerged as an effective strategy to alleviate water scarcity. To safely and efficiently exploit saline water resources over the long term, it is crucial to understand the effects of salinity on crops and develop optimal water-salinity irrigation strategies for processing tomatoes. A two-year field experiment was conducted in 2018 and 2019 to explore the impact of water salinity levels(S1: 1 g L^(–1), S2: 3 g L^(–1), and S3: 5 g L^(–1)) and irrigation amounts(W1: 305 mm, W2: 485 mm, and W3: 611 mm) on the soil volumetric water content and soil salinity, as well as processing tomato growth, yield, and water use efficiency. The results showed that irrigation with low to moderately saline water(<3 g L^(–1)) enhanced plant wateruptake and utilization capacity, with the soil water content(SWC) reduced by 6.5–7.62% and 10.52–13.23% for the S1 and S2 levels, respectively, compared to the S3 level in 2018. Under S1 condition, the soil salt content(SSC) accumulation rate gradually declined with an increase in the irrigation amount. For example, W3 decreased by 85.00 and 77.94% compared with W1 and W2 in 2018, and by 82.60 and 73.68% in 2019, respectively. Leaching effects were observed at the W3 level under S1, which gradually diminished with increasing water salinity and duration. In 2019, the salt contents of soil under each of the treatments increased by 10.81–89.72% compared with the contents in 2018. The yield of processing tomatoes increased with an increasing irrigation amount and peaked in the S1W3 treatment for the two years, reaching 125,304.85 kg ha^(–1)in 2018 and 128,329.71 kg ha^(–1)in 2019. Notably, in the first year, the S2W3 treatment achieved relatively high yields, exhibiting only a 2.85% reduction compared to the S1W3 treatment. However, the yield of the S2W3 treatment declined significantly in two years, and it was 15.88% less than that of the S1W3 treatment. Structural equation modeling(SEM) revealed that soil environmental factors(SWC and SSC) directly influence yield while also exerting indirect impacts on the growth indicators of processing tomatoes(plant height, stem diameter, and leaf area index). The TOPSIS method identified S1W3, S1W2, and S2W2 as the top three treatments. The single-factor marginal effect function also revealed that irrigation water salinity contributed to the composite evaluation scores(CES) when it was below 0.96 g L^(–1). Using brackish water with a salinity of 3 g L^(–1)at an irrigation amount of 485 mm over one year ensured that processing tomatoes maintained high yields with a relatively high CES(0.709). However, using brackish water for more than one year proved unfeasible.展开更多
Elucidating crops'physiological and molecular mechanisms to adapt to low nitrogen environment and promoting nitrogen transfer from senescent leaves to new leaves is crucial in improving Brassica's nitrogen use...Elucidating crops'physiological and molecular mechanisms to adapt to low nitrogen environment and promoting nitrogen transfer from senescent leaves to new leaves is crucial in improving Brassica's nitrogen use efficiency(NUE).Glutamine synthetase gene(GS)plays a vital role in helping plants reassimilate ammonium released from protein degradation in leaves,and it was the focus of our research on this topic.In this study,we identified high(H141)and low(L65)NUE genotypes of Brassica juncea with different responses to low-nitrogen stress.We found that H141 has a lower nitrate content but higher ammonium and free amino acid contents as well as higher nitrate reductase and GS activities in the shoots.These physiological indicators are responsible for the high NUE of H141.Wholegenome resequencing data revealed that 5,880 genes associated with NUE are polymorphic between H141 and L65.These genes participate in various amino acid,carbohydrate,and energy metabolic pathways.Haplotype analysis revealed two haplotypes for BjuB05.GS1.4,Hap1 and Hap2,which have multiple single nucleotide polymorphisms or insertions/deletions in the regulatory regions of the 5′and 3′untranslated regions and introns.Furthermore,the shoot NUE of Hap1 is significantly lower than that of Hap2.These two haplotypes of BjuB05.GS1.4 lead to differences in the shoot NUEs of different genetic populations of mustard and are associated with the local soil nitrogen content,suggesting that they might help mustard to adapt to different geographic localities.In conclusion,the results of our study shed light on the physiological and molecular mechanisms underlying different mustard NUE genotypes and demonstrate the enormous potential of NUE breeding in B.juncea.展开更多
The distributions of light and nitrogen within a plant's canopy reflect the growth adaptation of crops to the environment and are conducive to improving the carbon assimilation ability.So can the yield in crop pro...The distributions of light and nitrogen within a plant's canopy reflect the growth adaptation of crops to the environment and are conducive to improving the carbon assimilation ability.So can the yield in crop production be maximized by improving the light and nitrogen distributions without adding any additional inputs?In this study,the effects of different nitrogen application rates and planting densities on the canopy light and nitrogen distributions of two highyielding maize cultivars(XY335 and DH618)and the regulatory effects of canopy physiological characteristics on radiation use efficiency(RUE)and yield were studied based on high-yield field experiments in Qitai,Xinjiang Uygur Autonomous Region,China,during 2019 and 2020.The results showed that the distribution of photosynthetically active photon flux density(PPFD)in the maize canopy decreased from top to bottom,while the vertical distribution of specific leaf nitrogen(SLN)initially increased and then decreased from top to bottom in the canopy.When SLN began to decrease,the PPDF values of XY335 and DH618 were 0.5 and 0.3,respectively,corresponding to 40.6 and49.3%of the total leaf area index(LAI).Nitrogen extinction coefficient(K_(N))/light extinction coefficient(K_(L))ratio in the middle and lower canopy of XY335(0.32)was 0.08 higher than that of DH618(0.24).The yield and RUE of XY335(17.2 t ha^(-1)and 1.8g MJ^(-1))were 7.0%(1.1 t ha^(-1))and 13.7%(0.2 g MJ^(-1))higher than those of DH618(16.1 t ha^(-1)and 1.6 g MJ^(-1)).Therefore,better light conditions(where the proportion of LAI in the upper and middle canopy was small)improved the light distribution when SLN started to decline,thus helping to mobilize the nitrogen distribution and maintain a high K_(N)and K_(N)/K_(L)ratio.In addition,K_(N)/K_(L)was a key parameter for yield improvement when the maize nutrient requirements were met at 360 kg N ha^(-1).At this level,an appropriately optimized high planting density could promote nitrogen utilization and produce higher yields and greater efficiency.The results of this study will be important for achieving high maize yields and the high efficiency cultivation and breeding of maize in the future.展开更多
Stable carbon isotopes(δ^(13)C)are extensively utilized to study intrinsic water use efficiency(iWUE)at the leaf-scale in terrestrial ecosystems,serving as a crucial metric for assessing plant adaptation to climate c...Stable carbon isotopes(δ^(13)C)are extensively utilized to study intrinsic water use efficiency(iWUE)at the leaf-scale in terrestrial ecosystems,serving as a crucial metric for assessing plant adaptation to climate change.However,there is currently a lack of consensus regarding the leaf-scale iWUE variation characteristics among different functional types.In this study,we measured theδ^(13)Cleaf and iWUE values of different functional plants(i.e.,life forms,leaf types,and mycorrhizal types)from 120 species across distinct habitat types(i.e.,hillside,nearpeak,and peak)in a subtropical forest on the western slope of Wuyi Mountains,southern China.The results showed that theδ^(13)Cleaf values of plants on the western slope of Wuyi Mountains ranged from-34.63‰to-30.04‰,and iWUE ranged from 5.93μmol mol^(-1)to 57.34μmol mol^(-1).Theδ^(13)Cleaf and iWUE values differed significantly among plant life forms,following the order of herbs>vine plants>shrubs>trees.Theδ^(13)Cleaf and iWUE values of ectomycorrhizal(ECM)species were greater than those of arbuscular mycorrhizal(AM)species despite there being no significant difference between plants with different leaf types(Simple leaves(SL)vs.Compound leaves(CL)).From the hillside to the peak,both at the community level and at the species level,theδ^(13)C values of leaves and iWUE values of plants exhibited an upward trend.The regression analysis revealed that leaf-scale iWUE was significantly negatively correlated with soil water content and significantly positively correlated with leaf phosphorus content.The findings indicated that leaf carbon isotope fractionation and corresponding iWUE can be influenced by life form,mycorrhizal type,and soil water availability.These insights provide a deeper understanding of the coupling mechanisms of carbon,water,and nutrients among different functional plant types in subtropical forests,and offer insights into predicting plant adaptability under climate change.展开更多
Gross primary production(GPP)is a crucial indicator representing the absorption of atmospheric CO_(2) by vegetation.At present,the estimation of GPP by remote sensing is mainly based on leaf-related vegetation indexes...Gross primary production(GPP)is a crucial indicator representing the absorption of atmospheric CO_(2) by vegetation.At present,the estimation of GPP by remote sensing is mainly based on leaf-related vegetation indexes and leaf-related biophysical para-meter leaf area index(LAI),which are not completely synchronized in seasonality with GPP.In this study,we proposed chlorophyll content-based light use efficiency model(CC-LUE)to improve GPP estimates,as chlorophyll is the direct site of photosynthesis,and only the light absorbed by chlorophyll is used in the photosynthetic process.The CC-LUE model is constructed by establishing a linear correlation between satellite-derived canopy chlorophyll content(Chlcanopy)and FPAR.This method was calibrated and validated utiliz-ing 7-d averaged in-situ GPP data from 14 eddy covariance flux towers covering deciduous broadleaf forest ecosystems across five dif-ferent climate zones.Results showed a relatively robust seasonal consistency between Chlcanopy with GPP in deciduous broadleaf forests under different climatic conditions.The CC-LUE model explained 88% of the in-situ GPP seasonality for all validation site-year and 56.0% of in-situ GPP variations through the growing season,outperforming the three widely used LUE models(MODIS-GPP algorithm,Vegetation Photosynthesis Model(VPM),and the eddy covariance-light use efficiency model(EC-LUE)).Additionally,the CC-LUE model(RMSE=0.50 g C/(m^(2)·d))significantly improved the underestimation of GPP during the growing season in semi-arid region,re-markably decreasing the root mean square error of averaged growing season GPP simulation and in-situ GPP by 75.4%,73.4%,and 37.5%,compared with MOD17(RMSE=2.03 g C/(m^(2)·d)),VPM(RMSE=1.88 g C/(m^(2)·d)),and EC-LUE(RMSE=0.80 g C/(m^(2)·d))model.The chlorophyll-based method proved superior in capturing the seasonal variations of GPP in forest ecosystems,thereby provid-ing the possibility of a more precise depiction of forest seasonal carbon uptake.展开更多
Understanding the relationship between forest management and water use efficiency(WUE)is important for evaluating forest adaptability to climate change.However,the effects of thinning and understory removal on WUE and...Understanding the relationship between forest management and water use efficiency(WUE)is important for evaluating forest adaptability to climate change.However,the effects of thinning and understory removal on WUE and its key controlling processes are not well understood,which limits our comprehension of the physiological mechanisms of various management practices.In this study,four forest management measures(no thinning:NT;understory removal:UR;light thinning:LT;and heavy thinning:HT)were carried out in Pinus massoniana plantations in a subtropical region of China.Photosynthetic capacity and needle stable carbon isotope composition(δ^(13)C)were measured to assess instantaneous water use efficiency(WUE_(inst))and long-term water use efficiency(WUE_(i)).Multiple regression models and structural equation modelling(SEM)identified the effects of soil properties and physiological performances on WUE_(inst)and WUE_(i).The results show that WUE_(inst)values among the four treatments were insignificant.However,compared with the NT stand(35.8μmol·mol^(-1)),WUE_(i)values significantly increased to 41.7μmol·mol^(-1)in the UR,50.1μmol·mol^(-1)in the LT and 46.6μmol·mol^(-1)in HT treatments,largely explained by photosynthetic capacity and soil water content.Understory removal did not change physiological performance(needle water potential and photosynthetic capacity).Thinning increased the net photosynthetic rate(A_n)but not stomatal conductance(g_s)or predawn needle water potential(ψ_(pd)),implying that the improvement in water use efficiency for thinned stands was largely driven by radiation interception than by soil water availability.In general,thinning may be an appropriate management measure to promote P.massoniana WUE to cope with seasonal droughts under future extreme climates.展开更多
Controlled-release urea(CRU)is commonly used to improve the crop yield and nitrogen use efficiency(NUE).However,few studies have investigated the effects of CRU in the ratoon rice system.Ratoon rice is the practice of...Controlled-release urea(CRU)is commonly used to improve the crop yield and nitrogen use efficiency(NUE).However,few studies have investigated the effects of CRU in the ratoon rice system.Ratoon rice is the practice of obtaining a second harvest from tillers originating from the stubble of the previously harvested main crop.In this study,a 2-year field experiment using a randomized complete block design was conducted to determine the effects of CRU on the yield,NUE,and economic benefits of ratoon rice,including the main crop,to provide a theoretical basis for fertilization of ratoon rice.The experiment included four treatments:(i)no N fertilizer(CK);(ii)traditional practice with 5 applications of urea applied at different crop growth stages by surface broadcasting(FFP);(iii)one-time basal application of CRU(BF1);and(iv)one-time basal application of CRU combined with common urea(BF2).The BF1 and BF2 treatments significantly increased the main crop yield by 17.47 and 15.99%in 2019,and by 17.91 and 16.44%in 2020,respectively,compared with FFP treatment.The BF2 treatment achieved similar yield of the ratoon crop to the FFP treatment,whereas the BF1 treatment significantly increased the yield of the ratoon crop by 14.81%in 2019 and 12.21%in 2020 compared with the FFP treatment.The BF1 and BF2 treatments significantly improved the 2-year apparent N recovery efficiency,agronomic NUE,and partial factor productivity of applied N by 11.47-16.66,27.31-44.49,and 9.23-15.60%,respectively,compared with FFP treatment.The BF1 and BF2 treatments reduced the chalky rice rate and chalkiness of main and ratoon crops relative to the FFP treatment.Furthermore,emergy analysis showed that the production efficiency of the BF treatments was higher than that of the FFP treatment.The BF treatments reduced labor input due to reduced fertilization times and improved the economic benefits of ratoon rice.Compared with the FFP treatment,the BF1 and BF2 treatments increased the net income by 14.21-16.87 and 23.76-25.96%,respectively.Overall,the one-time blending use of CRU and common urea should be encouraged to achieve high yield,high nitrogen use efficiency,and good quality of ratoon rice,which has low labor input and low apparent N loss.展开更多
Wolfberry(Lycium barbarum L.)is important for health care and ecological protection.However,it faces problems of low productivity and resource utilization during planting.Exploring reasonable models for water and nitr...Wolfberry(Lycium barbarum L.)is important for health care and ecological protection.However,it faces problems of low productivity and resource utilization during planting.Exploring reasonable models for water and nitrogen management is important for solving these problems.Based on field trials in 2021 and 2022,this study analyzed the effects of controlling soil water and nitrogen application levels on wolfberry height,stem diameter,crown width,yield,and water(WUE)and nitrogen use efficiency(NUE).The upper and lower limits of soil water were controlled by the percentage of soil water content to field water capacity(θ_(f)),and four water levels,i.e.,adequate irrigation(W0,75%-85%θ_(f)),mild water deficit(W1,65%-75%θ_(f)),moderate water deficit(W2,55%-65%θ_(f)),and severe water deficit(W3,45%-55%θ_(f))were used,and three nitrogen application levels,i.e.,no nitrogen(N0,0 kg/hm^(2)),low nitrogen(N1,150 kg/hm^(2)),medium nitrogen(N2,300 kg/hm^(2)),and high nitrogen(N3,450 kg/hm^(2))were implied.The results showed that irrigation and nitrogen application significantly affected plant height,stem diameter,and crown width of wolfberry at different growth stages(P<0.01),and their maximum values were observed in W1N2,W0N2,and W1N3 treatments.Dry weight per plant and yield of wolfberry first increased and then decreased with increasing nitrogen application under the same water treatment.Dry weight per hundred grains and dry weight percentage increased with increasing nitrogen application under W0 treatment.However,under other water treatments,the values first increased and then decreased with increasing nitrogen application.Yield and its component of wolfberry first increased and then decreased as water deficit increased under the same nitrogen treatment.Irrigation water use efficiency(IWUE,8.46 kg/(hm^(2)·mm)),WUE(6.83 kg/(hm^(2)·mm)),partial factor productivity of nitrogen(PFPN,2.56 kg/kg),and NUE(14.29 kg/kg)reached their highest values in W2N2,W1N2,W1N2,and W1N1 treatments.Results of principal component analysis(PCA)showed that yield,WUE,and NUE were better in W1N2 treatment,making it a suitable water and nitrogen management mode for the irrigation area of the Yellow River in the Gansu Province,China and similar planting areas.展开更多
The effect of urban shrinkage has gradually become a new topic.Theoretically,urban shrinkage may exert great influence on land use efficiency(LUE)through various urban subsystems,but there is currently limited researc...The effect of urban shrinkage has gradually become a new topic.Theoretically,urban shrinkage may exert great influence on land use efficiency(LUE)through various urban subsystems,but there is currently limited research examining these pathways.Using the Super-SBM-Undesirable model and the Structural Equation Model(SEM),this study calculates the LUE of shrinking cities in Northeast China and simulates the process of urban shrinkage affecting LUE.To quantify the process of urban shrinkage affecting LUE,three mediation variables,namely the economy,public services,and innovation,are used as latent variables to apply SEM.The results show that urban shrinkage will affect LUE through a direct path and indirect paths.In the direct path,urban shrinkage leads to an improvement in LUE.In the indirect paths,the economy and innovation will transmit the negative effect of urban shrinkage on LUE,while public services will reverse this effect.An important contribution of this study is that it quantifies the paths of urban shrinkage affecting LUE,thereby expanding the understanding of urban shrinkage effect and laying a foundation for the sustainable development of shrinking cities.展开更多
The joint study of agriculture and rural areas is of great significance for safeguarding agricultural development,revitalizing rural areas,and enhancing farmers'well-being.This paper aims to assess the spatiotempo...The joint study of agriculture and rural areas is of great significance for safeguarding agricultural development,revitalizing rural areas,and enhancing farmers'well-being.This paper aims to assess the spatiotemporal evolution characteristics of the coupling and coordination degree of agricultural resilience and rural land use efficiency and their dynamic transfer law and driving mechanisms,based on panel data of 31 provinces(municipalities and autonomous regions)in China from 2010 to 2020.The results showed:(1)Good coupling and coordination of agricultural resilience and rural land use efficiency,with reduced temporal differentiation degrees between regions;(2)Significant spatial autocorrelation between the overall coupling and coordination degrees of agricultural resilience and rural land use efficiency,forming cold spot and hot spot spatial patterns in the western and eastern parts,respectively,with a central transition area;(3)A spillover effect of the dynamic transfer process,with a manifested specific law as"club convergence","Matthew effect",and progressive development characteristics;(4)The key roles of the natural,social,economic,and policy indicators in the coupling and coordination development process of agricultural resilience and rural land use efficiency.However,the selected indicators showed substantial spatial differences in their influences on the coupling and coordination process between provinces.展开更多
Double-cropping rice in South China continues to break the total yield record,but the yield potential of singlecropping rice is not being realized.Radiation use efficiency(RUE)has been singled out as an important dete...Double-cropping rice in South China continues to break the total yield record,but the yield potential of singlecropping rice is not being realized.Radiation use efficiency(RUE)has been singled out as an important determinant of grain yield in many cereal species.However,there is no information on whether the yield gaps in doublecropping rice involve differences in RUE.Field experiments were performed over two years to evaluate the effects of intercepted radiation(IP)and RUE on the above-ground biomass production,crop growth rate(CGR),and harvest index(HI),in four representative rice varieties,i.e.,Xiangyaxiangzhan(XYXZ),Meixiangzhan 2(MXZ2),Nanjingxiangzhan(NJXZ),and Ruanhuayoujinsi(RHYJS),during the early and late seasons of rice cultivation in South China.The results revealed that grain yield in the early season was 8.2%higher than in the late season.The yield advantage in the early season was primarily due to higher spikelets per panicle and above-ground biomass resulting from a higher RUE.The spikelets per panicle in the early season were 6.5,8.3,6.9,and 8.5%higher in XYXZ,MXZ2,NJXZ,and RHYJS,respectively,than in the late season.The higher early season grain yield was more closely related to RUE in the middle tillering stage(R^(2)=0.34),panicle initiation(R^(2)=0.16),and maturation stage(R^(2)=0.28),and the intercepted photosynthetically active radiation(IPAR)in the maturation stage(R^(2)=0.28),while the late season grain yield was more dependent on IPAR in the middle tillering stage(R^(2)=0.31)and IPAR at panicle initiation(R^(2)=0.23).The results of this study conclusively show that higher RUE contributes to the yield progress of early season rice,while the yield improvement of late season rice is attributed to higher radiation during the early reproductive stage.Rationally allocating the RUE of double-cropping rice with high RUE varieties or adjustments of the sowing period merits further study.展开更多
Camellia petelotii(Merr.)Sealy is an endangered Chinese native species that originates from Guangxi Zhuang Autonomous Region,China.Previous research demonstrated that proper water and fertilizer treatments could impro...Camellia petelotii(Merr.)Sealy is an endangered Chinese native species that originates from Guangxi Zhuang Autonomous Region,China.Previous research demonstrated that proper water and fertilizer treatments could improve the growth and quality of Camellia species.This study uses a three-factor,five-level quadratic rotational combination experimental design to investigate the impact of water-fertilizer coupling on plant growth character-istics and the most suitable treatment for 24-month-old grafted C.petelotii seedlings.The experimental design includes irrigation levels[30%,40%,55%,70%,80%offield capacity(FC)],nitrogen application(0,2.17,5.43,8.70,10.87 g·plant^(-1)),and phosphorus application(0,0.96,2.40,3.85,4.81 g·plant^(-1)).The results indicated that:(1)Water-nitrogen and water-phosphorus interactions significantly affected ground diameter,chlorophyll content and specific leaf weight(SLW),while water-nitrogen interactions significantly affected plant height and photo-synthesis;(2)Application of nitrogen(8.70 g·plant^(-1))and phosphorus(3.85 g·plant^(-1))fertilizers under appropri-ate irrigation conditions(40%FC and 70%FC)improved growth.Applying fertilizers containing either nitrogen(10.87 g·plant^(-1))or phosphorus(4.81 g·plant^(-1))under adequate irrigation(55%FC)increased the Chl content.However,high nitrogen levels(10.87 g·plant^(-1))reduced photosynthesis.Conversely,it was enhanced under appropriate phosphorus(4.81 g·plant^(-1))when the irrigation level was 55%FC,indicating the sensitivity of C.pete-lotii seedlings to nitrogen fertilizer.(3)Under specific conditions of 40%FC or 70%FC irrigation and 8.70 g·plant^(-1) or 2.17 g·plant^(-1) nitrogen fertilizer application,3.85 g·plant^(-1) phosphorus addition boosted the SLW whereas,0.96 g·plant^(-1) phosphorus addition inhibited it.Under W=55%FC,deficiencies in either nitrogen(N=0 g·plant^(-1))or phosphorus(P=0 g·plant^(-1))significantly decreased leaf growth,affecting SLW.In summary,C.petelotii was more sensitive to nitrogen fertilizer at W=55%FC,and nitrogen deficiency inhibited C.petelotii growth in terms of ground diameter more than phosphorus deficiency.The C.petelotii seedlings performed best when treated with 55%FC,5.43 g·plant^(-1) nitrogen,2.40 g·plant^(-1) phosphorus per plant.These parameter esti-mates could optimize water and fertilizer application for C.petelotii seedlings.展开更多
Whole_growing season pot experiments were conducted to examine the response of growth and water use efficiency ( WUE ) of spring wheat ( Triticum aestivum L. cv. Gaoyuan 602) to CO 2 enrichment. Wheat plants wer...Whole_growing season pot experiments were conducted to examine the response of growth and water use efficiency ( WUE ) of spring wheat ( Triticum aestivum L. cv. Gaoyuan 602) to CO 2 enrichment. Wheat plants were grown in open_top chambers (OTCs) subject to two concentrations of CO 2 ()(350 and 700 μL/L, hereafter 'ambient' and 'elevated' respectively) and three soil water levels (80%, 60% and 40% field water capacity ( FWC ), hereafter 'high soil moisture', 'medium soil moisture' and 'low soil moisture' respectively). Elevated CO 2 greatly increased leaf net photosynthesis ( Pn ) at all three soil water levels. The Pn of plants growing under elevated was 22% lower than that of plants growing at ambient when measured with the same (700 μL/L). Plant growth was enhanced by elevated throughout the growing season, with an increase of 14.8% in shoot dry weight at harvest under high soil moisture, and leaf area was increased by about 20% at all three soil water levels. Elevated in combination with high soil moisture increased the ratio of plant shoot dry weight to height by 15.7%, while this ratio was decreased by over 50% when plants were subject to drought. Elevated also increased the water use efficiency of wheat, mainly due to decreases in transpiration and cumulative consumption of water, and an increase in shoot dry weight, with the biggest value of 30% occurring at high soil water moisture level. Compared to high soil moisture, drought decreased shoot dry weight by 72% under ambient , and by 76% under elevated . Similarly, drought also reduced WUE by 19% under ambient , and 23% under elevated . Our results indicate that: (1) elevated can increase the photosynthetic rates, growth and WUE of wheat plants; (2) long_term exposure to high may result in lower photosynthetic capacity; (3) high stimulates plants lateral growth more than vertical growth; (4) the effects of CO 2 enrichment on plants depend on soil water status, with plants benefiting more from CO 2 enrichment if sufficient water is supplied; and (5) drought may cause relatively more reduction in plant growth and WUE under future elevated conditions.展开更多
[Objective] The aim of this study was to investigate the impacts of slow and controlled release fertilizers（SCRF）on the yield of qiubei hot pepper,its nutrient use efficiency and environment.[Method] Using Qiubei ho...[Objective] The aim of this study was to investigate the impacts of slow and controlled release fertilizers（SCRF）on the yield of qiubei hot pepper,its nutrient use efficiency and environment.[Method] Using Qiubei hot pepper（Capsicum frutescens L.）as the experimental material,we studied the fertilization effect and environment-protecting effect of SCRF.[Result] The result showed that SCRF could improve the agronomic characteristics of hot pepper.Compared to singly applied common fertilizers,SCRF increased economic yield by 20.90% and economic benefit by 13 234.35 Yuan/hm2,and the ratio of output to input was improved by 47.93%.In comparison with common straight fertilizers at same NPK proportion and rate,SCRF increased economic yield by 5.26% and economic benefit by 5 554.80 Yuan/hm2,and the ratio of output to input was improved by 9.91%.Under the reduced use of SCRF by 20%,SCRF increased economic yield by 12.38% and economic benefit by 9595.20 Yuan/hm2 compared with singly applied common fertilizers,and the ratio of output to input was improved by 65.95%.SCRF improved nitrogen,phosphorus and potassium use efficiencies by 12.42-17.53,3.35-5.24 and 5.37-14.02 percents respectively.[Conclusion] As the result of much reduced N and P application rates,SCRF would significantly economize fertilizer resources and minimize the pollution caused by the loss of fertilizer nutrients,which is of practical importance for environment protection.展开更多
Major plant species in the Xilin River Basin were grouped into six plant functional groups (PFGs) based on their water ecological groups: xerophytes, mesoxerophytes, xeromesophytes, mesophytes, hygromesophytes and hyg...Major plant species in the Xilin River Basin were grouped into six plant functional groups (PFGs) based on their water ecological groups: xerophytes, mesoxerophytes, xeromesophytes, mesophytes, hygromesophytes and hygrophytes. We surveyed the composition, delta(13)C values and proline concentration of PFGs in eight different plant communities along a soil moisture gradient. Results show that: (1) PFGs occurred variously in eight steppe communities with different soil moisture status. In wetter habitats, hygromesophytes and hygrophytes were more abundant and accounted for the majority of aboveground biomass, whereas xerophytes and mesoxerophytes became more conspicuous in dryer habitats; (2) the numerical order of the mean delta(13)C values of PFGs is as follows: xerophytes (-26.38parts per thousand) = mesoxerophytes (-26.51parts per thousand) > xeromesophytes (-27.02parts per thousand) > mesophytes (-27.56parts per thousand) = hygromesophytes and hygrophytes (-27.80parts per thousand); (3) xerophytes maintained relative higher delta(13)C values and water use efficiency (WUE) in habitats of different water availability, whereas delta(13)C values of xeromesophytes were more sensitive to change in soil water availability; (4) From xerophytes to hygrophytes, their proline content markedly increased. Significantly positive correlations existed between proline and biomass or delta(13)C values of different water ecological groups.展开更多
Photosynthesis ( P n ), transpiration ( E ) and water use efficiency ( WUE ) of more than 66 arid sand species from different environmental habitats, shifting sand dune, fixed sand dune, lowland and wetland in ...Photosynthesis ( P n ), transpiration ( E ) and water use efficiency ( WUE ) of more than 66 arid sand species from different environmental habitats, shifting sand dune, fixed sand dune, lowland and wetland in the Maowusu Sand Area were analyzed and the relation among these characteristics and the resource utilization efficiency, taxonomic categories and growth forms of the species were assessed. The results showed that species from Chenopodiaceae, Gramineae, Leguminosae which possessed the C 4 photosynthesis pathway, or C 3 pathway and also with nitrogen_fixation capacities had higher or the highest P n values, i.e., 20～30 μmol CO 2·m -2 ·s -1 , while that of evergreen shrub of Pinaceae had the lowest P n values, i.e., 0～5 μmol CO 2·m -2 ·s -1 . Those species from Compositae, Scrophulariaceae, and Gramineae with C 3 pathway but no N_fixation capacity had the highest E rates, i.e., 20～30 mmol H 2O·m -2 ·s -1 and again the evergreen shrub together with some species from Salicaceae and Compositae had the lowest E rates, i.e., 0～5 mmol H 2O·m -2 ·s -1 . Species from Leguminosae, Gramineae and Chenopodiaceae with C 4 pathway or C 3 pathway with N_fixation capacity, both shrubs and grasses, generally had higher WUE . However, even the physiological traits of the same species were habitat_ and season_specific. The values of both P n and E in late summer were much higher than those in early summer, with average increases of 26%, 40% respectively in the four habitats. WUE in late summer was, however, 12% lower. Generally, when the environments became drier as a result of habitats changed, i.e., in the order of wetland, lowland, fixed sand dune and shifting sand dune, P n and E decreased but WUE increased.展开更多
[Objective] The aim was to study the effects of slow release fertilizer on the yield,economic benefit and nutrient use efficiency of carnation and environmental pollution.[Method] Taking carnation（Dianthus caryophyl...[Objective] The aim was to study the effects of slow release fertilizer on the yield,economic benefit and nutrient use efficiency of carnation and environmental pollution.[Method] Taking carnation（Dianthus caryophyllus）as research object,the application effect and environmental protection effect of slow release fertilizer on carnation were discussed through field plot test.[Result] The main agronomic characters of carnation improved after the application of slow release fertilizer;compared with Conv-F treatment,the yield of carnation with slow release fertilizer increased by 18.67%-20.83%,and its economic benefit increased by 105 500 yuan/hm2,while the ratio of output to input improved by 74.29%;under the same NPK ratio and nutrient amount,the yield,economic benefit and ratio of output to input of carnation after the application of slow release fertilizer increased by 2.11%,14 800 yuan and 16.2%,respectively;besides,the application of slow release fertilizer improved the nutrient use efficiency of carnation,and N,P and K nutrient use efficiency in Opt-F-0.7% treatment increased by 13.88%,8.57% and 30.14% compared with Conv-F treatment.[Conclusion] Slow release fertilizer could not only reduce the waste of fertilizer resources and improve fertilizer use efficiency but also decrease the pollution caused by nutrient loss,which had important practical significance for protecting ecological environment and promoting the sustainable development of agriculture.展开更多
基金supported by the Natural Science Fund of China(31771724)the Key Research and Development Project of Shaanxi Province(2024NC-ZDCYL-01-10).
文摘The increase in soil temperature associated with climate change has introduced considerable challenges to crop production.Split nitrogen application(SN)represents a potential strategy for improving crop nitrogen use efficiency and enhancing crop stress resistance.Nevertheless,the precise interaction between soil warming(SW)and SN remains unclear.In order to ascertain the impact of SW on maize growth and whether SN can improve the tolerance of maize to SW,a two-year field experiment was conducted(2022-2023).The aim was to examine the influence of two SW ranges(MT,warming 1.40℃;HT,warming 2.75℃)and two nitrogen application methods(N1,one-time basal application of nitrogen fertilizer;N2,one third of base nitrogen fertilizer+two thirds of jointing stage supplemental nitrogen fertilizer)on maize root growth,photosynthetic characteristics,nitrogen use efficiency,and yield.The results demonstrated that SW impeded root growth and precipitated the premature aging of maize leaves following anthesis,particularly in the HT,which led to a notable reduction in maize yield.In comparison to N1,SN has been shown to increase root length density by 8.54%,root bleeding rate by 8.57%,and enhance root distribution ratio in the middle soil layers(20-60 cm).The interaction between SW and SN had a notable impact on maize growth and yield.The SN improved the absorption and utilization efficiency of nitrogen by promoting root development and downward canopy growth,thus improving the tolerance of maize to SW at the later stage of growth.In particular,the N2HT resulted in a 14.51%increase in the photosynthetic rate,a 18.58%increase in nitrogen absorption efficiency,and a 18.32%increase in maize yield compared with N1HT.It can be posited that the SN represents a viable nitrogen management measure with the potential to enhance maize tolerance to soil high-temperature stress.
基金National Nonprofit Institute Research Grant of CAF,No.CAFYBB2018ZA004,No.CAFYBB2023ZA009Fengyun Application Pioneering Project,No.FY-APP-ZX-2023.02。
文摘Water use efficiency(WUE),as a pivotal indicator of the coupling degree within the carbon–water cycle of ecosystems,holds considerable importance in assessment of the carbon–water balance within terrestrial ecosystems.However,in the context of global warming,WUE evolution and its primary drivers on the Tibetan Plateau remain unclear.This study employed the ensemble empirical mode decomposition method and the random forest algorithm to decipher the nonlinear trends and drivers of WUE on the Tibetan Plateau in 2001–2020.Results indicated an annual mean WUE of 0.8088 gC/mm·m^(2)across the plateau,with a spatial gradient reflecting decrease from the southeast toward the northwest.Areas manifesting monotonous trends of increase or decrease in WUE accounted for 23.64%and 9.69%of the total,respectively.Remarkably,66.67%of the region exhibited trend reversals,i.e.,39.94%of the area of the Tibetan Plateau showed transition from a trend of increase to a trend of decrease,and 26.73%of the area demonstrated a shift from a trend of decrease to a trend of increase.Environmental factors accounted for 70.79%of the variability in WUE.The leaf area index and temperature served as the major driving forces of WUE variation.
基金supported by the National Key Research and Development Program of China(2022YFB3903505)the National Natural Science Foundation of China(72221002)。
文摘The well-facilitated farmland projects(WFFPs)involve the typical sustainable intensification of farmland use and play a key role in raising food production in China.However,whether such WFFPs can enhance the nitrogen(N)use efficiency and reduce environmental impacts is still unclear.Here,we examined the data from 502 valid questionnaires collected from WFFPs in the major grain-producing area,the Huang-Huai-Hai Region(HHHR)in China,with 429 samples for wheat,328 for maize,and 122 for rice.We identified gaps in N use efficiency(NUE)and N losses from the production of the three crops between the sampled WFFPs and counties based on the statistical data.The results showed that compared to the county-level(wheat,39.1%;maize,33.8%;rice,35.1%),the NUEs for wheat(55.2%),maize(52.1%),and rice(50.2%)in the WFFPs were significantly improved(P<0.05).In addition,the intensities of ammonia(NH3)volatilization(9.9-12.2 kg N ha–1),N leaching(6.5-16.9 kg N ha–1),and nitrous oxide(N2O)emissions(1.2-1.6 kg N ha–1)from crop production in the sampled WFFPs were significantly lower than the county averages(P<0.05).Simulations showed that if the N rates are reduced by 10.0,15.0,and 20.0%for the counties,the NUEs of wheat,maize,and rice in the HHHR will increase by 2.9-6.3,2.4-5.2,and 2.6-5.7%,respectively.If the N rate is reduced to the WFFP level in each county,the NUEs of the three crops will increase by 12.9-19.5%,and the N leaching,NH3,and N2O emissions will be reduced by 48.9-56.2,37.4-42.9,and 46.0-66.5%,respectively.Our findings highlight that efficient N management practices in sustainable intensive farmland have considerable potential for reducing environmental impacts.
基金funded by the National Key R&D Program of China (2022YFD1900405)。
文摘In recent years, the rational utilization of saline water resources for agricultural irrigation has emerged as an effective strategy to alleviate water scarcity. To safely and efficiently exploit saline water resources over the long term, it is crucial to understand the effects of salinity on crops and develop optimal water-salinity irrigation strategies for processing tomatoes. A two-year field experiment was conducted in 2018 and 2019 to explore the impact of water salinity levels(S1: 1 g L^(–1), S2: 3 g L^(–1), and S3: 5 g L^(–1)) and irrigation amounts(W1: 305 mm, W2: 485 mm, and W3: 611 mm) on the soil volumetric water content and soil salinity, as well as processing tomato growth, yield, and water use efficiency. The results showed that irrigation with low to moderately saline water(<3 g L^(–1)) enhanced plant wateruptake and utilization capacity, with the soil water content(SWC) reduced by 6.5–7.62% and 10.52–13.23% for the S1 and S2 levels, respectively, compared to the S3 level in 2018. Under S1 condition, the soil salt content(SSC) accumulation rate gradually declined with an increase in the irrigation amount. For example, W3 decreased by 85.00 and 77.94% compared with W1 and W2 in 2018, and by 82.60 and 73.68% in 2019, respectively. Leaching effects were observed at the W3 level under S1, which gradually diminished with increasing water salinity and duration. In 2019, the salt contents of soil under each of the treatments increased by 10.81–89.72% compared with the contents in 2018. The yield of processing tomatoes increased with an increasing irrigation amount and peaked in the S1W3 treatment for the two years, reaching 125,304.85 kg ha^(–1)in 2018 and 128,329.71 kg ha^(–1)in 2019. Notably, in the first year, the S2W3 treatment achieved relatively high yields, exhibiting only a 2.85% reduction compared to the S1W3 treatment. However, the yield of the S2W3 treatment declined significantly in two years, and it was 15.88% less than that of the S1W3 treatment. Structural equation modeling(SEM) revealed that soil environmental factors(SWC and SSC) directly influence yield while also exerting indirect impacts on the growth indicators of processing tomatoes(plant height, stem diameter, and leaf area index). The TOPSIS method identified S1W3, S1W2, and S2W2 as the top three treatments. The single-factor marginal effect function also revealed that irrigation water salinity contributed to the composite evaluation scores(CES) when it was below 0.96 g L^(–1). Using brackish water with a salinity of 3 g L^(–1)at an irrigation amount of 485 mm over one year ensured that processing tomatoes maintained high yields with a relatively high CES(0.709). However, using brackish water for more than one year proved unfeasible.
基金supported by the National Natural Science Foundation of China(U21A20236,32072664)the Natural Science Foundation of Hunan Province,China(2022RC3053,2021JC0001,2021RC3086,2022NK2009)+1 种基金the China Agriculture Research System(CARS-01-30)the Innovation Foundation for Graduate of Hunan Agricultural University,China(2023XC116)。
文摘Elucidating crops'physiological and molecular mechanisms to adapt to low nitrogen environment and promoting nitrogen transfer from senescent leaves to new leaves is crucial in improving Brassica's nitrogen use efficiency(NUE).Glutamine synthetase gene(GS)plays a vital role in helping plants reassimilate ammonium released from protein degradation in leaves,and it was the focus of our research on this topic.In this study,we identified high(H141)and low(L65)NUE genotypes of Brassica juncea with different responses to low-nitrogen stress.We found that H141 has a lower nitrate content but higher ammonium and free amino acid contents as well as higher nitrate reductase and GS activities in the shoots.These physiological indicators are responsible for the high NUE of H141.Wholegenome resequencing data revealed that 5,880 genes associated with NUE are polymorphic between H141 and L65.These genes participate in various amino acid,carbohydrate,and energy metabolic pathways.Haplotype analysis revealed two haplotypes for BjuB05.GS1.4,Hap1 and Hap2,which have multiple single nucleotide polymorphisms or insertions/deletions in the regulatory regions of the 5′and 3′untranslated regions and introns.Furthermore,the shoot NUE of Hap1 is significantly lower than that of Hap2.These two haplotypes of BjuB05.GS1.4 lead to differences in the shoot NUEs of different genetic populations of mustard and are associated with the local soil nitrogen content,suggesting that they might help mustard to adapt to different geographic localities.In conclusion,the results of our study shed light on the physiological and molecular mechanisms underlying different mustard NUE genotypes and demonstrate the enormous potential of NUE breeding in B.juncea.
基金supported by the National Natural Science Foundation of China(32172118)the National Key Research and Development Program of China(2016YFD0300110 and 2016YFD0300101)+1 种基金the Basic Scientific Research Fund of Chinese Academy of Agricultural Sciences,China(S2022ZD05)the Agricultural Science and Technology Innovation Program,China(CAAS-ZDRW202004)。
文摘The distributions of light and nitrogen within a plant's canopy reflect the growth adaptation of crops to the environment and are conducive to improving the carbon assimilation ability.So can the yield in crop production be maximized by improving the light and nitrogen distributions without adding any additional inputs?In this study,the effects of different nitrogen application rates and planting densities on the canopy light and nitrogen distributions of two highyielding maize cultivars(XY335 and DH618)and the regulatory effects of canopy physiological characteristics on radiation use efficiency(RUE)and yield were studied based on high-yield field experiments in Qitai,Xinjiang Uygur Autonomous Region,China,during 2019 and 2020.The results showed that the distribution of photosynthetically active photon flux density(PPFD)in the maize canopy decreased from top to bottom,while the vertical distribution of specific leaf nitrogen(SLN)initially increased and then decreased from top to bottom in the canopy.When SLN began to decrease,the PPDF values of XY335 and DH618 were 0.5 and 0.3,respectively,corresponding to 40.6 and49.3%of the total leaf area index(LAI).Nitrogen extinction coefficient(K_(N))/light extinction coefficient(K_(L))ratio in the middle and lower canopy of XY335(0.32)was 0.08 higher than that of DH618(0.24).The yield and RUE of XY335(17.2 t ha^(-1)and 1.8g MJ^(-1))were 7.0%(1.1 t ha^(-1))and 13.7%(0.2 g MJ^(-1))higher than those of DH618(16.1 t ha^(-1)and 1.6 g MJ^(-1)).Therefore,better light conditions(where the proportion of LAI in the upper and middle canopy was small)improved the light distribution when SLN started to decline,thus helping to mobilize the nitrogen distribution and maintain a high K_(N)and K_(N)/K_(L)ratio.In addition,K_(N)/K_(L)was a key parameter for yield improvement when the maize nutrient requirements were met at 360 kg N ha^(-1).At this level,an appropriately optimized high planting density could promote nitrogen utilization and produce higher yields and greater efficiency.The results of this study will be important for achieving high maize yields and the high efficiency cultivation and breeding of maize in the future.
基金supported by the Open Research Fund of Jiangxi Provincial Academy of Water Resources Sciences(2022SKTR05&2022SKTR03)the National Natural Science Foundation of China(42067049&42367049),the Jiangxi Provincial Natural Science Foundation(20242BAB25350)+5 种基金the Research Project of the Jiangxi Provincial Department of Forestry(CXZX(2025)14 and JXTG(2023)15)the Ganpo Juncai Plan(QN2023018)the Ganpo Yingcai Plan(gpyc20240038)the Double Thousand Plan of Jiangxi Province(jxsq2023102213 and jxsq2023102214)the Jiangxi Province“Science and Technology+Water Resources”Joint Plan Project(2023KSG01001)the Major Discipline Academic and Technical Leaders Training Program of Jiangxi Province(20243BCE51025).
文摘Stable carbon isotopes(δ^(13)C)are extensively utilized to study intrinsic water use efficiency(iWUE)at the leaf-scale in terrestrial ecosystems,serving as a crucial metric for assessing plant adaptation to climate change.However,there is currently a lack of consensus regarding the leaf-scale iWUE variation characteristics among different functional types.In this study,we measured theδ^(13)Cleaf and iWUE values of different functional plants(i.e.,life forms,leaf types,and mycorrhizal types)from 120 species across distinct habitat types(i.e.,hillside,nearpeak,and peak)in a subtropical forest on the western slope of Wuyi Mountains,southern China.The results showed that theδ^(13)Cleaf values of plants on the western slope of Wuyi Mountains ranged from-34.63‰to-30.04‰,and iWUE ranged from 5.93μmol mol^(-1)to 57.34μmol mol^(-1).Theδ^(13)Cleaf and iWUE values differed significantly among plant life forms,following the order of herbs>vine plants>shrubs>trees.Theδ^(13)Cleaf and iWUE values of ectomycorrhizal(ECM)species were greater than those of arbuscular mycorrhizal(AM)species despite there being no significant difference between plants with different leaf types(Simple leaves(SL)vs.Compound leaves(CL)).From the hillside to the peak,both at the community level and at the species level,theδ^(13)C values of leaves and iWUE values of plants exhibited an upward trend.The regression analysis revealed that leaf-scale iWUE was significantly negatively correlated with soil water content and significantly positively correlated with leaf phosphorus content.The findings indicated that leaf carbon isotope fractionation and corresponding iWUE can be influenced by life form,mycorrhizal type,and soil water availability.These insights provide a deeper understanding of the coupling mechanisms of carbon,water,and nutrients among different functional plant types in subtropical forests,and offer insights into predicting plant adaptability under climate change.
基金Under the auspices of the National Key Research and Development Program of China(No.2019YFA0606603)。
文摘Gross primary production(GPP)is a crucial indicator representing the absorption of atmospheric CO_(2) by vegetation.At present,the estimation of GPP by remote sensing is mainly based on leaf-related vegetation indexes and leaf-related biophysical para-meter leaf area index(LAI),which are not completely synchronized in seasonality with GPP.In this study,we proposed chlorophyll content-based light use efficiency model(CC-LUE)to improve GPP estimates,as chlorophyll is the direct site of photosynthesis,and only the light absorbed by chlorophyll is used in the photosynthetic process.The CC-LUE model is constructed by establishing a linear correlation between satellite-derived canopy chlorophyll content(Chlcanopy)and FPAR.This method was calibrated and validated utiliz-ing 7-d averaged in-situ GPP data from 14 eddy covariance flux towers covering deciduous broadleaf forest ecosystems across five dif-ferent climate zones.Results showed a relatively robust seasonal consistency between Chlcanopy with GPP in deciduous broadleaf forests under different climatic conditions.The CC-LUE model explained 88% of the in-situ GPP seasonality for all validation site-year and 56.0% of in-situ GPP variations through the growing season,outperforming the three widely used LUE models(MODIS-GPP algorithm,Vegetation Photosynthesis Model(VPM),and the eddy covariance-light use efficiency model(EC-LUE)).Additionally,the CC-LUE model(RMSE=0.50 g C/(m^(2)·d))significantly improved the underestimation of GPP during the growing season in semi-arid region,re-markably decreasing the root mean square error of averaged growing season GPP simulation and in-situ GPP by 75.4%,73.4%,and 37.5%,compared with MOD17(RMSE=2.03 g C/(m^(2)·d)),VPM(RMSE=1.88 g C/(m^(2)·d)),and EC-LUE(RMSE=0.80 g C/(m^(2)·d))model.The chlorophyll-based method proved superior in capturing the seasonal variations of GPP in forest ecosystems,thereby provid-ing the possibility of a more precise depiction of forest seasonal carbon uptake.
基金supported by the National Key Research and Development Program of China(2016YFD0600201)the National Nonprofit Institute Research Grant of CAF(CAFYBB2017ZB003)+1 种基金the National Natural Science Foundation of China(3187071631670720)。
文摘Understanding the relationship between forest management and water use efficiency(WUE)is important for evaluating forest adaptability to climate change.However,the effects of thinning and understory removal on WUE and its key controlling processes are not well understood,which limits our comprehension of the physiological mechanisms of various management practices.In this study,four forest management measures(no thinning:NT;understory removal:UR;light thinning:LT;and heavy thinning:HT)were carried out in Pinus massoniana plantations in a subtropical region of China.Photosynthetic capacity and needle stable carbon isotope composition(δ^(13)C)were measured to assess instantaneous water use efficiency(WUE_(inst))and long-term water use efficiency(WUE_(i)).Multiple regression models and structural equation modelling(SEM)identified the effects of soil properties and physiological performances on WUE_(inst)and WUE_(i).The results show that WUE_(inst)values among the four treatments were insignificant.However,compared with the NT stand(35.8μmol·mol^(-1)),WUE_(i)values significantly increased to 41.7μmol·mol^(-1)in the UR,50.1μmol·mol^(-1)in the LT and 46.6μmol·mol^(-1)in HT treatments,largely explained by photosynthetic capacity and soil water content.Understory removal did not change physiological performance(needle water potential and photosynthetic capacity).Thinning increased the net photosynthetic rate(A_n)but not stomatal conductance(g_s)or predawn needle water potential(ψ_(pd)),implying that the improvement in water use efficiency for thinned stands was largely driven by radiation interception than by soil water availability.In general,thinning may be an appropriate management measure to promote P.massoniana WUE to cope with seasonal droughts under future extreme climates.
基金supported by the Key R&D Plan of Hubei Province,China(2022BBA002)the Carbon Account Accounting and Carbon Reduction and Sequestration Technology Research of Quzhou City of China(2022-31).
文摘Controlled-release urea(CRU)is commonly used to improve the crop yield and nitrogen use efficiency(NUE).However,few studies have investigated the effects of CRU in the ratoon rice system.Ratoon rice is the practice of obtaining a second harvest from tillers originating from the stubble of the previously harvested main crop.In this study,a 2-year field experiment using a randomized complete block design was conducted to determine the effects of CRU on the yield,NUE,and economic benefits of ratoon rice,including the main crop,to provide a theoretical basis for fertilization of ratoon rice.The experiment included four treatments:(i)no N fertilizer(CK);(ii)traditional practice with 5 applications of urea applied at different crop growth stages by surface broadcasting(FFP);(iii)one-time basal application of CRU(BF1);and(iv)one-time basal application of CRU combined with common urea(BF2).The BF1 and BF2 treatments significantly increased the main crop yield by 17.47 and 15.99%in 2019,and by 17.91 and 16.44%in 2020,respectively,compared with FFP treatment.The BF2 treatment achieved similar yield of the ratoon crop to the FFP treatment,whereas the BF1 treatment significantly increased the yield of the ratoon crop by 14.81%in 2019 and 12.21%in 2020 compared with the FFP treatment.The BF1 and BF2 treatments significantly improved the 2-year apparent N recovery efficiency,agronomic NUE,and partial factor productivity of applied N by 11.47-16.66,27.31-44.49,and 9.23-15.60%,respectively,compared with FFP treatment.The BF1 and BF2 treatments reduced the chalky rice rate and chalkiness of main and ratoon crops relative to the FFP treatment.Furthermore,emergy analysis showed that the production efficiency of the BF treatments was higher than that of the FFP treatment.The BF treatments reduced labor input due to reduced fertilization times and improved the economic benefits of ratoon rice.Compared with the FFP treatment,the BF1 and BF2 treatments increased the net income by 14.21-16.87 and 23.76-25.96%,respectively.Overall,the one-time blending use of CRU and common urea should be encouraged to achieve high yield,high nitrogen use efficiency,and good quality of ratoon rice,which has low labor input and low apparent N loss.
基金funded by the National Natural Science Foundation of China(51969003)the Key Research and Development Project of Gansu Province(22YF7NA110)+4 种基金the Discipline Team Construction Project of Gansu Agricultural Universitythe Gansu Agricultural University Youth Mentor Support Fund Project(GAU-QDFC-2022-22)the Innovation Fund Project of Higher Education in Gansu Province(2022B-101)the Research Team Construction Project of College of Water Conservancy and Hydropower Engineering,Gansu Agricultural University(Gaucwky-01)the Gansu Water Science Experimental Research and Technology Extension Program(22GSLK023)。
文摘Wolfberry(Lycium barbarum L.)is important for health care and ecological protection.However,it faces problems of low productivity and resource utilization during planting.Exploring reasonable models for water and nitrogen management is important for solving these problems.Based on field trials in 2021 and 2022,this study analyzed the effects of controlling soil water and nitrogen application levels on wolfberry height,stem diameter,crown width,yield,and water(WUE)and nitrogen use efficiency(NUE).The upper and lower limits of soil water were controlled by the percentage of soil water content to field water capacity(θ_(f)),and four water levels,i.e.,adequate irrigation(W0,75%-85%θ_(f)),mild water deficit(W1,65%-75%θ_(f)),moderate water deficit(W2,55%-65%θ_(f)),and severe water deficit(W3,45%-55%θ_(f))were used,and three nitrogen application levels,i.e.,no nitrogen(N0,0 kg/hm^(2)),low nitrogen(N1,150 kg/hm^(2)),medium nitrogen(N2,300 kg/hm^(2)),and high nitrogen(N3,450 kg/hm^(2))were implied.The results showed that irrigation and nitrogen application significantly affected plant height,stem diameter,and crown width of wolfberry at different growth stages(P<0.01),and their maximum values were observed in W1N2,W0N2,and W1N3 treatments.Dry weight per plant and yield of wolfberry first increased and then decreased with increasing nitrogen application under the same water treatment.Dry weight per hundred grains and dry weight percentage increased with increasing nitrogen application under W0 treatment.However,under other water treatments,the values first increased and then decreased with increasing nitrogen application.Yield and its component of wolfberry first increased and then decreased as water deficit increased under the same nitrogen treatment.Irrigation water use efficiency(IWUE,8.46 kg/(hm^(2)·mm)),WUE(6.83 kg/(hm^(2)·mm)),partial factor productivity of nitrogen(PFPN,2.56 kg/kg),and NUE(14.29 kg/kg)reached their highest values in W2N2,W1N2,W1N2,and W1N1 treatments.Results of principal component analysis(PCA)showed that yield,WUE,and NUE were better in W1N2 treatment,making it a suitable water and nitrogen management mode for the irrigation area of the Yellow River in the Gansu Province,China and similar planting areas.
基金Under the auspices of the National Natural Science Foundation of China(No.42071219,42171198)。
文摘The effect of urban shrinkage has gradually become a new topic.Theoretically,urban shrinkage may exert great influence on land use efficiency(LUE)through various urban subsystems,but there is currently limited research examining these pathways.Using the Super-SBM-Undesirable model and the Structural Equation Model(SEM),this study calculates the LUE of shrinking cities in Northeast China and simulates the process of urban shrinkage affecting LUE.To quantify the process of urban shrinkage affecting LUE,three mediation variables,namely the economy,public services,and innovation,are used as latent variables to apply SEM.The results show that urban shrinkage will affect LUE through a direct path and indirect paths.In the direct path,urban shrinkage leads to an improvement in LUE.In the indirect paths,the economy and innovation will transmit the negative effect of urban shrinkage on LUE,while public services will reverse this effect.An important contribution of this study is that it quantifies the paths of urban shrinkage affecting LUE,thereby expanding the understanding of urban shrinkage effect and laying a foundation for the sustainable development of shrinking cities.
基金Natural Science Foundation of Heilongjiang,No.LH2023D019Philosophy and Social Sciences Research Program of Heilongjiang,No.21JLE323。
文摘The joint study of agriculture and rural areas is of great significance for safeguarding agricultural development,revitalizing rural areas,and enhancing farmers'well-being.This paper aims to assess the spatiotemporal evolution characteristics of the coupling and coordination degree of agricultural resilience and rural land use efficiency and their dynamic transfer law and driving mechanisms,based on panel data of 31 provinces(municipalities and autonomous regions)in China from 2010 to 2020.The results showed:(1)Good coupling and coordination of agricultural resilience and rural land use efficiency,with reduced temporal differentiation degrees between regions;(2)Significant spatial autocorrelation between the overall coupling and coordination degrees of agricultural resilience and rural land use efficiency,forming cold spot and hot spot spatial patterns in the western and eastern parts,respectively,with a central transition area;(3)A spillover effect of the dynamic transfer process,with a manifested specific law as"club convergence","Matthew effect",and progressive development characteristics;(4)The key roles of the natural,social,economic,and policy indicators in the coupling and coordination development process of agricultural resilience and rural land use efficiency.However,the selected indicators showed substantial spatial differences in their influences on the coupling and coordination process between provinces.
基金funded by the National Natural Science Foundation of China(31971843)the Modern Agroindustrial Technology System of Guangdong Province,China(2021KJ105)the Guangzhou Science and Technology Project,China(202103000075 and 202102100008)。
文摘Double-cropping rice in South China continues to break the total yield record,but the yield potential of singlecropping rice is not being realized.Radiation use efficiency(RUE)has been singled out as an important determinant of grain yield in many cereal species.However,there is no information on whether the yield gaps in doublecropping rice involve differences in RUE.Field experiments were performed over two years to evaluate the effects of intercepted radiation(IP)and RUE on the above-ground biomass production,crop growth rate(CGR),and harvest index(HI),in four representative rice varieties,i.e.,Xiangyaxiangzhan(XYXZ),Meixiangzhan 2(MXZ2),Nanjingxiangzhan(NJXZ),and Ruanhuayoujinsi(RHYJS),during the early and late seasons of rice cultivation in South China.The results revealed that grain yield in the early season was 8.2%higher than in the late season.The yield advantage in the early season was primarily due to higher spikelets per panicle and above-ground biomass resulting from a higher RUE.The spikelets per panicle in the early season were 6.5,8.3,6.9,and 8.5%higher in XYXZ,MXZ2,NJXZ,and RHYJS,respectively,than in the late season.The higher early season grain yield was more closely related to RUE in the middle tillering stage(R^(2)=0.34),panicle initiation(R^(2)=0.16),and maturation stage(R^(2)=0.28),and the intercepted photosynthetically active radiation(IPAR)in the maturation stage(R^(2)=0.28),while the late season grain yield was more dependent on IPAR in the middle tillering stage(R^(2)=0.31)and IPAR at panicle initiation(R^(2)=0.23).The results of this study conclusively show that higher RUE contributes to the yield progress of early season rice,while the yield improvement of late season rice is attributed to higher radiation during the early reproductive stage.Rationally allocating the RUE of double-cropping rice with high RUE varieties or adjustments of the sowing period merits further study.
基金Financial assistance project:Guangxi Forestry Science and Technology Project(Guilin kezi[2012]No.25).
文摘Camellia petelotii(Merr.)Sealy is an endangered Chinese native species that originates from Guangxi Zhuang Autonomous Region,China.Previous research demonstrated that proper water and fertilizer treatments could improve the growth and quality of Camellia species.This study uses a three-factor,five-level quadratic rotational combination experimental design to investigate the impact of water-fertilizer coupling on plant growth character-istics and the most suitable treatment for 24-month-old grafted C.petelotii seedlings.The experimental design includes irrigation levels[30%,40%,55%,70%,80%offield capacity(FC)],nitrogen application(0,2.17,5.43,8.70,10.87 g·plant^(-1)),and phosphorus application(0,0.96,2.40,3.85,4.81 g·plant^(-1)).The results indicated that:(1)Water-nitrogen and water-phosphorus interactions significantly affected ground diameter,chlorophyll content and specific leaf weight(SLW),while water-nitrogen interactions significantly affected plant height and photo-synthesis;(2)Application of nitrogen(8.70 g·plant^(-1))and phosphorus(3.85 g·plant^(-1))fertilizers under appropri-ate irrigation conditions(40%FC and 70%FC)improved growth.Applying fertilizers containing either nitrogen(10.87 g·plant^(-1))or phosphorus(4.81 g·plant^(-1))under adequate irrigation(55%FC)increased the Chl content.However,high nitrogen levels(10.87 g·plant^(-1))reduced photosynthesis.Conversely,it was enhanced under appropriate phosphorus(4.81 g·plant^(-1))when the irrigation level was 55%FC,indicating the sensitivity of C.pete-lotii seedlings to nitrogen fertilizer.(3)Under specific conditions of 40%FC or 70%FC irrigation and 8.70 g·plant^(-1) or 2.17 g·plant^(-1) nitrogen fertilizer application,3.85 g·plant^(-1) phosphorus addition boosted the SLW whereas,0.96 g·plant^(-1) phosphorus addition inhibited it.Under W=55%FC,deficiencies in either nitrogen(N=0 g·plant^(-1))or phosphorus(P=0 g·plant^(-1))significantly decreased leaf growth,affecting SLW.In summary,C.petelotii was more sensitive to nitrogen fertilizer at W=55%FC,and nitrogen deficiency inhibited C.petelotii growth in terms of ground diameter more than phosphorus deficiency.The C.petelotii seedlings performed best when treated with 55%FC,5.43 g·plant^(-1) nitrogen,2.40 g·plant^(-1) phosphorus per plant.These parameter esti-mates could optimize water and fertilizer application for C.petelotii seedlings.
文摘Whole_growing season pot experiments were conducted to examine the response of growth and water use efficiency ( WUE ) of spring wheat ( Triticum aestivum L. cv. Gaoyuan 602) to CO 2 enrichment. Wheat plants were grown in open_top chambers (OTCs) subject to two concentrations of CO 2 ()(350 and 700 μL/L, hereafter 'ambient' and 'elevated' respectively) and three soil water levels (80%, 60% and 40% field water capacity ( FWC ), hereafter 'high soil moisture', 'medium soil moisture' and 'low soil moisture' respectively). Elevated CO 2 greatly increased leaf net photosynthesis ( Pn ) at all three soil water levels. The Pn of plants growing under elevated was 22% lower than that of plants growing at ambient when measured with the same (700 μL/L). Plant growth was enhanced by elevated throughout the growing season, with an increase of 14.8% in shoot dry weight at harvest under high soil moisture, and leaf area was increased by about 20% at all three soil water levels. Elevated in combination with high soil moisture increased the ratio of plant shoot dry weight to height by 15.7%, while this ratio was decreased by over 50% when plants were subject to drought. Elevated also increased the water use efficiency of wheat, mainly due to decreases in transpiration and cumulative consumption of water, and an increase in shoot dry weight, with the biggest value of 30% occurring at high soil water moisture level. Compared to high soil moisture, drought decreased shoot dry weight by 72% under ambient , and by 76% under elevated . Similarly, drought also reduced WUE by 19% under ambient , and 23% under elevated . Our results indicate that: (1) elevated can increase the photosynthetic rates, growth and WUE of wheat plants; (2) long_term exposure to high may result in lower photosynthetic capacity; (3) high stimulates plants lateral growth more than vertical growth; (4) the effects of CO 2 enrichment on plants depend on soil water status, with plants benefiting more from CO 2 enrichment if sufficient water is supplied; and (5) drought may cause relatively more reduction in plant growth and WUE under future elevated conditions.
基金Supported by Special Fund for Agro-scientific Research in the Public Interest from Ministry of Agriculture(200903025-05)Fund from Kunming Municipal Science and Technology Committee(08S010201)~~
文摘[Objective] The aim of this study was to investigate the impacts of slow and controlled release fertilizers（SCRF）on the yield of qiubei hot pepper,its nutrient use efficiency and environment.[Method] Using Qiubei hot pepper（Capsicum frutescens L.）as the experimental material,we studied the fertilization effect and environment-protecting effect of SCRF.[Result] The result showed that SCRF could improve the agronomic characteristics of hot pepper.Compared to singly applied common fertilizers,SCRF increased economic yield by 20.90% and economic benefit by 13 234.35 Yuan/hm2,and the ratio of output to input was improved by 47.93%.In comparison with common straight fertilizers at same NPK proportion and rate,SCRF increased economic yield by 5.26% and economic benefit by 5 554.80 Yuan/hm2,and the ratio of output to input was improved by 9.91%.Under the reduced use of SCRF by 20%,SCRF increased economic yield by 12.38% and economic benefit by 9595.20 Yuan/hm2 compared with singly applied common fertilizers,and the ratio of output to input was improved by 65.95%.SCRF improved nitrogen,phosphorus and potassium use efficiencies by 12.42-17.53,3.35-5.24 and 5.37-14.02 percents respectively.[Conclusion] As the result of much reduced N and P application rates,SCRF would significantly economize fertilizer resources and minimize the pollution caused by the loss of fertilizer nutrients,which is of practical importance for environment protection.
文摘Major plant species in the Xilin River Basin were grouped into six plant functional groups (PFGs) based on their water ecological groups: xerophytes, mesoxerophytes, xeromesophytes, mesophytes, hygromesophytes and hygrophytes. We surveyed the composition, delta(13)C values and proline concentration of PFGs in eight different plant communities along a soil moisture gradient. Results show that: (1) PFGs occurred variously in eight steppe communities with different soil moisture status. In wetter habitats, hygromesophytes and hygrophytes were more abundant and accounted for the majority of aboveground biomass, whereas xerophytes and mesoxerophytes became more conspicuous in dryer habitats; (2) the numerical order of the mean delta(13)C values of PFGs is as follows: xerophytes (-26.38parts per thousand) = mesoxerophytes (-26.51parts per thousand) > xeromesophytes (-27.02parts per thousand) > mesophytes (-27.56parts per thousand) = hygromesophytes and hygrophytes (-27.80parts per thousand); (3) xerophytes maintained relative higher delta(13)C values and water use efficiency (WUE) in habitats of different water availability, whereas delta(13)C values of xeromesophytes were more sensitive to change in soil water availability; (4) From xerophytes to hygrophytes, their proline content markedly increased. Significantly positive correlations existed between proline and biomass or delta(13)C values of different water ecological groups.
文摘Photosynthesis ( P n ), transpiration ( E ) and water use efficiency ( WUE ) of more than 66 arid sand species from different environmental habitats, shifting sand dune, fixed sand dune, lowland and wetland in the Maowusu Sand Area were analyzed and the relation among these characteristics and the resource utilization efficiency, taxonomic categories and growth forms of the species were assessed. The results showed that species from Chenopodiaceae, Gramineae, Leguminosae which possessed the C 4 photosynthesis pathway, or C 3 pathway and also with nitrogen_fixation capacities had higher or the highest P n values, i.e., 20～30 μmol CO 2·m -2 ·s -1 , while that of evergreen shrub of Pinaceae had the lowest P n values, i.e., 0～5 μmol CO 2·m -2 ·s -1 . Those species from Compositae, Scrophulariaceae, and Gramineae with C 3 pathway but no N_fixation capacity had the highest E rates, i.e., 20～30 mmol H 2O·m -2 ·s -1 and again the evergreen shrub together with some species from Salicaceae and Compositae had the lowest E rates, i.e., 0～5 mmol H 2O·m -2 ·s -1 . Species from Leguminosae, Gramineae and Chenopodiaceae with C 4 pathway or C 3 pathway with N_fixation capacity, both shrubs and grasses, generally had higher WUE . However, even the physiological traits of the same species were habitat_ and season_specific. The values of both P n and E in late summer were much higher than those in early summer, with average increases of 26%, 40% respectively in the four habitats. WUE in late summer was, however, 12% lower. Generally, when the environments became drier as a result of habitats changed, i.e., in the order of wetland, lowland, fixed sand dune and shifting sand dune, P n and E decreased but WUE increased.
基金Supported by National Key Technology R&D Program(2006BAD05B06-04)Kunming Science and Technology Program(08S010201)~~
文摘[Objective] The aim was to study the effects of slow release fertilizer on the yield,economic benefit and nutrient use efficiency of carnation and environmental pollution.[Method] Taking carnation（Dianthus caryophyllus）as research object,the application effect and environmental protection effect of slow release fertilizer on carnation were discussed through field plot test.[Result] The main agronomic characters of carnation improved after the application of slow release fertilizer;compared with Conv-F treatment,the yield of carnation with slow release fertilizer increased by 18.67%-20.83%,and its economic benefit increased by 105 500 yuan/hm2,while the ratio of output to input improved by 74.29%;under the same NPK ratio and nutrient amount,the yield,economic benefit and ratio of output to input of carnation after the application of slow release fertilizer increased by 2.11%,14 800 yuan and 16.2%,respectively;besides,the application of slow release fertilizer improved the nutrient use efficiency of carnation,and N,P and K nutrient use efficiency in Opt-F-0.7% treatment increased by 13.88%,8.57% and 30.14% compared with Conv-F treatment.[Conclusion] Slow release fertilizer could not only reduce the waste of fertilizer resources and improve fertilizer use efficiency but also decrease the pollution caused by nutrient loss,which had important practical significance for protecting ecological environment and promoting the sustainable development of agriculture.
