To comprehensively evaluate the alterations in water ecosystem service functions within arid watersheds,this study focused on the Bosten Lake Basin,which is situated in the arid region of Northwest China.The research ...To comprehensively evaluate the alterations in water ecosystem service functions within arid watersheds,this study focused on the Bosten Lake Basin,which is situated in the arid region of Northwest China.The research was based on land use/land cover(LULC),natural,socioeconomic,and accessibility data,utilizing the Patch-level Land Use Simulation(PLUS)and Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)models to dynamically assess LULC change and associated variations in water yield and water conservation.The analyses included the evaluation of contribution indices of various land use types and the investigation of driving factors that influence water yield and water conservation.The results showed that the change of LULC in the Bosten Lake Basin from 2000 to 2020 showed a trend of increasing in cultivated land and construction land,and decreasing in grassland,forest,and unused land.The unused land of all the three predicted scenarios of 2030(S1,a natural development scenario;S2,an ecological protection scenario;and S3,a cultivated land protection scenario)showed a decreasing trend.The scenarios S1 and S3 showed a trend of decreasing in grassland and increasing in cultivated land;while the scenario S2 showed a trend of decreasing in cultivated land and increasing in grassland.The water yield of the Bosten Lake Basin exhibited an initial decline followed by a slight increase from 2000 to 2020.The areas with higher water yield values were primarily located in the northern section of the basin,which is characterized by higher altitude.Water conservation demonstrated a pattern of initial decrease followed by stabilization,with the northeastern region demonstrating higher water conservation values.In the projected LULC scenarios of 2030,the estimated water yield under scenarios S1 and S3 was marginally greater than that under scenario S2;while the level of water conservation across all three scenarios remained rather consistent.The results showed that Hejing County is an important water conservation function zone,and the eastern part of the Xiaoyouledusi Basin is particularly important and should be protected.The findings of this study offer a scientific foundation for advancing sustainable development in arid watersheds and facilitating efficient water resource management.展开更多
Karst environmental issues have become one of the hot spots in contemporary international geological research. The same problem of water shortage is one of the hot spots of global concern. The peak-cluster depression ...Karst environmental issues have become one of the hot spots in contemporary international geological research. The same problem of water shortage is one of the hot spots of global concern. The peak-cluster depression basins in southwest of Guangxi is an important water connotation and ecological barrier areas in the Pearl River Basin of China. Thus, studying the spatial and temporal variations and the influencing factors of its water yield services is critical to achieve the sustainable development of water resources and ecological environmental protection in this region. As such, this paper uses the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST) model to assess the spatial and temporal variabilities of water yield services and its trends in the peak-cluster depression basins in southwest of Guangxi from 2000 to 2020. This work also integrates precipitation(Pre), reference evapotranspiration(ET), temperature(Tem), digital elevation model(DEM), slope, normalized difference vegetation index(NDVI), land use/land cover(LULC) and soil type to reveal the main factors that influence water yield services with the help of Geodetector. Results show that: 1) in time scale,the total annual water yield in the study area show a fluctuating and increasing trend from 2000 to 2020, with a growth rate of 7.3753 × 10^(8)m^(3)/yr, and its multi-year average water yield was 538.07 mm;2) in spatial pattern, with high yield areas mainly distributed in the south of the study area(mainly including Shangsi County, Pingxiang City, Ningming County, Longzhou County and Jingxi County), and low yield areas mainly distributed in Baise City and Nanning City;3) the dominant factor of water yield within karst and non-karst landforms is not necessarily controlled by precipitation, and the explanation degree of DEM factors in karst areas is significantly higher than that in non-karst areas;4) amongst the climatic factors, Pre, ET and Tem are dominant in the spatial pattern of region water yield capacity. among which Pre has the highest explanatory power for the spatial heterogeneity of annual water production, with q values above0.8, and each driver showed a significant interaction on the spatial distribution of water yield, with Pre exhibiting the strongest interaction with LULC.展开更多
With realizing the importance of ecosystem services to society, the efforts to evaluate the ecosystem services have increased. As the largest tributary of the Yellow River, the Weihe River has been endowed with many e...With realizing the importance of ecosystem services to society, the efforts to evaluate the ecosystem services have increased. As the largest tributary of the Yellow River, the Weihe River has been endowed with many ecological service functions. Among which, water yield can be a measure of local availability of water and an index for evaluating the conservation function of the region. This study aimed to explore the temporal and spatial variation of water yield and its influencing factors in the Weihe River Basin(WRB), and provide basis for formulating reasonable water resources utilization schemes. Based on the InVEST(integrated valuation of ecosystem services and tradeoffs) model, this study simulated the water yield in the WRB from 1985 to 2019, and discussed the impacts of climatic factors and land use change on water yield by spatial autocorrelation analysis and scenario analysis methods. The results showed that there was a slight increasing trend in water yield in the WRB over the study period with the increasing rate of 4.84 mm/10a and an average depth of 83.14 mm. The main water-producing areas were concentrated along the mainstream of the Weihe River and in the southern basin. Changes in water yield were comprehensively affected by climate and underlying surface factors. Precipitation was the main factor affecting water yield, which was consistent with water yield in time. And there existed significant spatial agglomeration between water yield and precipitation. Land use had little impact on the amount of water yield, but had an impact on its spatial distribution. Water yield was higher in areas with wide distribution of construction land and grassland. Water yield of different land use types were different. Unused land showed the largest water yield capacity, whereas grassland and farmland contributed most to the total water yield. The increasing water yield in the basin indicates an enhanced water supply service function of the ecosystem. These results are of great significance to the water resources management of the WRB.展开更多
A simplified water balance model in conjunc- tion with an evapotranspiration (ET) model and cumulative forest cover data were used to quantify the changes in annual water yield in response to reforestation in a larg...A simplified water balance model in conjunc- tion with an evapotranspiration (ET) model and cumulative forest cover data were used to quantify the changes in annual water yield in response to reforestation in a large watershed, northeast China. Cumulative forest cover increased by 22 %, leading to a significant decrease in estimated annual water yield. Reforestation increased ET (P = 0.0144), resulting in a remarkable decrease (P = 0.0001) in estimated annual water yield according to the water balance model. Reforestation increased ET by 33 mm and decreased annual water yield by 38 mm per decade. The effect of reforestation on annual water yield can be quantified using a simplified water balance model in a large watershed, although our reforestation area was small (about 20 %) in relation to the total watershed area.展开更多
Water resources are a basic need for social sustainable development and human existence.As an important national strategy for water resources security,spatial and temporal patterns and driving mechanisms of water yiel...Water resources are a basic need for social sustainable development and human existence.As an important national strategy for water resources security,spatial and temporal patterns and driving mechanisms of water yield ecosystem services on the Qingzang Plateau(QP)are critical for water resources management,optimal water allocation and the improvement of ecological water protection efficiency.However,only a few relevant studies are currently available.In this study,we simulated the water yield(WY)of the QP over 34 years,from 1982 to 2015,using the InVEST model and analyzed the spatiotemporal dynamic relationships between WY and climate change as well as between WY and vegetation change,using geographically weighted regression(GWR)models.The results showed that:1)from 1982 to 2015,the WY of the QP increased at an average rate of 3.8 mm/yr;2)WY presented a reduced spatial pattern from southeast to northwest;and 3)the WY driving factors have individual and spatial differences.In terms of the area percentage in promoting WY when analyzing each driving factor,precipitation(99.8%)and air pressure(53.3%)played the major roles in promoting WY,while temperature(71.9%),wind speed(57.2%),net primary productivity(87.2%),radiation(68.3%)and lake(87.7%)played negative roles.The areas where WY are dominated by temperature are the largest(41.1%),and followed by areas dominated by pressure(19.7%)and precipitation(18.5%).The results of this study provide scientific support for formulating regional water resources policy,social and economic development planning and other macro decisions for the QP.展开更多
This study develops a three-dimensional heterogeneous numerical model to simulate the water inrush process and predict the water yield for mineral exploration in Yangzhuang Iron Mine in Anhui Province. To identify the...This study develops a three-dimensional heterogeneous numerical model to simulate the water inrush process and predict the water yield for mineral exploration in Yangzhuang Iron Mine in Anhui Province. To identify the hydrogeological parameters of the aquifer in the study area, the model was calibrated and validated using the observed heads through the integrated trial-and-error and automated techniques. Also, the sensitivity analysis of the model was performed to evaluate the uncertainty associated with the calibrated model. According to the mine construction plan at different mining levels of-500 m,-600 m, and-700 m, the calibrated model was then applied to predict the water yields dependent on the different mining levels. As indicated by the prediction results, the numerical simulation model can systematically describe the groundwater system in the mining area and determine the source of water inrush in this iron mine. In conclusion, numerical analyses carried out in this study can provide guidance to decision-makers in balancing the iron ore mining and mine dewatering in the future.展开更多
The neutral network forecasting model based on the phase space reconstruction was proposed. First, through reconstructing the phase space, the time series of single variable was done excursion and expanded into multi-...The neutral network forecasting model based on the phase space reconstruction was proposed. First, through reconstructing the phase space, the time series of single variable was done excursion and expanded into multi- dimension series which included the ergodic information and more rich information could be excavated. Then, on the basis of the embedding dimension of the time series, the structure form of neutral network was constructed, of which the node number in input layer was the embedding dimension of the time series minus 1, and the node number in output layers was 1. Finally, as an example, the model was applied for water yield of mine forecasting. The result shows that the model has good fitting accuracy and forecasting precision.展开更多
This paper compares analytical and numerical methods by taking the forecasting of water yield of deep-buried iron mine in Yanzhou, Shandong as an example. Regarding the analytical method, the equation of infinite and ...This paper compares analytical and numerical methods by taking the forecasting of water yield of deep-buried iron mine in Yanzhou, Shandong as an example. Regarding the analytical method, the equation of infinite and bilateral water inflow boundary is used to forecast the water yield, and in the case of numerical simulation, we employed the GMS software to establish a model and further to forecast the water yield. On the one hand, through applying the analytical method, the maximum water yield of mine 1 500 m deep below the surface was calculated to be 13 645.17 m3/d; on the other hand, through adopting the numerical method, we obtained the predicted result of 3 816.16 m3/d. Meanwhile, by using the boundary generalization in the above-mentioned two methods, and through a comparative analysis of the actual hydro-geological conditions in this deep-buried mine, which also concerns the advantages and disadvantages of the two methods respectively, this paper draws the conclusion that the analytical method is only applicable in ideal conditions, but numerical method is eligible to be used in complex hydro-geological conditions. Therefore, it is more applicable to employ the numerical method to forecast water yield of deep-buried iron mine in Yanzhou, Shandong.展开更多
The hydrological system of a watershed is intricately influenced by both underlying characteristics and climate conditions.Understanding the variability in water yield is essential for effective water resources manage...The hydrological system of a watershed is intricately influenced by both underlying characteristics and climate conditions.Understanding the variability in water yield is essential for effective water resources management and water security in the context of changing environments.In this study,we adopted the Budyko framework and leveraged simulations from the CMIP6 model to investigate the compensation effects of climate and underlying characteristics on watershed water yield.Based on Taylor expansion and Budyko framework,we estimated the sensitivity of watershed water yield to climate and underlying characteristics(the first-and second-order partial derivatives).By combining external watershed characteristics(e.g.,water yield ratios and underlying characteristics)with internal sensitivity coefficients,this study further used vine copula and principal component analysis to quantify the stability of watershed water yield.Our findings show:(1)Water-yield changes related to underlying characteristics could be offset by climate-related water-yield changes across all climate zones,maintaining the water yield ratio steady(i.e.,the compensation effects).(2)However,global watersheds will turn more sensitive to underlying characteristics and less sensitive to climate variation in the future.Both climate-and underlying-related sensitivities increase in watersheds with arid climates.(3)The stability of watershed water yield will gradually diminish in the future.From 1901–1950to 2051–2100,the global stability of 280 watersheds drops from 0.054 to 0.021(i.e.,stability index identified by the joint probability).Particularly,the largest change in stability of water yield reaches-0.347±0.18 in arid regions.In semi-arid,semihumid,and humid regions,the changes are-0.039±0.010,-0.028±0.005,and-0.005±0.002,respectively.The findings provide a reference for the future sustainable water resources development under climate change,highlighting the vulnerability of the water resources in arid and semi-arid watersheds.展开更多
Water yield calculation and mapping are of great importance to water resource planning and management and hydropower station construction. A water yield model based on InVEST was employed to estimate water runoff in t...Water yield calculation and mapping are of great importance to water resource planning and management and hydropower station construction. A water yield model based on InVEST was employed to estimate water runoff in the Xitiaoxi River basin. The data included land use and land cover, average annual precipitation and potential evapotranspiration, soil depth, and plant available water content. In order to test model accuracy the natural runoff of Xitiaoxi River was estimated based on linear regression relation of rainfall-runoff in a ‘reference period’. After repeated validation, when the Z value was 6.5 the water yield was 8.30 E+8 m3 and this was a smaller difference with natural runoff. From the distribution of water yield, south and southwestern areas of the watershed had higher water yield volumes per hectare.展开更多
Natural ecosystems provide human society with very important products and services. With the rapid increase in population and the over-exploitation of natural resources, humans are continually enhancing the production...Natural ecosystems provide human society with very important products and services. With the rapid increase in population and the over-exploitation of natural resources, humans are continually enhancing the production of some services at the expense of others. This paper estimates changes in ecosystem services, and the relationship between these services in the Guanzhong-Tianshui Economic Region of China. These ecosystem changes are of great significance to the sustainable development of this economic region. The concept of production possibility frontier (PPF) is applied to evaluate the trade-offs and synergy between carbon sequestration, water yield and soil retention. Three land use strategy scenarios - planning, exploitation and protection - are applied to evaluate potential changes in ecosystem services. This study reveals noticeable trade-offs between carbon sequestration, soil retention and water yield, with synergy between carbon sequestration and soil retention. There are synergies between carbon sequestration, water yield and soil retention in the three scenarios. The protection scenario is the most favourable land use strategy for regulating ecosystem service capacity. This scenario results in the highest carbon sequestration, water yield and soil retention. The results could have implications for natural capital and ecosystem services planning, management and land use decision-making.展开更多
Guanting Reservoir(GR) is one of the most important water sources for Beijing and neighboring regions.Due to water pollution,it was withdrawn from the system to supply Beijing drinking water;however,after a thorough...Guanting Reservoir(GR) is one of the most important water sources for Beijing and neighboring regions.Due to water pollution,it was withdrawn from the system to supply Beijing drinking water;however,after a thorough treatment process,GR was made a reserve water source since 2007.To develop a comprehensive and quantitative analysis of water yield and purification services in the GR watershed,this study selected two time periods:the period when GR was withdrawn from the system supplying local drinking water and the period that it has been designated a reserve water source.The In VEST model was used to evaluate the quantities of water yields,and total nitrogen and total phosphorus outputs from 1995 to 2010 Additionally,the spatiotemporal variations of water yield services and water quality purification services in the GR watershed were analyzed.The results showed that water yield services in the GR watershed first weakened and then became stronger,but weakened overall during the years 1995 to 2010.Water yield capacity in the basin decreased from 1.89×10^9 m3 in 1995 to 1.43×10^9 m3 in 2010(a drop of 24.0% in total).Water quality purification services also showed the same tendency.Total nitrogen output decreased from 4028.7 t in 1995 to 3611.4 t in 2010,while total phosphorus decreased from 379.7 t in 1995 to 354.0 t in 2010.Nitrogen and phosphorus purification services were enhanced by 10.4% and 6.8%,respectively.Changes in the climate and land use were the main factors which lead to the changes in the water yield service in the GR watershed.Policies intended to protect water resource have matched the varying trends of water quality purification services during different periods.On one hand,the research results provide a foundation to identify key fields for eco-compensation in the Guanting Reservoir basin.On another hand,the ecosystem service value will increase on the basis of eco-compensation criteria through setting the scenarios of returning farmland to forest and ecological protection.This method directly reflects increases in ecosystem service values that have occurred since measures to protect the ecological environment have been implemented.This method is more persuasive and feasible than using eco-compensation criteria based on regional ecosystem service values determined by land use/coverage type.It can provide a new way to assess eco-compensation in the Guanting Reservoir basin and other regions.展开更多
Ecosystem services,which include water yield services,have been incorporated into decision processes of regional land use planning and sustainable development.Spatial pattern characteristics and identification of fact...Ecosystem services,which include water yield services,have been incorporated into decision processes of regional land use planning and sustainable development.Spatial pattern characteristics and identification of factors that influence water yield are the basis for decision making.However,there are limited studies on the driving mechanisms that affect the spatial heterogeneity of ecosystem services.In this study,we used the Hengduan Mountain region in southwest China,with obvious spatial heterogeneity,as the research site.The water yield module in the InVEST software was used to simulate the spatial distribution of water yield.Also,quantitative attribution analysis was conducted for various geomorphological and climatic zones in the Hengduan Mountain region by using the geographical detector method.Influencing factors,such as climate,topography,soil,vegetation type,and land use type and pattern,were taken into consideration for this analysis.Four key findings were obtained.First,water yield spatial heterogeneity is influenced most by climate-related factors,where precipitation and evapotranspiration are the dominant factors.Second,the relative importance of each impact factor to the water yield heterogeneity differs significantly by geomorphological and climatic zones.In flat areas,the influence of evapotranspiration is higher than that of precipitation.As relief increases,the importance of precipitation increases and eventually,it becomes the most influential factor.Evapotranspiration is the most influential factor in a plateau climate zone,while in the mid-subtropical zone,precipitation is the main controlling factor.Third,land use type is also an important driving force in flat areas.Thus,more attention should be paid to urbanization and land use planning,which involves land use changes,to mitigate the impact on water yield spatial pattern.The fourth finding was that a risk detector showed that Primarosol and Anthropogenic soil areas,shrub areas,and areas with slope<5°and 250-350 should be recognized as water yield important zones,while the corresponding elevation values are different among different geomorphological and climatic zones.Therefore,the spatial heterogeneity and influencing factors in different zones should be fully con-sidered while planning the maintenance and protection of water yield services in the Hengduan Mountain region.展开更多
Exploring the water yield and soil conservation in the Three-River-Source region is of great significance for evaluating both the ecological stability of the Qinghai-Tibet Plateau,Yellow River basin,Yangtze River basi...Exploring the water yield and soil conservation in the Three-River-Source region is of great significance for evaluating both the ecological stability of the Qinghai-Tibet Plateau,Yellow River basin,Yangtze River basin and Lancang River basin and the sustainable development of human society.The data sources for this study were land use/cover data from four phases(2000,2005,2010 and 2015),daily precipitation and temperature datasets,and the 1:1000000 Chinese soil database.These data were combined with vector data,such as data on settlements,roads,and rivers,along with population,economic raster datasets and CCSM4 common climate model prediction results.The Three-River-Source region was taken as the study area,and four land use/cover development scenarios and two climate change scenarios were designed based on the FLUS model and the downscaling correction method.The InVEST model was used to quantitatively simulate the water yield and soil erosion under different scenarios in the study area in 2030.The results showed the following:(1)Under different land use/cover development scenarios,grassland remained the dominant land use/cover type in the Three-River-Source region,and the area ratio was always greater than 67%.(2)Under the RCP4.5 climate scenario,the annual water yield and soil erosion increased by more than 7%and 3.9%,respectively.Under the RCP8.5 climate scenario,the annual water yield and soil erosion decreased by more than 3.3%and 1.3%,respectively.(3)Climate change played a leading role in the changes in water yield and soil erosion.Climate change contributed as much as 89.97%–98.00%to the change in water yield and 60.49%–95.64%to the change in the soil erosion modulus.However,the contribution of land use/cover changes to the change in regional water yield was only 2.00%–10.03%,and the contribution of the soil erosion modulus change was 4.36%–39.91%.Therefore,the land use development strategy in the Three-River-Source region should comprehensively consider issues such as regional development,the input of returning farmland to forest and grassland,and the resulting ecological benefits.展开更多
In order to further study the influence of high-yield-water on the productivity of CBM (coalbed methane) wells and the expulsion and production method carried out in CBM wells, by means of analyzing and researching ...In order to further study the influence of high-yield-water on the productivity of CBM (coalbed methane) wells and the expulsion and production method carried out in CBM wells, by means of analyzing and researching production characteris- tics and geologic condition of the CBM wells with high water yield in Yanchuannan block located at the eastern margin of Or- dos basin, the mechanism of high water yield decreasing the productivity of CBM well was discussed, and the expulsion and production method for this type of CBM well was proposed. The results show that high water yield would decrease the produc- tivity of CBM wells, and the mechanism is: first, in some circumstances, high water yield could reflect that there was dissipa- tion during the process of coalbed methane reservoir forming, which would lower the gas saturation of coal gas reservoir and reduce the productivity of CBM well; second, a large quantity of coalbed methane dissipated in the form of solution gas, caus- ing the practical reservoir pressure when gas appeared in casing to be lower than critical desorption pressure of the coal bed; finally, the CBM well with high water yield would have higher requirements of discharge and mining installation, system and continuity, and any link with problems would have a great impact on the well's productivity and would increase the difficulty of discharge and mining. In the case of wells with high water yield, the key is to select applicable discharge and mining installa- tion, which should be able to make the bottom hole flowing pressure decline smoothly and fast, and make the wells produce gas as quickly as possible but able to slow down the rate of discharge and mining properly when gas has appeared. In addition, in view of the CBM wells with high water yield, an installation lectotype method based on Darcy's law was proposed, which was found with good accuracy and practicability through field application.展开更多
Compared with conventional gas reservoir,percolation mechanism of coalbed methane(CBM)is completely different,it is remarkably affected by adsorption/desorption performance,pressure variation and coalbed characteristi...Compared with conventional gas reservoir,percolation mechanism of coalbed methane(CBM)is completely different,it is remarkably affected by adsorption/desorption performance,pressure variation and coalbed characteristics.Then it is difficult to calculate the controlled reserves of CBM wells.Moreover,the connection of edge-bottom water or interbedded water by fractures or faults may largely increase the water yield and drainage period,leading to obvious water invasion in some CBM wells.There are few literature about the predicted production for CBM wells with high water yield.Focusing on the unconventional CBM reservoir,methods of pseudo geological reserves and production index curves are adopted to establish the calculation model of water influx and controlled reserves.It further confirms that the calculation model is successfully applicated on the CBM wells at the middle part of Qinshui Basin in China.展开更多
The Ili River Delta(IRD)is an ecological security barrier for the Lake Balkhash and an important water conservation area in Central Asia.In this study,we selected the IRD as a typical research area,and simulated the w...The Ili River Delta(IRD)is an ecological security barrier for the Lake Balkhash and an important water conservation area in Central Asia.In this study,we selected the IRD as a typical research area,and simulated the water yield and water conservation from 1975 to 2020 using the water yield module of the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model.We further analyzed the temporal and spatial variations in the water yield and water conservation in the IRD from 1975 to 2020,and investigated the main driving factors(precipitation,potential evapotranspiration,land use/land cover change,and inflow from the Ili River)of the water conservation variation based on the linear regression,piecewise linear regression,and Pearson's correlation coefficient analyses.The results indicated that from 1975 to 2020,the water yield and water conservation in the IRD showed a decreasing trend,and the spatial distribution pattern was"high in the east and low in the west";overall,the water conservation of all land use types decreased slightly.The water conservation volume of grassland was the most reduced,although the area of grassland increased owing to the increased inflow from the Ili River.At the same time,the increased inflow has led to the expansion of wetland areas,the improvement of vegetation growth,and the increase of regional evapotranspiration,thus resulting in an overall reduction in the water conservation.The water conservation depth and precipitation had similar spatial distribution patterns;the change in climate factors was the main reason for the decline in the water conservation function in the delta.The reservoir in the upper reaches of the IRD regulated runoff into the Lake Balkhash,promoted vegetation restoration,and had a positive effect on the water conservation;however,this positive effect cannot offset the negative effect of enhanced evapotranspiration.These results provide a reference for the rational allocation of water resources and ecosystem protection in the IRD.展开更多
With increasing water shortage resources and extravagant nitrogen application, there is an urgent need to optimize irrigation regimes and nitrogen management for winter wheat(Triticum aestivum L.) in the North China...With increasing water shortage resources and extravagant nitrogen application, there is an urgent need to optimize irrigation regimes and nitrogen management for winter wheat(Triticum aestivum L.) in the North China Plain(NCP). A 4-year field experiment was conducted to evaluate the effect of three irrigation levels(W1, irrigation once at jointing stage; W2, irrigation once at jointing and once at heading stage; W3, irrigation once at jointing, once at heading, and once at filling stage; 60 mm each irrigation) and four N fertilizer rates(N0, 0; N1, 100 kg N ha-(-1); N2, 200 kg N ha-(-1); N3, 300 kg N ha-(-1)) on wheat yield, water use efficiency, fertilizer agronomic efficiency, and economic benefits. The results showed that wheat yield under W2 condition was similar to that under W3, and greater than that under W1 at the same nitrogen level. Yield with the N1 treatment was higher than that with the N0 treatment, but not significantly different from that obtained with the N2 and N3 treatments. The W2 N1 treatment resulted in the highest water use and fertilizer agronomic efficiencies. Compared with local traditional practice(W3 N3), the net income and output-input ratio of W2 N1 were greater by 12.3 and 19.5%, respectively. These findings suggest that two irrigation events of 60 mm each coupled with application of 100 kg N ha-(–1) is sufficient to provide a high wheat yield during drought growing seasons in the NCP.展开更多
Water shortage is a serious issue threatening the sustainable development of agriculture in the North China Plain, with the winter wheat (Triticum aestivum L.) as its largest water-consuming crop. The effects of til...Water shortage is a serious issue threatening the sustainable development of agriculture in the North China Plain, with the winter wheat (Triticum aestivum L.) as its largest water-consuming crop. The effects of tillage practices on the water consumption and water use efifciency (WUE) of wheat under high-yield conditions using supplemental irrigation based on testing soil moisture dynamic change were examined in this study. This experiment was conducted from 2007 to 2010, with ifve tillage practice treatments, namely, strip rotary tillage (SR), strip rotary tillage after subsoiling (SRS), rotary tillage (R), rotary tillage after subsoiling (RS), and plowing tillage (P). The results showed that in the SRS and RS treatments the total water and soil water consumptions were 11.81, 25.18%and 12.16, 14.75%higher than those in SR and R treatments, respectively. The lowest ratio of irrigation consumption to total water consumption in the SRS treatment was 18.53 and 21.88%for the 2008-2009 and 2009-2010 growing seasons, respectively. However, the highest percentage of water consumption was found in the SRS treatment from anthesis to maturity. No signiifcant difference was found between the WUE of the lfag leaf at the later iflling stage in the SRS and RS treatments, but the lfag leaf WUE at these stages were higher than those of other treatments. The SRS and RS treatments exhibited the highest grain yield (9 573.76 and 9 507.49 kg ha-1 for 3-yr average) with no signiifcant difference between the two treatments, followed by P, R and SR treatments. But the SRS treatment had the highest WUE. Thus, the 1-yr subsoiling tillage, plus 2 yr of strip rotary planting operation may be an efifcient measure to increase wheat yield and WUE.展开更多
基金This research was supported by the Special Project for the Construction of Innovation Environment in the Autonomous Region(2022D04007)the National Natural Science Foundation of China(42361030).
文摘To comprehensively evaluate the alterations in water ecosystem service functions within arid watersheds,this study focused on the Bosten Lake Basin,which is situated in the arid region of Northwest China.The research was based on land use/land cover(LULC),natural,socioeconomic,and accessibility data,utilizing the Patch-level Land Use Simulation(PLUS)and Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)models to dynamically assess LULC change and associated variations in water yield and water conservation.The analyses included the evaluation of contribution indices of various land use types and the investigation of driving factors that influence water yield and water conservation.The results showed that the change of LULC in the Bosten Lake Basin from 2000 to 2020 showed a trend of increasing in cultivated land and construction land,and decreasing in grassland,forest,and unused land.The unused land of all the three predicted scenarios of 2030(S1,a natural development scenario;S2,an ecological protection scenario;and S3,a cultivated land protection scenario)showed a decreasing trend.The scenarios S1 and S3 showed a trend of decreasing in grassland and increasing in cultivated land;while the scenario S2 showed a trend of decreasing in cultivated land and increasing in grassland.The water yield of the Bosten Lake Basin exhibited an initial decline followed by a slight increase from 2000 to 2020.The areas with higher water yield values were primarily located in the northern section of the basin,which is characterized by higher altitude.Water conservation demonstrated a pattern of initial decrease followed by stabilization,with the northeastern region demonstrating higher water conservation values.In the projected LULC scenarios of 2030,the estimated water yield under scenarios S1 and S3 was marginally greater than that under scenario S2;while the level of water conservation across all three scenarios remained rather consistent.The results showed that Hejing County is an important water conservation function zone,and the eastern part of the Xiaoyouledusi Basin is particularly important and should be protected.The findings of this study offer a scientific foundation for advancing sustainable development in arid watersheds and facilitating efficient water resource management.
基金Under the auspices of National Natural Science Foundation of China (No. 42061020)Natural Science Foundation of Guangxi Zhuang Autonomous Region (No. 2018JJA150135)+3 种基金Guangxi Key Research and Development Program (No. AA18118038)Science and Technology Department of Guangxi Zhuang Autonomous Region (No. 2019AC20088)The Program of Improving the Basic Research Ability of Young and Middle-aged Teachers in Guangxi Universities (No. 2021KY0431)High Level Talent Introduction Project of Beibu Gulf University (No. 2019KYQD28)。
文摘Karst environmental issues have become one of the hot spots in contemporary international geological research. The same problem of water shortage is one of the hot spots of global concern. The peak-cluster depression basins in southwest of Guangxi is an important water connotation and ecological barrier areas in the Pearl River Basin of China. Thus, studying the spatial and temporal variations and the influencing factors of its water yield services is critical to achieve the sustainable development of water resources and ecological environmental protection in this region. As such, this paper uses the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST) model to assess the spatial and temporal variabilities of water yield services and its trends in the peak-cluster depression basins in southwest of Guangxi from 2000 to 2020. This work also integrates precipitation(Pre), reference evapotranspiration(ET), temperature(Tem), digital elevation model(DEM), slope, normalized difference vegetation index(NDVI), land use/land cover(LULC) and soil type to reveal the main factors that influence water yield services with the help of Geodetector. Results show that: 1) in time scale,the total annual water yield in the study area show a fluctuating and increasing trend from 2000 to 2020, with a growth rate of 7.3753 × 10^(8)m^(3)/yr, and its multi-year average water yield was 538.07 mm;2) in spatial pattern, with high yield areas mainly distributed in the south of the study area(mainly including Shangsi County, Pingxiang City, Ningming County, Longzhou County and Jingxi County), and low yield areas mainly distributed in Baise City and Nanning City;3) the dominant factor of water yield within karst and non-karst landforms is not necessarily controlled by precipitation, and the explanation degree of DEM factors in karst areas is significantly higher than that in non-karst areas;4) amongst the climatic factors, Pre, ET and Tem are dominant in the spatial pattern of region water yield capacity. among which Pre has the highest explanatory power for the spatial heterogeneity of annual water production, with q values above0.8, and each driver showed a significant interaction on the spatial distribution of water yield, with Pre exhibiting the strongest interaction with LULC.
基金funded by the National Natural Science Foundation of China(U2243211)。
文摘With realizing the importance of ecosystem services to society, the efforts to evaluate the ecosystem services have increased. As the largest tributary of the Yellow River, the Weihe River has been endowed with many ecological service functions. Among which, water yield can be a measure of local availability of water and an index for evaluating the conservation function of the region. This study aimed to explore the temporal and spatial variation of water yield and its influencing factors in the Weihe River Basin(WRB), and provide basis for formulating reasonable water resources utilization schemes. Based on the InVEST(integrated valuation of ecosystem services and tradeoffs) model, this study simulated the water yield in the WRB from 1985 to 2019, and discussed the impacts of climatic factors and land use change on water yield by spatial autocorrelation analysis and scenario analysis methods. The results showed that there was a slight increasing trend in water yield in the WRB over the study period with the increasing rate of 4.84 mm/10a and an average depth of 83.14 mm. The main water-producing areas were concentrated along the mainstream of the Weihe River and in the southern basin. Changes in water yield were comprehensively affected by climate and underlying surface factors. Precipitation was the main factor affecting water yield, which was consistent with water yield in time. And there existed significant spatial agglomeration between water yield and precipitation. Land use had little impact on the amount of water yield, but had an impact on its spatial distribution. Water yield was higher in areas with wide distribution of construction land and grassland. Water yield of different land use types were different. Unused land showed the largest water yield capacity, whereas grassland and farmland contributed most to the total water yield. The increasing water yield in the basin indicates an enhanced water supply service function of the ecosystem. These results are of great significance to the water resources management of the WRB.
基金financially supported by the State Forestry Administration of China(201404201)the Guangxi Natural Science Foundation of China(2012GXNSFBA053140)+2 种基金the Fundamental Research Funds of Guangxi Academy of Sciences(13YJ22ZWS22)the Guangxi Institute of Botany(12001)CFERN&GENE Award Funds on Ecological Paper
文摘A simplified water balance model in conjunc- tion with an evapotranspiration (ET) model and cumulative forest cover data were used to quantify the changes in annual water yield in response to reforestation in a large watershed, northeast China. Cumulative forest cover increased by 22 %, leading to a significant decrease in estimated annual water yield. Reforestation increased ET (P = 0.0144), resulting in a remarkable decrease (P = 0.0001) in estimated annual water yield according to the water balance model. Reforestation increased ET by 33 mm and decreased annual water yield by 38 mm per decade. The effect of reforestation on annual water yield can be quantified using a simplified water balance model in a large watershed, although our reforestation area was small (about 20 %) in relation to the total watershed area.
基金supported by The Second Tibetan Plateau Scientific Expedition and Research(Grant No.2019QZKK0405)the Chinese Academy of Sciences through the Strategic Pilot Science and Technology Special Project(Category A)(Grant No.XDA2002040201)the Shaanxi Provincial Key Laboratory of Land Management Open Fund(Grant No.2018-ZD01).
文摘Water resources are a basic need for social sustainable development and human existence.As an important national strategy for water resources security,spatial and temporal patterns and driving mechanisms of water yield ecosystem services on the Qingzang Plateau(QP)are critical for water resources management,optimal water allocation and the improvement of ecological water protection efficiency.However,only a few relevant studies are currently available.In this study,we simulated the water yield(WY)of the QP over 34 years,from 1982 to 2015,using the InVEST model and analyzed the spatiotemporal dynamic relationships between WY and climate change as well as between WY and vegetation change,using geographically weighted regression(GWR)models.The results showed that:1)from 1982 to 2015,the WY of the QP increased at an average rate of 3.8 mm/yr;2)WY presented a reduced spatial pattern from southeast to northwest;and 3)the WY driving factors have individual and spatial differences.In terms of the area percentage in promoting WY when analyzing each driving factor,precipitation(99.8%)and air pressure(53.3%)played the major roles in promoting WY,while temperature(71.9%),wind speed(57.2%),net primary productivity(87.2%),radiation(68.3%)and lake(87.7%)played negative roles.The areas where WY are dominated by temperature are the largest(41.1%),and followed by areas dominated by pressure(19.7%)and precipitation(18.5%).The results of this study provide scientific support for formulating regional water resources policy,social and economic development planning and other macro decisions for the QP.
基金financially supported by the National Natural Science Foundation of China(No.41402198 and 41372235)Jiangsu Natural Science Fund-Youth Fund(No.BK20131009)the Fundamental Research Funds for the Central Universities(No.2014B03614)
文摘This study develops a three-dimensional heterogeneous numerical model to simulate the water inrush process and predict the water yield for mineral exploration in Yangzhuang Iron Mine in Anhui Province. To identify the hydrogeological parameters of the aquifer in the study area, the model was calibrated and validated using the observed heads through the integrated trial-and-error and automated techniques. Also, the sensitivity analysis of the model was performed to evaluate the uncertainty associated with the calibrated model. According to the mine construction plan at different mining levels of-500 m,-600 m, and-700 m, the calibrated model was then applied to predict the water yields dependent on the different mining levels. As indicated by the prediction results, the numerical simulation model can systematically describe the groundwater system in the mining area and determine the source of water inrush in this iron mine. In conclusion, numerical analyses carried out in this study can provide guidance to decision-makers in balancing the iron ore mining and mine dewatering in the future.
文摘The neutral network forecasting model based on the phase space reconstruction was proposed. First, through reconstructing the phase space, the time series of single variable was done excursion and expanded into multi- dimension series which included the ergodic information and more rich information could be excavated. Then, on the basis of the embedding dimension of the time series, the structure form of neutral network was constructed, of which the node number in input layer was the embedding dimension of the time series minus 1, and the node number in output layers was 1. Finally, as an example, the model was applied for water yield of mine forecasting. The result shows that the model has good fitting accuracy and forecasting precision.
文摘This paper compares analytical and numerical methods by taking the forecasting of water yield of deep-buried iron mine in Yanzhou, Shandong as an example. Regarding the analytical method, the equation of infinite and bilateral water inflow boundary is used to forecast the water yield, and in the case of numerical simulation, we employed the GMS software to establish a model and further to forecast the water yield. On the one hand, through applying the analytical method, the maximum water yield of mine 1 500 m deep below the surface was calculated to be 13 645.17 m3/d; on the other hand, through adopting the numerical method, we obtained the predicted result of 3 816.16 m3/d. Meanwhile, by using the boundary generalization in the above-mentioned two methods, and through a comparative analysis of the actual hydro-geological conditions in this deep-buried mine, which also concerns the advantages and disadvantages of the two methods respectively, this paper draws the conclusion that the analytical method is only applicable in ideal conditions, but numerical method is eligible to be used in complex hydro-geological conditions. Therefore, it is more applicable to employ the numerical method to forecast water yield of deep-buried iron mine in Yanzhou, Shandong.
基金supported by the National Natural Science Foundation of China(Grant No.52179031)the National Key Research and Development Program of China(Grant No.2021YFC3001000)+1 种基金the Outstanding Youth Fund of Guangdong Province(Grant No.2023B1515020116)the Team Project of Pearl River Talent Program(Grant No.2019ZT08G090)。
文摘The hydrological system of a watershed is intricately influenced by both underlying characteristics and climate conditions.Understanding the variability in water yield is essential for effective water resources management and water security in the context of changing environments.In this study,we adopted the Budyko framework and leveraged simulations from the CMIP6 model to investigate the compensation effects of climate and underlying characteristics on watershed water yield.Based on Taylor expansion and Budyko framework,we estimated the sensitivity of watershed water yield to climate and underlying characteristics(the first-and second-order partial derivatives).By combining external watershed characteristics(e.g.,water yield ratios and underlying characteristics)with internal sensitivity coefficients,this study further used vine copula and principal component analysis to quantify the stability of watershed water yield.Our findings show:(1)Water-yield changes related to underlying characteristics could be offset by climate-related water-yield changes across all climate zones,maintaining the water yield ratio steady(i.e.,the compensation effects).(2)However,global watersheds will turn more sensitive to underlying characteristics and less sensitive to climate variation in the future.Both climate-and underlying-related sensitivities increase in watersheds with arid climates.(3)The stability of watershed water yield will gradually diminish in the future.From 1901–1950to 2051–2100,the global stability of 280 watersheds drops from 0.054 to 0.021(i.e.,stability index identified by the joint probability).Particularly,the largest change in stability of water yield reaches-0.347±0.18 in arid regions.In semi-arid,semihumid,and humid regions,the changes are-0.039±0.010,-0.028±0.005,and-0.005±0.002,respectively.The findings provide a reference for the future sustainable water resources development under climate change,highlighting the vulnerability of the water resources in arid and semi-arid watersheds.
基金National Major Water Pollution Control Project(No.2008ZX07526-007)
文摘Water yield calculation and mapping are of great importance to water resource planning and management and hydropower station construction. A water yield model based on InVEST was employed to estimate water runoff in the Xitiaoxi River basin. The data included land use and land cover, average annual precipitation and potential evapotranspiration, soil depth, and plant available water content. In order to test model accuracy the natural runoff of Xitiaoxi River was estimated based on linear regression relation of rainfall-runoff in a ‘reference period’. After repeated validation, when the Z value was 6.5 the water yield was 8.30 E+8 m3 and this was a smaller difference with natural runoff. From the distribution of water yield, south and southwestern areas of the watershed had higher water yield volumes per hectare.
基金National Natural Science Foundation of China, No.41371020 Fundamental Research Funds for the Central Universities, No.GK201502010+2 种基金 Innovation Funds of Graduate Programs, Shaanxi Normal University, No.2015CXS045 China Postdoctoral Science Foundation on the 58th Group, No.2015M582706 The Postdoctoral Scientific Research Project Foundation of Shaanxi Province in 2015
文摘Natural ecosystems provide human society with very important products and services. With the rapid increase in population and the over-exploitation of natural resources, humans are continually enhancing the production of some services at the expense of others. This paper estimates changes in ecosystem services, and the relationship between these services in the Guanzhong-Tianshui Economic Region of China. These ecosystem changes are of great significance to the sustainable development of this economic region. The concept of production possibility frontier (PPF) is applied to evaluate the trade-offs and synergy between carbon sequestration, water yield and soil retention. Three land use strategy scenarios - planning, exploitation and protection - are applied to evaluate potential changes in ecosystem services. This study reveals noticeable trade-offs between carbon sequestration, soil retention and water yield, with synergy between carbon sequestration and soil retention. There are synergies between carbon sequestration, water yield and soil retention in the three scenarios. The protection scenario is the most favourable land use strategy for regulating ecosystem service capacity. This scenario results in the highest carbon sequestration, water yield and soil retention. The results could have implications for natural capital and ecosystem services planning, management and land use decision-making.
基金National Natural Science Foundation of China(51379084)National Key R&D Plan(2016YFC0503405)
文摘Guanting Reservoir(GR) is one of the most important water sources for Beijing and neighboring regions.Due to water pollution,it was withdrawn from the system to supply Beijing drinking water;however,after a thorough treatment process,GR was made a reserve water source since 2007.To develop a comprehensive and quantitative analysis of water yield and purification services in the GR watershed,this study selected two time periods:the period when GR was withdrawn from the system supplying local drinking water and the period that it has been designated a reserve water source.The In VEST model was used to evaluate the quantities of water yields,and total nitrogen and total phosphorus outputs from 1995 to 2010 Additionally,the spatiotemporal variations of water yield services and water quality purification services in the GR watershed were analyzed.The results showed that water yield services in the GR watershed first weakened and then became stronger,but weakened overall during the years 1995 to 2010.Water yield capacity in the basin decreased from 1.89×10^9 m3 in 1995 to 1.43×10^9 m3 in 2010(a drop of 24.0% in total).Water quality purification services also showed the same tendency.Total nitrogen output decreased from 4028.7 t in 1995 to 3611.4 t in 2010,while total phosphorus decreased from 379.7 t in 1995 to 354.0 t in 2010.Nitrogen and phosphorus purification services were enhanced by 10.4% and 6.8%,respectively.Changes in the climate and land use were the main factors which lead to the changes in the water yield service in the GR watershed.Policies intended to protect water resource have matched the varying trends of water quality purification services during different periods.On one hand,the research results provide a foundation to identify key fields for eco-compensation in the Guanting Reservoir basin.On another hand,the ecosystem service value will increase on the basis of eco-compensation criteria through setting the scenarios of returning farmland to forest and ecological protection.This method directly reflects increases in ecosystem service values that have occurred since measures to protect the ecological environment have been implemented.This method is more persuasive and feasible than using eco-compensation criteria based on regional ecosystem service values determined by land use/coverage type.It can provide a new way to assess eco-compensation in the Guanting Reservoir basin and other regions.
基金National Basic Research Program of China,No.2015CB452702National Natural Science Foundation of China,No.41571098.No.41530749+1 种基金National Key R&D Program of China,No.2017YFC1502903Major Consulting Project of Strategic Development Institute,Chinese Academy of Sciences,No.Y02015001。
文摘Ecosystem services,which include water yield services,have been incorporated into decision processes of regional land use planning and sustainable development.Spatial pattern characteristics and identification of factors that influence water yield are the basis for decision making.However,there are limited studies on the driving mechanisms that affect the spatial heterogeneity of ecosystem services.In this study,we used the Hengduan Mountain region in southwest China,with obvious spatial heterogeneity,as the research site.The water yield module in the InVEST software was used to simulate the spatial distribution of water yield.Also,quantitative attribution analysis was conducted for various geomorphological and climatic zones in the Hengduan Mountain region by using the geographical detector method.Influencing factors,such as climate,topography,soil,vegetation type,and land use type and pattern,were taken into consideration for this analysis.Four key findings were obtained.First,water yield spatial heterogeneity is influenced most by climate-related factors,where precipitation and evapotranspiration are the dominant factors.Second,the relative importance of each impact factor to the water yield heterogeneity differs significantly by geomorphological and climatic zones.In flat areas,the influence of evapotranspiration is higher than that of precipitation.As relief increases,the importance of precipitation increases and eventually,it becomes the most influential factor.Evapotranspiration is the most influential factor in a plateau climate zone,while in the mid-subtropical zone,precipitation is the main controlling factor.Third,land use type is also an important driving force in flat areas.Thus,more attention should be paid to urbanization and land use planning,which involves land use changes,to mitigate the impact on water yield spatial pattern.The fourth finding was that a risk detector showed that Primarosol and Anthropogenic soil areas,shrub areas,and areas with slope<5°and 250-350 should be recognized as water yield important zones,while the corresponding elevation values are different among different geomorphological and climatic zones.Therefore,the spatial heterogeneity and influencing factors in different zones should be fully con-sidered while planning the maintenance and protection of water yield services in the Hengduan Mountain region.
基金The National Key Research and Development Program of China(2016YFC0503701,2016YFB0501502)The Strategic Priority Research Program of Chinese Academy of Sciences(XDA19040301,XDA20010202,XDA23100201)The Key Project of the High Resolution Earth Observation System in China(00-Y30B14-9001-14/16)
文摘Exploring the water yield and soil conservation in the Three-River-Source region is of great significance for evaluating both the ecological stability of the Qinghai-Tibet Plateau,Yellow River basin,Yangtze River basin and Lancang River basin and the sustainable development of human society.The data sources for this study were land use/cover data from four phases(2000,2005,2010 and 2015),daily precipitation and temperature datasets,and the 1:1000000 Chinese soil database.These data were combined with vector data,such as data on settlements,roads,and rivers,along with population,economic raster datasets and CCSM4 common climate model prediction results.The Three-River-Source region was taken as the study area,and four land use/cover development scenarios and two climate change scenarios were designed based on the FLUS model and the downscaling correction method.The InVEST model was used to quantitatively simulate the water yield and soil erosion under different scenarios in the study area in 2030.The results showed the following:(1)Under different land use/cover development scenarios,grassland remained the dominant land use/cover type in the Three-River-Source region,and the area ratio was always greater than 67%.(2)Under the RCP4.5 climate scenario,the annual water yield and soil erosion increased by more than 7%and 3.9%,respectively.Under the RCP8.5 climate scenario,the annual water yield and soil erosion decreased by more than 3.3%and 1.3%,respectively.(3)Climate change played a leading role in the changes in water yield and soil erosion.Climate change contributed as much as 89.97%–98.00%to the change in water yield and 60.49%–95.64%to the change in the soil erosion modulus.However,the contribution of land use/cover changes to the change in regional water yield was only 2.00%–10.03%,and the contribution of the soil erosion modulus change was 4.36%–39.91%.Therefore,the land use development strategy in the Three-River-Source region should comprehensively consider issues such as regional development,the input of returning farmland to forest and grassland,and the resulting ecological benefits.
文摘In order to further study the influence of high-yield-water on the productivity of CBM (coalbed methane) wells and the expulsion and production method carried out in CBM wells, by means of analyzing and researching production characteris- tics and geologic condition of the CBM wells with high water yield in Yanchuannan block located at the eastern margin of Or- dos basin, the mechanism of high water yield decreasing the productivity of CBM well was discussed, and the expulsion and production method for this type of CBM well was proposed. The results show that high water yield would decrease the produc- tivity of CBM wells, and the mechanism is: first, in some circumstances, high water yield could reflect that there was dissipa- tion during the process of coalbed methane reservoir forming, which would lower the gas saturation of coal gas reservoir and reduce the productivity of CBM well; second, a large quantity of coalbed methane dissipated in the form of solution gas, caus- ing the practical reservoir pressure when gas appeared in casing to be lower than critical desorption pressure of the coal bed; finally, the CBM well with high water yield would have higher requirements of discharge and mining installation, system and continuity, and any link with problems would have a great impact on the well's productivity and would increase the difficulty of discharge and mining. In the case of wells with high water yield, the key is to select applicable discharge and mining installa- tion, which should be able to make the bottom hole flowing pressure decline smoothly and fast, and make the wells produce gas as quickly as possible but able to slow down the rate of discharge and mining properly when gas has appeared. In addition, in view of the CBM wells with high water yield, an installation lectotype method based on Darcy's law was proposed, which was found with good accuracy and practicability through field application.
基金The work was supported by the Natural Science Foundation of China(No.U1762212 and 51374181)the State Key Laboratory of CBM Enrichment Mechanisms(No.2016SZ05036-002).
文摘Compared with conventional gas reservoir,percolation mechanism of coalbed methane(CBM)is completely different,it is remarkably affected by adsorption/desorption performance,pressure variation and coalbed characteristics.Then it is difficult to calculate the controlled reserves of CBM wells.Moreover,the connection of edge-bottom water or interbedded water by fractures or faults may largely increase the water yield and drainage period,leading to obvious water invasion in some CBM wells.There are few literature about the predicted production for CBM wells with high water yield.Focusing on the unconventional CBM reservoir,methods of pseudo geological reserves and production index curves are adopted to establish the calculation model of water influx and controlled reserves.It further confirms that the calculation model is successfully applicated on the CBM wells at the middle part of Qinshui Basin in China.
基金funded by the National Natural Science Foundation of China(42071245)the Xinjiang Uygur Autonomous Region Innovation Environment Construction Special Project&Science and Technology Innovation Base Construction Project(PT2107)+2 种基金the Third Xinjiang Comprehensive Scientific Survey Project Sub-topic(2021xjkk140305)the Tianshan Talent Training Program of Xinjiang Uygur Autonomous Region(2022TSYCLJ0011)the K.C.Wong Education Foundation(GJTD-2020-14).
文摘The Ili River Delta(IRD)is an ecological security barrier for the Lake Balkhash and an important water conservation area in Central Asia.In this study,we selected the IRD as a typical research area,and simulated the water yield and water conservation from 1975 to 2020 using the water yield module of the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model.We further analyzed the temporal and spatial variations in the water yield and water conservation in the IRD from 1975 to 2020,and investigated the main driving factors(precipitation,potential evapotranspiration,land use/land cover change,and inflow from the Ili River)of the water conservation variation based on the linear regression,piecewise linear regression,and Pearson's correlation coefficient analyses.The results indicated that from 1975 to 2020,the water yield and water conservation in the IRD showed a decreasing trend,and the spatial distribution pattern was"high in the east and low in the west";overall,the water conservation of all land use types decreased slightly.The water conservation volume of grassland was the most reduced,although the area of grassland increased owing to the increased inflow from the Ili River.At the same time,the increased inflow has led to the expansion of wetland areas,the improvement of vegetation growth,and the increase of regional evapotranspiration,thus resulting in an overall reduction in the water conservation.The water conservation depth and precipitation had similar spatial distribution patterns;the change in climate factors was the main reason for the decline in the water conservation function in the delta.The reservoir in the upper reaches of the IRD regulated runoff into the Lake Balkhash,promoted vegetation restoration,and had a positive effect on the water conservation;however,this positive effect cannot offset the negative effect of enhanced evapotranspiration.These results provide a reference for the rational allocation of water resources and ecosystem protection in the IRD.
基金supported by the National Key Research and Development Program of China (2016YFD0300808)the National Key Technologies R&D Program of China during the 12th Five-Year Plan period (2013BAD05B02)+2 种基金the National Natural Science Foundation of China (31571612 and 31100191)the Science and Technology Service Network Initiative of Chinese Academy of Sciences (KFJ-STSZDTP-001)the Hebei Key Research and Development Program, China (15226407D and 17227006D)
文摘With increasing water shortage resources and extravagant nitrogen application, there is an urgent need to optimize irrigation regimes and nitrogen management for winter wheat(Triticum aestivum L.) in the North China Plain(NCP). A 4-year field experiment was conducted to evaluate the effect of three irrigation levels(W1, irrigation once at jointing stage; W2, irrigation once at jointing and once at heading stage; W3, irrigation once at jointing, once at heading, and once at filling stage; 60 mm each irrigation) and four N fertilizer rates(N0, 0; N1, 100 kg N ha-(-1); N2, 200 kg N ha-(-1); N3, 300 kg N ha-(-1)) on wheat yield, water use efficiency, fertilizer agronomic efficiency, and economic benefits. The results showed that wheat yield under W2 condition was similar to that under W3, and greater than that under W1 at the same nitrogen level. Yield with the N1 treatment was higher than that with the N0 treatment, but not significantly different from that obtained with the N2 and N3 treatments. The W2 N1 treatment resulted in the highest water use and fertilizer agronomic efficiencies. Compared with local traditional practice(W3 N3), the net income and output-input ratio of W2 N1 were greater by 12.3 and 19.5%, respectively. These findings suggest that two irrigation events of 60 mm each coupled with application of 100 kg N ha-(–1) is sufficient to provide a high wheat yield during drought growing seasons in the NCP.
基金the supports from the National Natural Science Foundation of China (31171498 and 31401334)the Project of Technology System in Modern Wheat Industry, Ministry of Agriculture, China (CARS-3-1-19)
文摘Water shortage is a serious issue threatening the sustainable development of agriculture in the North China Plain, with the winter wheat (Triticum aestivum L.) as its largest water-consuming crop. The effects of tillage practices on the water consumption and water use efifciency (WUE) of wheat under high-yield conditions using supplemental irrigation based on testing soil moisture dynamic change were examined in this study. This experiment was conducted from 2007 to 2010, with ifve tillage practice treatments, namely, strip rotary tillage (SR), strip rotary tillage after subsoiling (SRS), rotary tillage (R), rotary tillage after subsoiling (RS), and plowing tillage (P). The results showed that in the SRS and RS treatments the total water and soil water consumptions were 11.81, 25.18%and 12.16, 14.75%higher than those in SR and R treatments, respectively. The lowest ratio of irrigation consumption to total water consumption in the SRS treatment was 18.53 and 21.88%for the 2008-2009 and 2009-2010 growing seasons, respectively. However, the highest percentage of water consumption was found in the SRS treatment from anthesis to maturity. No signiifcant difference was found between the WUE of the lfag leaf at the later iflling stage in the SRS and RS treatments, but the lfag leaf WUE at these stages were higher than those of other treatments. The SRS and RS treatments exhibited the highest grain yield (9 573.76 and 9 507.49 kg ha-1 for 3-yr average) with no signiifcant difference between the two treatments, followed by P, R and SR treatments. But the SRS treatment had the highest WUE. Thus, the 1-yr subsoiling tillage, plus 2 yr of strip rotary planting operation may be an efifcient measure to increase wheat yield and WUE.