海南中部生态核心区流域水资源横向生态补偿方法

流域水资源生态补偿是促进流域生态环境保护、区域经济可持续发展的必要举措。本文以海南中部生态核心区的琼中黎族苗族自治县为例,综合应用遥感、GIS和SWAT水文模型等技术手段,探讨了流域水资源横向生态补偿所涉及的相关问题和解决方法。利用GIS的流域结构分析和空间叠加分析方法分别勾画、确定了琼中下游万泉河流域、昌化江流域和南渡江流域的范围及下游的相关市县,明确了生态补偿实施的主体构成。利用SWAT水文模型计算得出琼中县多年下游输水量为43.73×10~8m~3·a~(-1),万泉河流域、南渡江流域、昌化江流域输水量分别占总水量的74%、14%和12%。通过对琼中县施行的植树造林、农村环境综合整治、水源地保护等多项水环境生态保护项目投入的核算以及"两个暂停"政策下的机会成本计算,构建了基于成本核算法的琼中县水资源横向生态补偿总量计算模型,按照先流域、后市县的办法,根据下游输水量和生产用水指标构建了下游市县补偿份额分配模型并计算了下游各市县分担的横向生态补偿量。本研究可为水源地型流域水资源横向补偿的实施提供参考。     

密云水库上游流域生态系统服务功能空间特征及其与居民福祉的关系

生态系统管理的一个重要挑战是在区域尺度上管理生态系统服务并提高当地居民福祉。以2009年土地利用数据和社会经济数据为基础,利用InVEST模型和空间制图在乡镇尺度上对密云水库上游流域水资源供给服务、土壤保持服务、水质净化服务、产品供给服务以及居民福祉进行了定量评估和空间特征刻画,并探讨了生态系统服务与居民福祉的不同关系模式。结果表明,流域内各乡镇土壤保持服务从上游到下游呈逐渐递增的趋势,水质净化服务从上游到下游整体上也呈逐渐递增的趋势,流域内水质净化服务功能与水资源供给服务、粮食供给服务、蔬菜供给服务以及畜牧产品供给服务在空间上呈显著负相关;基于生态系统服务与居民福祉在空间上的聚集特征,可将56个乡镇划分为低服务低福祉模式、供给服务依赖模式和高服务高福祉模式,针对这3种关系模式特点,可分别提出改善生态系统服务功能和居民福祉的管理措施。案例研究可为其他区域实施分区管理、协调生态系统服务功能保护与居民福祉的关系提供借鉴。     

流域生态服务价值供给的补偿标准评估——以渭河流域上游为例

十九大报告明确提出,健全河流湖泊休养生息制度,建立多元化的生态补偿机制,而准确核算流域生态服务价值供给的补偿标准是建立科学的流域生态补偿机制的关键要素。对于补偿标准的核算,鲜有学者从公平的视角出发,考虑补偿标准应在生态服务价值供给的基础上剔除本地区的自身消费。首先对流域生态服务供给方的供给行为与流域生态补偿标准的评估依据进行理论探讨,提出流域生态补偿标准应以生态环境价值为依据,对生态保护行为的生态外溢环境价值进行补偿;其次,在理论分析的基础上以渭河流域为例,构建当量因子模型测算渭河上游2006—2015年供给的生态服务价值,并结合水足迹法测算并剔除2006—2015年渭河上游自身消费的生态服务价值;最后,测得渭河上游应获得的补偿标准由2006年的12.82亿元上升至2015年的44.09亿元,总体呈增长趋势,说明上游为保护流域生态环境不断付出努力,不断增加对下游的剩余生态服务价值供给。     

基于分布式水文模型和福利成本法的生态补偿空间选择研究

空间选择是生态补偿研究的核心问题之一,选择合理的区域进行生态补偿有利于提高生态补偿项目的效率.以黑河流域上游肃南县为研究区域,运用分布式水文模型Soil and Water Assessment Tool(SWAT)对研究区实施生态补偿后的水源涵养增加量进行模拟,同时考虑土地利用类型转化成本以及生态系统服务丧失风险,采用福利成本法对研究区生态补偿空间选择进行研究.结果表明:黑河上游肃南段内不同子流域的生态补偿效率系数最高值为0.0394,最低值0.0131,相差明显;根据效率系数,采用聚类分析方法,可将各子流域划分为优先补偿区、次级优先补偿区和潜在补偿区,分批进行补偿;采用空间选择后生态补偿效率较不采用时可提高54.5％.     

基于选择容量价值的生态补偿标准与自然资源资产价值核算——以珠江水资源供应为例

选择容量价值是指,一项人类生存生产所必需的生态系统服务,其总量为消费该生态系统服务的消费活动所提供的选择自由度(即选择容量,optional capacity)与该消费活动所产生的经济社会价值的乘积。选择容量价值将经济发展状况和资源环境状况融合了起来,实现了经济社会发展与生态环境保护的价值统一,这对于推进保护与发展相辅相成的生态文明建设具有积极意义。为了探索以选择容量价值为指标的生态补偿标准与自然资源资产价值核算框架和核算方法,以珠江流域水资源供应为例,对跨水文单元的水资源供应流动进行了生态补偿核算,对各水文单元的水资源供应的自然资源资产价值进行了量化评估研究。研究结果显示,珠江三角洲地区的水资源供应的选择容量价值大部分(约74%)来自上游水文单元的跨区输入,而上游水文单元所提供的水资源供应的选择容量价值也在相当程度上依赖于下游水文单元的经济社会发展。基于跨区流动的水资源供应的选择容量价值,可以按照"共享共担"和"同工同酬"原则进行跨区生态补偿核算;基于各水文单元所提供的水资源供应的选择容量价值,可以对各单元内自然资源资产价值进行核定,这对于协调区域发展推进西江-珠江经济带流域生态文明建设具有重要意义。     

西庄河山地流域水资源供需动态初步研究

水资源的合理有效利用是我国西部生态环境建设中的关键问题。位于怒江流域的西庄河是典型山地小流域 ,山地流域内常常是潜在的水资源十分丰富 ,但现实的水资源却严重缺乏 ,流域内许多村社都面临农业灌溉用水和人畜饮水紧缺的问题。以西庄河流域为例 ,通过定量监测研究山地流域水资源的时空变化规律 ,并通过供需现状参与式评估探讨山地流域的水资源的可持续利用和保护。     

流域水环境管理保护线与控制线及其规划方法

社会经济的发展以及公众环境意识的不断提高,对水质及水环境的要求不断提升,水资源及其环境问题已成为制约我国社会经济可持续发展的瓶颈因素.但在水体保护和管理方面,一直以来缺乏适当的方法或者规范来确定明确的范围与界线,因而难以对水体进行有效的保护和管理.提出流域水环境管理保护线和控制线的概念,与城市蓝线类似,是对流域内江、河、湖、库、渠和湿地等地表水体进行严格保护和控制的地域界线,但在流域水环境综合管理的基础上拓展了其内涵,强调以流域为单元.保护线宽度较小,线内设计植被带,类似于河岸植被缓冲带的概念,对水体及水环境起着缓冲及保护的关键作用;控制线范围较宽,其作用主要在于控制区域内的土地利用及社会经济活动科学有序进行,在社会经济发展的同时不以牺牲水环境为代价.综合考虑流域内生态环境、社会安全、经济发展等因素,结合岸线控制、河岸缓冲带等内容探讨了流域内水环境管理保护线和控制线确定的方法,并以鄱阳湖流域为对象进行了案例研究,取得了较好的结果.表明本文提出的概念和相关规划方法可有效指导流域水环境保护的实践工作,并为各类规划和政策的制定提供科学参考.     

基于赤水河流域生态补偿的政府和社会资本合作项目风险识别与分担

赤水河流域为生态脆弱区域,现行的流域生态补偿机制存在补偿资金来源单一、总量不足且持续性较差、补偿方式较为单一等问题。将政府和社会资本合作（Public-Private Partnership,PPP）模式应用于建立赤水河流域生态补偿机制,有助于拓宽补偿资金来源、增加资金总量、丰富补偿方式,推动各利益相关方收益共享、风险共担。与传统PPP项目相比,基于流域生态补偿的PPP项目具有更为复杂的风险结构,风险因素的正确识别和合理分担是成功运用PPP模式完善赤水河流域生态补偿机制的关键。识别基于赤水河流域生态补偿的PPP项目运作关键环节,甄别各环节面临的主要风险因素;基于云理论建立风险分担模型;将有关风险在政府和社会资本间进行分担。研究结果表明：（1）基于赤水河流域生态补偿的PPP项目运作过程共包括项目准备、项目实施和项目合同终结等三个阶段、共11个关键环节,各环节共面临26个主要风险因素。（2）分析了有关风险因素可能对赤水河流域生态补偿机制或PPP项目产生的不利影响,并指出了风险引致方。（3）在项目准备阶段,政府拥有绝对的资源优势,以政府为主承担主要风险;在项目实施阶段,项目风险总体上由政府承担为主向社会资本承担为主转移,80%的风险主要由社会资本承担;特许经营期满后,社会资本将项目的经营权（或所有权与经营权同时）向政府移交,在项目合同终结阶段,有关风险再次以政府承担为主。     

黑河流域水资源承载能力分析

黑河流域属资源性缺水地区,区域水资源难以满足当地社会经济发展和生态平衡的需要.随着西部大开发战略的逐步实施,西北干旱内陆河地区水资源的支撑作用将显得愈来愈重要.因此分析黑河流域水资源现状条件下对区域经济、社会发展的承载能力,显得极为重要.根据黑河流域具体情况,结合流域经济社会发展特点、生态环境状况,以遏制并逐步改善流域生态环境为基本前提,以流域水资源承载能力为约束.首先利用水资源承载压力指数计算了现状条件下黑河流域水资源承载压力度,得出目前黑河流域水资源承载能力属于超负荷承载.水资源将成为制约黑河流域社会经济发展和保证生态平衡的重要因素.当前必须立足于当地的水资源条件,按照以供定需的原则,合理安排生活、生产和生态用水,才能实现流域经济社会和生态环境的协调和可持续发展.然后针对超载现状,对黑河流域规划水平年（2010年）水资源承载能力作进一步的分析评价,根据相关预测资料设计了3种可能情景,利用流域评价的发展系数、协调系数、公平系数和可持续发展系数,从水资源开发利用方式、社会发展方式、经济发展模式、生态恢复程度等方面分析水资源承载能力,并计算其水资源承载压力度,同时结合水资源的可持续发展建立流域可持续发展评价指标体系,进行方案组合和各种发展模式的水资源优化配置.满足流域水资源支撑经济社会可持续发展判据的方案的承载能力指标即为该方案下的水资源可持续承载能力指标. 通过对黑河流域现状及规划水平年的水资源承载能力及可持续发展度分析评价,利用水资源可持续发展战略分析,选取出了最优发展模式,为流域的可持续发展提供了基本依据.通过寻求情景方案中水资源承载能力和可持续发展度的最佳组合,实现了经济、社会与生态的可持续发展目标.结果表明：通过努力,谋求经济和社会与水资源承载能力协调发展是有可能实现的.     

地表水资源供给服务供需关系对节水政策的响应——以大清河流域为例

水资源是基础性自然资源和战略资源,科学量化水资源供给服务的供需关系、识别供需矛盾的突出区域是进行流域水资源管理的重要前提。以大清河流域为例,利用InVEST模型,建立了水资源供给服务空间流动量化方法,预测了用水效率提升、节水灌溉两种节水政策情景对水资源供给服务供需关系的影响。结果表明：(1)流域水资源供给服务和水资源需求量均呈现出上游低、下游高的空间分布格局,农业用水为流域主要用水类型,2010—2015年,流域水资源供给服务增长0.97%,水资源需求量出现了9.6%的下降;(2)2010—2015年,流域整体水资源供给服务的供需比由0.78提升至0.88,服务的空间流动使得上游盈余的水量缓解了中下游的用水压力,但中下游水资源需求大于供给的问题仍普遍存在;(3)提升用水效率、推行节水灌溉这两种节水政策均能够有效改善大清河流域的水资源供需关系,分别可将流域水资源供需比提升至0.97和0.96,基本达到供需平衡。研究可为北方资源型缺水流域水资源供需匹配度的提高、节水政策潜力的评估提供借鉴。     

气候变化背景下东北三省主要粮食作物产量潜力及资源利用效率比较

以东北地区喜温作物和喜凉作物的潜在种植区为研究区域,基于研究区域内65个气象台站1961—2010年地面气象观测数据,结合作物生育期资料,应用作物产量潜力逐级订正法,分析不同作物各级产量潜力时空分布特征,明确作物各级产量潜力受气候资源限制程度,比较气候资源利用效率差异.结果表明： 1961—2010年,东北三省6种作物（玉米、水稻、春小麦、高粱、谷子和大豆）的光温产量潜力呈明显的西高东低的空间分布特征,作物气候产量潜力除春小麦外其他作物均呈现南高北低的空间分布规律.6种作物受温度限制的产量潜力损失率呈东高西低的空间分布特征,大豆受温度限制引起的产量潜力损失率最高,平均为51%,其他作物为33%～41%;因降水制约引起的潜力损失率分布有明显的区域性差异,在松嫩平原和长白山区各有一个高值区,春小麦因降水亏缺引起的产量潜力损失率最高,平均为50%,其他4种雨养作物集中在8%～10%.东北三省各作物生长季内光能利用效率在0.9%～2.7%,其中玉米>高粱>水稻>谷子>春小麦>大豆;雨养条件下,玉米、高粱、春小麦、谷子和大豆各作物的降水利用效率在8～35 kg·hm^-2·mm^-1,其中玉米>高粱>春小麦>谷子>大豆.在光能利用效率和降水利用效率均较低的长白山区和小兴安岭南部地区,可采取合理密植、选择适宜品种、适时施肥、蓄水保墒耕作以及优化作物布局等措施提高资源利用效率.     

Yield components in Hevea brasiliensis– theoretical considerations

Abstract A theoretical analysis of yield components of Hevea brasiliensis is attempted in this paper. The effect of the major yield components, i.e. initial flow rate per unit length of tapping cut, length of the cut, percentage rubber content and plugging index on rubber yield is represented by the formula Variation in yield within and between clones can be ascribed to variation to any one of the above components. The importance of high growth rate for maintaining high yield throughout the life cycle of the tree is theoretically elucidated. While the present contention of a theoretical maximum yield of 9.5 t ha^?1 with a stand of 350 trees is questioned, the theoretical possibility of attaining that yield by increasing the stand per ha to 600 is analysed.     

Breeding for Yield Potential and Stress Adaptation in Cereals

The need to accelerate breeding for increased yield potential and better adaptation to drought and other abiotic stresses is an issue of increasing urgency. As the population continues to grow rapidly, the pressure on resources (mainly untouched land and water) is also increasing, and potential climate change poses further challenges. We discuss ways to improve the efficiency of crop breeding through a better physiological understanding by both conventional and molecular methods. Thus the review highlights the physiological basis of crop yield and its response to stresses, with special emphasis on drought. This is not just because physiology forms the basis of proper phenotyping, one of the pillars of breeding, but because a full understanding of physiology is also needed, for example, to design the traits targeted by molecular breeding approaches such as marker-assisted selection (MAS) or plant transformation or the way these traits are evaluated. Most of the information in this review deals with cereals, since they include the world's main crops, however, examples from other crops are also included. Topics covered by the review include the conceptual framework for identifying secondary traits associated with yield potential and stress adaptation, and how to measure these secondary traits in practice. The second part of the review deals with the real role of molecular breeding for complex traits from a physiological perspective. This part examines current developments in MAS and quantitative trait loci (QTL) detection as well as plant transformation. Emphasis is placed on the current limitations of these molecular approaches to improving stress adaptation and yield potential. The essay ends by presenting some ideas regarding future avenues for crop breeding given the current and possible future challenges, and on a multidisciplinary approach where physiological knowledge and proper phenotyping play a major role.     

Physiological traits contributed to the recent increase in yield potential of winter wheat from Henan Province,China

This experiment aims to test the traits responsible for the increase in yield potential of winter wheat released in Henan Province, China. Seven established cultivars released in the last 20 years and three advanced lines were assayed. The results showed that grain yield was positively correlated with harvest index(HI), kernel number per square meter, and aboveground biomass. In addition, the HI and aboveground biomass showed an increasing trend with the year of release.Therefore, we can conclude that bread wheat breeding advances during recent decades in Henan Province, China,have been achieved through an increase in HI, kernel number per square meter, and aboveground biomass. A higher d13C seems also to be involved in these advances, which suggests a progressive improvement in constitutive water use efficiency not associated with a trend towards lower stomatal conductance in the most recent genotypes. However, genetic advance Researchdoes not appear related to changes in photosynthesis rates on area basis when measured in the flag leaf or the spike,but only to a higher, whole‐spike photosynthesis. Results also indirectly support the concept that under potential yield conditions, the spike contributed more than the flag leaf to kernel formation.     

Physiological traits contributed to the recent increase in yield potential of winter wheat from Henan Province,China

This experiment aims to test the traits responsible for the increase in yield potential of winter wheat released in Henan Province, China. Seven established cultivars released in the last 20 years and three advanced lines were assayed. The results showed that grain yield was positively correlated with harvest index（HI）, kernel number per square meter, and aboveground biomass. In addition, the HI and aboveground biomass showed an increasing trend with the year of release.Therefore, we can conclude that bread wheat breeding advances during recent decades in Henan Province, China,have been achieved through an increase in HI, kernel number per square meter, and aboveground biomass. A higher d13C seems also to be involved in these advances, which suggests a progressive improvement in constitutive water use efficiency not associated with a trend towards lower stomatal conductance in the most recent genotypes. However, genetic advance Researchdoes not appear related to changes in photosynthesis rates on area basis when measured in the flag leaf or the spike,but only to a higher, whole‐spike photosynthesis. Results also indirectly support the concept that under potential yield conditions, the spike contributed more than the flag leaf to kernel formation.     

Free space uptake and influx of Ni2+ in excised barley roots

The effects of switches between high and low nutrient supplies on growth and mineral nutrition of winter wheat ( Triticum aestivum L. cv. Martonvásári-8) were followed in four main developmental phases: tillering, shooting, heading and grain filling. Growth of the shoots was significantly affected by switches. Under low nutrient supply the life cycle was shortened. Root growth was only slightly affected by switches, but an early high nutrient supply followed by low nutrient supply gave an impetus for root development. In general, the growth data indicate that the nutrient status of the plants is determined by the nutrient level supplied during shooting. A high level of nutrients during shooting leads also to high vegetative growth, whereas the best grain yield was obtained by a high dose of nutrients during tillering followed by low nutrient conditions during the shooting stage and later. K⁺(⁸⁶Rb) influx in the roots decreased with age. The potential for K⁺ (⁸⁶Rb) influx was low in plants of high-salt status, but it became high in response to switching to low supply at shooting, whereas later switches had no influence on this function in high-salt plants. The highest K⁺(⁸⁶Rb) influx was found in plants starting with high nutrient supply followed by low-salt conditions; this plant group was outstanding also with respect to its high grain yield.     

Maize potential yields and yield gaps in the changing climate of northeast China

Northeast China (NEC) is not only one of the major agricultural production areas in China, but it is also the most susceptible to climate variability. This led us to investigate the impact of climate change on maize potential yield and yield gaps in this region, where maize accounts for about 30% of the nation's production. The APSIM‐Maize model was calibrated and validated for maize phenology and yields. The validated model was then used to estimate potential yields, rain‐fed potential yields, and yield gaps for assessing the climate impacts on maize productivity in NEC. During maize growing seasons from 1981 to 2010, the analysis indicates a warming trend all across NEC, whereas the trends in solar radiation and total precipitation tended to decrease. When the same hybrid was specified in APSIM for all years, a simulated increase of maximum temperature resulted in a negative impact on both potential yield and rain‐fed potential yield. A simulated increase in minimum temperature produced no significant changes in potential or rain‐fed potential yield. However, the increase of minimum temperature was shown to result in a positive impact on the on‐farm yield, consistent with our finding that farmers adopted longer season hybrids for which the increase in minimum temperature provided better conditions for germination, emergence, and grain filling during night time. The gap between potential and rain‐fed potential yields was shown to be larger at locations with lower seasonal precipitation (<500 mm). Our results indicate that regions with the largest yield gaps between rain‐fed potential and on‐farm yields were located in the southeast of NEC. Within NEC, on‐farm maize yields were, on average, only 51% of the potential yields, indicating a large exploitable yield gap, which provides an opportunity to significantly increase production by effective irrigation, fertilization, herbicide, and planting density in NEC.     

Effects of inoculum source,pH, redox potential and headspace di-hydrogen on rumen in vitro fermentation yields

This in vitro study aimed at understanding how abiotic, that is chemical and electrochemical potentials, and biotic factors combine to impact the outputs of rumen volatile fatty acid (VFA). Using a 48-run design optimized by means of an exchange algorithm, the curvilinear effects of pH, Eh and partial pressure of dihydrogen (H₂) on fermentation yields were investigated in 6-h batch cultures of mixed rumen microbes, fed on glucose so as to bypass the enzymatic hydrolysis and conversion steps preceding the glycolytic pathway. The role played by rumen microbiota in the expression of these effects was explored by testing three inocula grown on feeds supplying a microflora adapted to fibre, slowly degradable or readily degradable starch as the dominant dietary polysaccharide. Data were fitted to 2nd-order polynomial models. In fibre-adapted cultures, the yields of major VFA were mainly influenced by pH and H₂ partial pressure, in opposite ways. In wheat grain-adapted cultures, the VFA yields underwent the opposite influences of pH, in a curvilinear way for propionate, and Eh since acetate production yield was not significantly modified by any factor. In maize grain-adapted cultures, acetate production yield was not modified by any factor but H₂ in a quadratic way when the production yields of higher VFA underwent opposite influences of pH and Eh. In conclusion, the effects of environmental factors were dependent on the nature of the inoculum, a major source of variation, and more particularly on its adaptation to high- or low-fibre diets. These effects were loosely interrelated, the pH being the most active factor before the Eh and H₂ partial pressure.     

Paper from Thysanolaena maxima

Thysanolaena maxima (Roxb) (tiger or broom grass), is a tall reed-like perennial grass, grown on shady slopes in forests in India and the Nicobar Islands. Culms are solid, smooth and rounded and up to a height of 4 m. The leaves and the tips are used as fodder; the bushy, fox-tail-like panicles (30–90 cm) are used for making brooms. When the panicles are cut, the stem portion (3–4 m) is left out in the field and is burnt. Fibres, of average 1.25 mm in length at 45% yield (unbleached), could be obtained from this grass. The laboratory handmade paper sheets exhibited good properties, with a burst factor of 30, a breaking length of 3555 m and a tear factor of 106. Hence, it can be suggested that T. maxima may become a potential source of raw material for pulp- and paper-making either alone or in combination with the conventional pulp- and paper-making raw materials. This material could help to meet the future demand for pulp- and paper-making raw material, if properly exploited.