Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract： The arid region of Northwest China is one of the driest regions in the world and is characterized with severe water scarcity.Water shortage is the most critical natural factor limiting the high-quality economic and social development and ecological security in the arid region of Northwest China. Based on the long-term monitoring data from the field stations of Chinese Academy of Sciences, observation data of meteorological stations, water resources bulletin and the remote sensing data, this study systematically analyzes the basic characteristics of water resources and ecological environment in the arid region of Northwest China, assesses the changing trends of hydrological elements, water resources, and ecological environment. Besides, this study analyzes the changes of water resources carrying capacity in terms of water use structure and water resources utilization efficiency, and puts forward some suggestions on sustainable water resources utilization and ecological and environmental protection. The results show that the temperature in the arid region of Northwest China has increased at a rate of 0.32℃/decade and precipitation has increased at a rate of 9.32 mm/decade. The glaciers are shrinking at accelerating rate and the runoff supplied by glacier/snow meltwater has increased. The amount of water resources has increased by about 11 billion m3 since the mid-1990s. In the past decade, water use efficiency has been improved, water-saving irrigation area has been expanded, and agricultural water production efficiency has been improved due to water conservation and utilization measures. Water environment capacity has been increased, water carrying capacity has been enhanced, surface water area has been expanded, and the ecosystem condition has improved. However, water resources problems are still prominent in the arid region of Northwest China, the intensity of extreme climate and hydrological events has increased, and the ecological environment is still fragile. In the future, it is necessary to further explore the water resources potential of this region, improve the water resources management, and enhance ecological protection and restoration efforts for better adaptation to the possible risks of climate change, so as to provide scientific and technological support for promoting the construction of the “Green Silk Road” and realizing high-quality regional economic and social development.
Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract： The Luancheng Agro-Ecosystem Experimental Station, the Chinese Academy of Sciences, is located in the piedmont plain area of North China Plain and the middle section of the Taihang Mountain alluvial plain. It is a typical representative of the high-yield agricultural eco-system in the groundwater irrigation area. Due to the large-scale and high-intensity agricultural production in recent decades, the regional groundwater has been seriously over exploited, and the risk of groundwater pollution has increased. However, the surface agro-ecosystem and aquifer are separated by thick vadose zones, hence the mechanism of the impact of surface agricultural activities on the quantity and quality of groundwater is still unclear. The in-situ monitoring throughout the entire vadose zone is the only method to reveal the mechanism of this process. Therefore, the establishment of a large-scale critical zone observatory is the most important requisite for conducting research on the relationship between agriculture and groundwater. With the support of the corner#2;stone research infrastructure project for the field station network of the Chinese Academy of Sciences, Luancheng Station began to construct the “Water and Solute Cycle Observation Platform in Groundwater-Soil-Crop System” in 2016, and the construction was completed in November 2020. An observatory caisson with a depth of 48 m and an inner diameter of 2.8 m has been built. The platform was officially named ‘Luancheng Critical Zone Observatory’ (LC-CZO). LC-CZO can measure the key variables such as soil water content, matric potential, soil temperature, and solute concentration in the root zone-deep vadose zone-saturated zone. The monitoring results enable the study on the patterns of the transport and transformation of water,solutes and pollutants in the thick vadose zone reveal the hydrological process of the saturated-unsaturated transition zone and its relationship with groundwater replenishment, explain the migration and transformation of nitrogen applied in farmland and its impact on groundwater quality, and provide experimental platform support for exploring the impact mechanism of land surface process on the groundwater quantity and quality.
Subjects: Other Disciplines >> Synthetic discipline submitted time 2018-06-24 Cooperative journals: 《中国科学院院刊》
Abstract：华北平原农业的高强度水肥投入造成严重地下水超采和氮素污染风险。中国科学院栾城农业生态系统试验站立足农田生态系统的长期生态学监测和研究，围绕农业资源高效利用和可持续发展，建立了农田土壤-作物-大气系统（SPAC）界面节水调控理论与技术，提出基于农田水平衡的休耕轮作和适水型种植制度调整思路，阐明了农田碳氮循环特征和温室气体排放及硝酸盐淋失通量，在厚包气带水盐运移和硝酸盐转化和削减机理方面取得突破性认识，研发了农田生产信息快速获取和精准管理的技术产品与平台，并与农业发展紧密结合，集成了系列农业生产技术模式，为区域农业的优质高效发展和水资源可持续利用提供了理论和技术支撑。
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Basic Disciplines of Agriculture submitted time 2017-11-09 Cooperative journals: 《中国生态农业学报》
Abstract：光合作用是衡量植物对环境响应的重要指标, 通过光响应曲线拟合量化光合特征, 可从生理机制方面揭示出植物在不同生长环境下自身的调节与适应机制。本文利用Li-6400 便携式光合仪测定了冬小麦在4 种不同处理条件下灌浆期旗叶的光响应曲线, 采用直角双曲线模型(RHM)、非直角双曲线模型(NRHM)、直角双曲线修正模型(RHMM)、指数模型(EM)和指数改进模型(MEM)对光响应数据进行拟合, 分析了不同CO2 浓度和土壤含水量对冬小麦光合特征的影响。结果表明, 直角双曲线修正模型对各处理下冬小麦光响应曲线和光响应曲线参数的拟合值都与实测值较为接近, 拟合效果最好; 随着CO2 浓度升高, 各水分处理下冬小麦表观量子效率(α)、光饱和点(LSP)和最大净光合速率(Pnmax)增大, 光补偿点(LCP)和暗呼吸(Rd)降低, 即CO2 浓度升高能有效增加冬小麦的光能转化率和光能利用范围, 提高冬小麦的光合能力; 随着土壤含水量的降低, 冬小麦光补偿点(LCP)和暗呼吸速率(Rd)升高, 但表观量子效率(α)、光饱和点(LSP)和最大净光合速率(Pnmax)降低,即冬小麦虽然能通过提高初始光合效率抵消一部分干旱胁迫的影响, 但干旱胁迫仍会降低冬小麦光合能力;此外, CO2 浓度的增加能抵消部分冬小麦因干旱胁迫引起的光合能力降低。
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Basic Disciplines of Agriculture submitted time 2017-11-09 Cooperative journals: 《中国生态农业学报》
Abstract：光合作用是衡量植物对环境响应的重要指标, 通过光响应曲线拟合量化光合特征, 可从生理机制方面揭示出植物在不同生长环境下自身的调节与适应机制。本文利用Li-6400 便携式光合仪测定了冬小麦在4 种不同处理条件下灌浆期旗叶的光响应曲线, 采用直角双曲线模型(RHM)、非直角双曲线模型(NRHM)、直角双曲线修正模型(RHMM)、指数模型(EM)和指数改进模型(MEM)对光响应数据进行拟合, 分析了不同CO2 浓度和土壤含水量对冬小麦光合特征的影响。结果表明, 直角双曲线修正模型对各处理下冬小麦光响应曲线和光响应曲线参数的拟合值都与实测值较为接近, 拟合效果最好; 随着CO2 浓度升高, 各水分处理下冬小麦表观量子效率(α)、光饱和点(LSP)和最大净光合速率(Pnmax)增大, 光补偿点(LCP)和暗呼吸(Rd)降低, 即CO2 浓度升高能有效增加冬小麦的光能转化率和光能利用范围, 提高冬小麦的光合能力; 随着土壤含水量的降低, 冬小麦光补偿点(LCP)和暗呼吸速率(Rd)升高, 但表观量子效率(α)、光饱和点(LSP)和最大净光合速率(Pnmax)降低,即冬小麦虽然能通过提高初始光合效率抵消一部分干旱胁迫的影响, 但干旱胁迫仍会降低冬小麦光合能力;此外, CO2 浓度的增加能抵消部分冬小麦因干旱胁迫引起的光合能力降低。
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Basic Disciplines of Agriculture submitted time 2017-11-09 Cooperative journals: 《中国生态农业学报》
Abstract：蒸散发(ET)是陆地水循环过程的重要组成部分, 同时也是区域能量平衡以及水量平衡的关键环节, 精确估算ET, 对于提高水分利用效率以及优化区域用水结构具有重要意义。本文利用黑河重大计划观测数据, 对比了考虑CO2 浓度和不考虑CO2 浓度对玉米冠层影响的冠层阻力模型, 分别将其耦合到双源的Shuttleworth-Wallace(S-W)模型中, 并利用这两种模型分时段对玉米整个生育期内半小时尺度上的ET 进行模拟,利用涡度相关实测数据对模型进行验证, 最后分别对影响玉米冠层阻力的气象要素和影响ET的阻力参数进行敏感性分析, 探寻大气CO2 浓度改变条件下黑河中游绿洲区玉米不同生长阶段的农田耗水规律。结果表明: 本文所修正的考虑CO2 浓度对玉米冠层影响的冠层阻力模型耦合到S-W 模型后, 能够较精准地模拟玉米整个生育期不同生长阶段半小时尺度上农田耗水过程。敏感性分析表明: 各生长阶段冠层阻力( crs )和冠层面高度到参考面高度间的空气动力阻力( ara )对ET的影响最为强烈, 其他阻力参数对ET的影响不明显, ET的变化程度随着 crs 和 ara的增大而减小。本文所修正的考虑CO2 浓度影响的分时段双源模型能够精准地模拟玉米整个生育期各生长阶段的ET, 可为种植结构调整和土地利用方式改变以及CO2 浓度变化环境下的农田蒸散研究提供参考。
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Basic Disciplines of Agriculture submitted time 2017-11-08 Cooperative journals: 《中国生态农业学报》
Abstract：蒸散发(ET)是区域能量平衡以及水量平衡的关键环节, 精确估算蒸散发, 对于提高水分利用效率以及优化区域用水结构具有重要意义, 而冠层阻抗则是准确估算蒸散发的一个重要变量。为了确定冠层阻抗模型区域适用性、解决其参数化问题, 本研究基于黑河重大研究计划已有的通量观测数据, 以Irmak 模型为基础,考虑微气象因子与冠层阻抗之间的关系, 增加了大气CO2 浓度对冠层阻抗的影响, 构建了未考虑CO2 和考虑CO2 影响的两种Irmak 模型, 并将其与Penman-Monteith(P-M)模型耦合, 利用已有涡度相关数据, 分析和检验了两种冠层阻抗模型对环境变量和大气CO2 浓度响应的模拟结果, 并对模型参数进行敏感性分析。结果表明:将考虑大气CO2 浓度影响的Irmak 模型与Penman-Monteith 模型耦合, 能够更好地模拟玉米冠层阻抗和蒸散量对外部环境变量的响应过程。在参数率定期该模型所模拟的冠层阻抗和蒸散量与实测值之间的R2 分别达0.76和0.95, RMSE 分别达33.1 s·m1 和34.5 W·m2; 模型验证期冠层阻抗和蒸散量模拟值与实测值之间的R2 分别达0.68 和0.90, RMSE 分别达63.2 s·m1 和49.0 W·m2。两个独立验证点结果表明考虑了大气CO2 浓度影响的Irmak 模型具有较好的空间可移植性和适应性, 模型能够较为准确地模拟玉米在整个生长季半小时时间尺度上的农田耗水过程。敏感性分析表明玉米冠层阻抗及其蒸散量对净辐射和相对湿度变化最为敏感, 其次是气温、叶面积指数和大气CO2 浓度。本文所构建的考虑大气CO2 浓度对于玉米冠层阻抗影响的Irmak 模型能够较为准确地估算作物蒸散量, 并可为种植结构调整、土地利用方式改变以及大气CO2 浓度变化环境下的农田耗水研究提供一定的研究依据。
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Basic Disciplines of Agriculture submitted time 2017-10-20 Cooperative journals: 《中国生态农业学报》
Abstract：本文基于2000—2013 年MODIS/NDVI 遥感信息与主要粮食作物的统计数据, 分析了河北平原中低产区冬小麦和玉米生产的时空格局, 并利用各县粮食作物主要生育期累积NDVI 的逐年值、14 年的最大值及单产统计数据, 采用最小二乘法原理, 进行数值曲线拟合, 构建了单产遥感估测模型, 估算了河北平原中低产区冬小麦和玉米的增产潜力。结果表明: 1)冬小麦在邯郸和衡水的最大生产力水平较高, 在沧州、廊坊及邢台中部的最大生产力水平较低, 即后者挖掘增产潜力之后也很难达到前者的最大生产力水平; 玉米的最大生产力水平普遍较高, 挖掘增产潜力后均可达到较高的生产力水平。2)冬小麦和玉米总产增产潜力在沧州和邯郸较大; 冬小麦单产增产潜力多低于10%, 平均增产356 kghm2(5.87%); 玉米单产增产潜力多高于10%, 平均增产798 kghm2(12.33%); 单产增产潜力区域分布不同, 冬小麦为廊坊>保定>沧州>邯郸>邢台>衡水, 玉米为邢台>邯郸>保定>沧州>衡水>廊坊。3)以河北平原近14 年来作物累积NDVI 的最大值估算的全区冬小麦增产潜力为3.90 亿kg, 玉米增产潜力为9.62 亿kg, 二者合计可增产13.52 亿kg, 约相当于区域冬小麦和玉米理论可达增产潜力的1/5。本文估测粮食作物增产潜力的方法可以应用于估测多尺度范围、不同作物的增产潜力, 研究结果可为相关部门的决策和管理提供依据。
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