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Effects of thinning and understory removal on water use efficiency of Pinus massoniana:evidence from photosynthetic capacity and stable carbon isotope analyses

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Journal of Forestry Research 2024年第2期35卷 42-53页

作者： Ting Wang Qing Xu Beibei Zhang Deqiang Gao Ying Zhang Jing Jiang Haijun Zuo Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration Ecology and Nature Conservation InstituteChinese Academy of ForestryBeijing 100091People’s Republic of China College of Agronomy and Agricultural Engineering Liaocheng UniversityLiaocheng 252000People’s Republic of China Department of Forest and Conservation Sciences Faculty of ForestryUniversity of British ColumbiaVancouverBC V6T 1Z4Canada

Understanding the relationship between forest management and water use efficiency(WUE)is important for evaluating forest adaptability to climate ***,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 *** 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 *** 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 ***,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 *** 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 *** general,thinning may be an appropriate management measure to promote *** WUE to cope with seasonal droughts under future extreme climates.

关键词： Stable carbon isotope water use efficiency Thinning Understory removal Photosynthetic capacity Needle water potential

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Stable carbon isotope composition and intrinsic water use efficiency in plants along an altitudinal gradient on the eastern slope of Yulong Snow Mountain, China

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Ecological Processes 2024年第2期13卷 218-230页

作者： Feng Jiang Tao Pu Zi-Jing Xue Yan-Wei Ma Xiao-Yi Shi Fu-Xi Shi College of Geography and Environmental Sciences Zhejiang Normal University Yulong Snow Mountain Glacier and Environment Observation and Research Station/State Key Laboratory of Cryospheric Sciences Northwest Institute of Eco-Environment and ResourcesChinese Academy of Sciences Key Laboratory of National Forestry and Grassland Administration on Forest Ecosystem Protection and Restoration of Poyang Lake watershed College of Forestry Jiangxi Agricultural University

Background Stable carbon isotope composition(δ13Cp) can be used to estimate the changes in intrinsic water use efficiency（iWUE） in plants,which helps us to better understand plants' response strategies to climate *** study focused on the variations in δ13Cpand iWUE for the different life-form plants（i.e.,herbs,shrubs,and trees）along an altitudinal gradient（3300,3600,3900,4100,4300,and 4500 m） on the eastern slope of Yulong Snow Mountain,southeastern margin of the Qinghai-Tibet *** response mechanisms of δ13Cpand iWUE for different life-form plants to altitude were thoroughly analyzed in this mountain *** The δ13Cpvalues of plants on the eastern slopes of Yulong Snow Mountain ranged from-30.4‰to-26.55‰,with a mean of-28.02‰,indicating a dominance of *** δ13Cpand iWUE values varied among different life-form plants in the order of herbs> shrubs> trees,particularly in 3600,3900,and 4300 ***δ13Cpand iWUE values for herbs and shrubs increased with altitude and were mainly controlled by air *** two parameters for trees exhibited a trend of initial decrease followed by an increase with *** 3900 m,the δ13Cpand iWUE values decreased with altitude,influenced by soil ***,above 3900 m,the two parameters increased with altitude,mainly regulated by air *** addition,iWUE was positively correlated with leaf P content but negatively correlated with leaf N:P ratio,especially for herbs and trees,suggesting that P plays a key role in modulating iWUE in this *** The diffe rentiated responses of water availability for different life-form plants to a higher altitudinal gradient are regulated by air temperature,soil moisture,and leaf P content in the Yulong Snow *** results provide valuable insights into understanding the wate r-carbon relationships in high-altitude ecosystems.

关键词： Stable carbon isotope water use efficiency Altitude Life form Yulong Snow Mountain

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water use efficiency and yield responses of cotton to field capacity-based deficit irrigation in an extremely arid area of China

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International Journal of Agricultural and Biological Engineering 2019年第6期12卷 91-101页

作者： Haifeng Li Zhiming Qi Dongwei Gui Fanjiang Zeng State Key Laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China School of Environmental and Land Resource Management Jiangxi Agricultural UniversityNanchang 330045China Cele National Station of Observation&Research for Desert-Grassland Ecosystem in Xinjiang Cele 848300XinjiangChina University of Chinese Academy of Sciences Beijing 100049China

The objectives of present investigation were to test the effects on water use efficiency(WUE)and cotton yield of implementing a range of deficit irrigation regimes triggered at specific fractions of root zone soil moisture,field capacity(θfc)and different crop phenological *** study was conducted on southern oasis of the Taklamakan desert,*** cotton crop’s WUE was quantified,as were leaf photosynthesis and *** a photosynthetic perspective,deficit irrigation resulted in 16.8%,10.3%and 2.2%increases in leaf WUE underθfc-based regulated deficit irrigation(T1,T2,and T3),compared to the control,*** yield and its components were significantly affected by irrigation depths(p≤0.05).A relatively high seed yield(0.65 kg/m3)and the highest WUE were achieved,under T3(70%θfc at seedling stage,60%θfc at squaring,50%θfc at full-bloom,70%θfc at boll,70%θfc at boll cracking stage),showing it to be the most effective and productive irrigation schedule *** the application ofθfc-based deficit irrigation in surface-irrigated cotton fields showed great potential in saving water,maintaining a high WUE,and improving cotton seed yield,a management strategy consisting or irrigation thresholds of 70%θfc in the root zone at the seedling,boll and boll cracking stages,and of 60%θfc at the squaring stage,and 50%θfc at the full-bloom stage,would be recommended for this extremely arid region.

关键词： regulated deficit irrigation evapotranspiration seed cotton yield water use efficiency Qira Oasis

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water use efficiency data from 2000 to 2019 in measuring progress towards SDGs in Central Asia

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Big Earth Data 2022年第1期6卷 90-102页

作者： Yaning Chen Gonghuan Fang Haichao Hao Xuanxuan Wang State Key Laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqiChina University of Chinese Academy of Sciences BeijingChina

Central Asia,located in the hinterland of the Eurasian continent,is characterized with sparse rainfall,frequent droughts and low water use *** water resources have become a key factor restricting the sustainable development of this *** assessing the efficiency of water resources utilization is the first step to achieve the UN Sustainable Development Goals(SDGs)in Central ***,since the collapse of the Soviet Union,the evalua-tion of water use efficiency is difficult due to low data availability and poor *** fill this gap,this paper developed a water use efficiency dataset(WUE)based on the Moderate Resolution Imaging Spectroradiometer(MODIS)Gross Primary Production(GPP)data and the MODIS evapotranspiration(ET)*** WUE dataset ranges from 2000 to 2019 with a spatial resolution of 500 *** agricultural WUE was then extracted based on the Global map of irrigated areas and MODIS land use *** a complementary,the water use amount per GDP was estimated for each *** present dataset could reflect changes in water use efficiency of agriculture and other sectors.

关键词： Central Asia water use efficiency MODIS agricultural water use

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Drought can offset potential water use efficiency of forest ecosystems from rising atmospheric CO2

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Journal of Environmental Sciences 2020年第4期32卷 262-274页

作者： Ning Liu Jatin Kala Shirong Liu Vanessa Haverd Bernard Dell Keith R.J.Smettem Richard J.Harper Environmental and Conservation Sciences Murdoch UniversityMurdochWA 6150 Australia Research Institute of Forest Ecology Environment and ProtectionChinese Academy of ForestryBeijing 10091 China CSIRO Oceans&Atmosphere ACT 2600 Australia

Increasing atmospheric CO2 is both leading to climate change and providing a potential fertilisation effect on plant ***,southern Australia has also experienced a significant decline in rainfall over the last 30 years,resulting in increased vegetative water *** better understand the dynamics and responses of Australian forest ecosystems to drought and elevated CO2,the magnitude and trend in water use efficiency(WUE)of forests,and their response to drought and elevated CO2 from 1982 to 2014 were analysed,using the best available model estimates constrained by observed fluxes from simulations with fixed and time-varying *** ratio of gross primary productivity(GPP)to evapotranspiration(ET)(WUEe)was used to identify the ecosystem scale WUE,while the ratio of GPP to transpiration(Tr)(WUEc)was used as a measure of canopy scale *** increased significantly in northern Australia(p<0.001)for woody savannas(WSA),whereas there was a slight decline in the WUE of evergreen broadleaf forests(EBF)in the southeast and southwest of *** lag of WUEc to drought was consistent and relatively short and stable between biomes(<3 months),but notably varied for WUEe,with a long time-lag(mean of 10 months).The dissimilar responses of WUEe and WUEc to climate change for different geographical areas result from the different proportion of Tr in ***2 fertilization and a wetter climate enhanced WUE in northern Australia,whereas drought offset the CO2 fertilization effect in southern Australia.

关键词： water use efficiency Elevated CO2 Carbon sequestration,drought Forest Australia

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Effect of smart sprinkler irrigation utilization on water use efficiency for wheat crops in arid regions

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International Journal of Agricultural and Biological Engineering 2014年第1期7卷 26-35页

作者： Hussein Mohammed Al-Ghobari Mohamed Said Abdalla El Marazky Department of Agricultural Engineering College of Food and Agriculture Sciences King Saud UniversityRiyadh 11451Kingdom of Saudi Arabia

The smart irrigation system(SIS)developed in this research is a valuable tool for scheduling irrigation and quantifying water required by *** was implemented and tested under sprinkler irrigation system to irrigate wheat crops(YecoraRojo).Results obtained from this system were compared with the control irrigation system(CIS),whose scheduling method was based on data from an automatic weather *** indicated significant savings in applied water using the *** addition,the use of the SIS conserved 12%of irrigation water compared to CIS and obtained an economical *** water use efficiency(WUE)under SIS had generally higher values(1.64 kg/m^(3))compared to CIS(1.46 kg/m^(3)).Hence,the application of SIS technology provides significant advantages on WUE and irrigation water use efficiency(IWUE).Relatively high WUE and IWUE were found for the irrigation treatment(80%of evapotranspiration under SIS).Results showed that the irrigation requirements of wheat increased(100%of ETc under CIS)with increasing evapotranspiration(ETc)but excessive irrigation could decrease WUE and *** results indicated that extreme irrigation might not produce higher yield or optimal economic benefit,thus,suitable irrigation schedules by using SIS must be established and extendable to other agricultural crops.

关键词： smart irrigation system(SIS) sprinkler irrigation scheduling water use efficiency arid region evapotranspiration grain yield

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Responses of global terrestrial water use efficiency to climate change and rising atmospheric CO_(2)concentration in the twenty-first century

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International Journal of Digital Earth 2018年第6期11卷 558-582页

作者： Shufen Pan Guangsheng Chen Wei Ren Shree R.S.Dangal Kamaljit Banger Jia Yang Bo Tao Hanqin Tian International Center for Climate and Global Change Research School of Forestry and Wildlife SciencesAuburn UniversityAuburnALUSA State Key Laboratory of Urban and Regional Ecology Research Center for EcoEnvironmental SciencesChinese Academy of SciencesBeijingPeople’s Republic of China Department of Plant and Soil Sciences College of AgricultureFood and EnvironmentUniversity of KentuckyLexingtonKYUSA

Terrestrial ecosystems play a significant role in global carbon and water cycles because of the substantial amount of carbon assimilated through net primary production and large amount of water loss through evapotranspiration(ET).Using a process-based ecosystem model,we investigate the potential effects of climate change and rising atmospheric CO_(2)concentration on global terrestrial ecosystem water use efficiency(WUE)during the twenty-first *** climate change would reduce global WUE by 16.3%under high-emission climate change scenario(A2)and 2.2%under low-emission climate scenario(B1)during 2010–***,the combination of rising atmospheric CO_(2)concentration and climate change would increase global WUE by 7.9%and 9.4%under A2 and B1 climate scenarios,*** suggests that rising atmospheric CO_(2)concentration could ameliorate climate change-induced WUE *** WUE would increase significantly at the high-latitude regions but decrease at the low-latitude regions under combined changes in climate and atmospheric CO_(2).The largest increase of WUE would occur in tundra and boreal needleleaf deciduous forest under the combined A2 climate and atmospheric CO_(2)*** accurate prediction of WUE requires deeper understanding on the responses of ET to rising atmospheric CO_(2)concentrations and its interactions with climate.

关键词： Climate change evapotranspiration net primary productivity water use efficiency

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Effects of grazing on net primary productivity,evapotranspiration and water use efficiency in the grasslands of Xinjiang,China

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Journal of Arid Land 2018年第4期10卷 588-600页

作者： HUANG Xiaotao LUO Geping YE Feipeng HAN Qifei State Key Laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China University of Chinese Academy of Sciences Beijing 100049China College of Resource and Environment Sciences Xinjiang UniversityUrumqi 830046China Nanjing University of Information Science&Technology Nanjing 210044China

Grazing is a main human activity in the grasslands of Xinjiang, China. It is vital to identify the effects of grazing on the sustainable utilization of local grasslands. However, the effects of grazing on net primary productivity （NPP）, evapotranspiration （ET） and water use efficiency （WUE） in this region remain unclear. Using the spatial Biome-BGC grazing model, we explored the effects of grazing on NPP, ET and WUE across the different regions and grassland types in Xinjiang during 1979-2012. NPP, ET and WUE under the grazed scenario were generally lower than those under the ungrazed scenario, and the differences showed increasing trends over time. The decreases in NPP, ET and WUE varied significantly among the regions and grassland types. NPP decreased as follows： among the regions, Northern Xinjiang （16.60 g C/（m2·a））, Tianshan Mountains （15.94 g C/（m2·a）） and Southern Xinjiang （-3.54 g C/（m2·a））; and among the grassland types, typical grasslands （25.70 g C/（m2·a））, swamp meadows （25.26 g C/（m2·a））, mid-mountain meadows （23.39 g C/（m2·a））, alpine meadows （6.33 g C/（m2·a））, desert grasslands （5.82 g C/（m2·a）） and saline meadows （2.90 g C/（me.a））. ET decreased as follows： among the regions, Tianshan Mountains （28.95 mm/a）, Northern Xinjiang （8.11 mm/a） and Southern Xinjiang （7.57 mm/a）; and among the grassland types, mid-mountain meadows （29.30 mm/a）, swamp meadows （25.07 mm·a）, typical grasslands （24.56 mm/a）, alpine meadows （20.69 mm/a）, desert grasslands （11.06 mm/a） and saline meadows （3.44 mm/a）. WUE decreased as follows： among the regions, Northern Xinjiang （0.053 g C/kg H2O）, Tianshan Mountains （0.034 g C/kg H2O） and Southern Xinjiang （0.012 g C/kg H2O）; and among the grassland types, typical grasslands （0.0609 g C/kg H2O）, swamp meadows （0.0548 g C/kg H2O）, mid-mountain meadows （0.0501 g C/kg H2O）, desert grasslands （0.0172 g C/kg H2O）, alpine meadows （0.0121 g C/kg H2O） and saline meadows （0.0067 g C/kg H2O）. In general, the decreases in NPP and WUE were m

关键词： grazing effect grassland type net primary productivity evapotranspiration water use efficiency BiomeBGC grazing model

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Controlled drainage in the Nile River delta of Egypt:a promising approach for decreasing drainage off-site effects and enhancing yield and water use efficiency of wheat

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Journal of Arid Land 2023年第4期15卷 460-476页

作者： Mohamed K EL-GHANNAM Fatma WASSAR Sabah MORSY Mohamed HAFEZ Chiter M PARIHAR Kent O BURKEY Ahmed M ABDALLAH Soil Water and Environment Research InstituteAgricultural Research CenterGiza 12112Egypt Higher Institute of water Sciences and Techniques of Gabès University of GabèsGabès 6072Tunisia Institute of Arid Regions Medenine 4119Tunisia Crop Science Department Faculty of AgricultureDamanhour UniversityDamanhour 22516Egypt Land and water Technologies Department Arid Lands Cultivation Research InstituteCity of Scientific Research and Technological ApplicationsNew Borg El-Arab 21934Egypt Indian Council of Agricultural Research(ICAR)-Indian Agricultural Research Institute(IARI) New Delhi 110012India United States Department of Agriculture(USDA)-Agricultural Research Services(ARS) Plant Science Research UnitNorth Carolina 27607USA Natural Resources and Agricultural Engineering Department Faculty of AgricultureDamanhour UniversityDamanhour 22516Egypt

North Africa is one of the most regions impacted by water *** implementation of controlled drainage(CD)in the northern Nile River delta of Egypt is one strategy to decrease irrigation,thus alleviating the negative impact of water *** study investigated the impacts of CD at different levels on drainage outflow,water table level,nitrate loss,grain yield,and water use efficiency(WUE)of various wheat *** levels of CD,i.e.,0.4 m below the soil surface(CD-0.4)and 0.8 m below the soil surface(CD-0.8),were compared with subsurface free drainage(SFD)at 1.2 m below the soil surface(SFD-1.2).Under each drainage treatment,four wheat cultivars were grown for two growing seasons(November 2018–April 2019 and November 2019–April 2020).Compared with SFD-1.2,CD-0.4 and CD-0.8 decreased irrigation water by 42.0%and 19.9%,drainage outflow by 40.3%and 27.3%,and nitrate loss by 35.3%and 20.8%,*** CD treatments,plants absorbed a significant portion of their evapotranspiration from shallow groundwater(22.0%and 8.0%for CD-0.4 and CD-0.8,respectively).All wheat cultivars positively responded to CD treatments,and the highest grain yield and straw yield were obtained under CD-0.4 *** the initial soil salinity as a reference,the soil salinity under CD-0.4 treatment increased two-fold by the end of the second growing season without negative impacts on wheat *** the drainage system by raising the outlet elevation and considering shallow groundwater contribution to crop evapotranspiration promoted water-saving and *** responses could be obtained based on the different plant tolerance to salinity and water stress,crop characteristics,and growth ***-specific soil salinity management practices will be required to avoid soil salinization due to the adoption of long-term shallow groundwater in Egypt and other similar agroecosystems.

关键词： drainage ratio nitrate loss water use efficiency yield soil salinity Nile River delta

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Improving water use efficiency by integrating fish culture and irrigation in coconut based farming system:A case study in Kasaragod District of Kerala(India)

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International Journal of Agricultural and Biological Engineering 2014年第2期7卷 36-44页

作者： Manoj P.Samuel A.C.Mathew National Academy of Agricultural Research Management Hyderabad-500030India Central Plantation Crops Research Institute KasaragodKerala-671124India

The crop production in the district of Kasaragod in Kerala State(India)is characterized by low input-low yield concept and rain-fed agriculture.A field study was conducted in Western Ghat region of the district to develop a suitable rainwater harvesting system adoptable to hilly terrains and to test its efficacy for improving the use efficiency of the harvested water by its multiple *** cost-benefit analysis of the water harvesting system was also carried out to find out its affordability to *** water harvesting system has been developed by integrating three components:(i)improving the productivity of coconut and component crops in the cropping units(ii)developing multiple water use systems,and(iii)the conjunctive use of the harvested water along with other surface and groundwater *** on the estimated annual costs and returns,the Benefit-Cost ratio was found to be 1.69 and all other financial viability criteria(IRR and NPV)were also found favourable for investment on a lined water harvesting tank integrated with a micro-irrigation system and fish *** study suggested that the rainwater harvesting could be implemented as a viable alternative to conventional water supply or on-farm irrigation projects considering the fact that any land anywhere can be used to harvest ***,the water use efficiency can be improved through effective harvesting and subsequent multiple uses of stored water.

关键词： rainwater harvesting water use efficiency plastic lined tank seepage loss fish culture financial viability

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