基于WOFOST模型的河北省保定市冬小麦最佳灌溉方案研究

利用WOFOST模型对保定地区冬小麦不同年型灌溉方案进行模拟分析,确定最佳灌溉量及灌溉时间,力争灌溉效益最大化,对缓解农业生产和水资源匮乏的尖锐矛盾尤显重要。文章以河北省保定市为例,应用WO)FOST模型对不同降水年型的2003/2004、2005/2006和2008/2009年3个代表生长季,分别进行一次灌溉、两次灌溉、三次灌溉的不同灌溉方案进行模拟,试图揭示冬小麦产量随灌溉时间及灌溉量的变化规律,选择最佳灌溉方案,为干旱缺水的河北省保定市小麦节水、高产提供理论依据。模拟研究结果表明:在冬小麦全生育期中最佳灌溉时期为拔节—孕穗期和抽穗—灌浆期,这两个时期的灌溉对产量的贡献率最高。与此同时,总结出了既可以满足冬小麦生长又可以获得较大经济效益的两次灌溉及三次灌溉的最佳灌溉方案。     

中亚费尔干纳盆地灌溉气候效应的数值模拟研究

中亚地处干旱气候区,农业生产高度依赖灌溉,然而灌溉对当地气候影响的认识还较为薄弱。为此,针对多雨（2009年）、少雨（2008年）及正常（2007年）年景下中亚典型农业区—费尔干纳盆地暖季（5—9月）的气候,利用嵌入灌溉过程参数化方案并更新土壤参数的WRF模式,分别进行了考虑灌溉过程（称为IRRG试验）与不考虑灌溉过程（称为NATU试验）的模拟试验,并通过对比IRRG与NATU试验之差揭示了灌溉对区域气候的影响。研究发现:（1）灌溉致使暖季地面潜热增加（79.2 W/m2）、感热减少（?61.3 W/m2）,日均气温降低1.7℃,空气比湿升高2 g/kg（约为NATU的36%）,因5—6月为雨季,7—8月为旱季,故7—8月的灌溉量大,冷湿效应略强于5—6月;（2）冷湿效应主要出现在灌溉区域,降温达2℃,增湿达2.4 g/kg,灌区外甚微,同时从地面到高层大气,冷湿效应越来越弱,在约500 hPa（距地面约4000 m）以上冷湿效应消失;（3）在盆地中央平原地区,因灌溉而致空气湿度上升产生的潜在增雨效应与地面冷却产生的对流抑制作用相互抵消,灌溉与无灌溉情景下当地降水无显著差异;灌溉可导致盆地南、北两侧山区降水增加（约0.6 mm/d）;（4）不同年景之间灌溉量差异主要出现在5—6月,少雨年比多雨年灌溉量多20 mm/月,日均气温降幅偏大0.3℃,空气比湿增幅偏大0.5 g/kg,但山区降水增幅偏小0.6 mm/d。      

华北平原地下水灌溉对区域气候影响的数值模拟

在耦合模式WRF/Noah-MP中加入考虑地下水过程的动态灌溉方案,设计两组试验（分别为考虑和不考虑地下水灌溉）,连续模拟10 a（2001—2010年）,来研究华北平原地下水灌溉的区域气候效应。结果表明,地下水灌溉导致华北平原地下水位下降,在少雨的季节灌溉量大,水位下降较快。在灌溉期（3—9月）,灌溉引起的土壤湿度升高影响了地表能量的分配（潜热增加,感热减少）,导致2 m气温显著降低0.6—1.0℃,同时也降低了灌溉区夏季模拟偏高的气温。灌溉对灌溉区边界层大气有升高湿度和冷却降温的作用,对春季的影响局限在边界层内,而夏季的影响持续到5000 m以上。夏季灌溉对降水的影响远强于春季,灌溉的升高湿度和冷却效应分别对夏季降水产生正反馈和负反馈,共同影响灌溉区的降水变化。灌溉通过对水汽输送的影响,引起非灌溉区降水的变化,而长江中下游流域夏季降水的增多可能与高空西风急流轴位置南移有关。      

冬小麦土壤墒情预报及优化灌溉技术的计算机模型

利用土壤水分平衡方程,根据我省冬小麦的生长规律及冬小麦优化灌溉技术推广经验,建立了冬小麦土壤墒情预报及优化灌溉技术的计算机模型.利用该模型,可以较准确地预报未来1个月的土壤墒情变化,并可根据我省小麦的不同发育期给出以最高产量和最佳经济效益为目标的两种灌溉建议.     

沧州地区冬小麦的水分供需特征及水资源的合理利用

本文根据前人的田间试验结果和气象观测资料,应用彭曼公式和气候生产潜力的理论与方法,分析了沧州地区冬小麦水分供需特征,并从理论上探讨了不同时期灌水的生产效率。结果表明:本区小麦冬前水分条件较好,基本上可以满足需要,返青后水分供需矛盾日趋尖锐,返青—成熟各关键期各生育阶段的缺水幅度为88—138mm,产量降低幅度为18—50％。 灌溉的增产作用以拔节—抽穗期最好,在灌溉量相同的情况下,分别比返青—拔节期和抽穗—成熟期灌溉的增产40.6％和18.3％。     

冬小麦土壤墒情预报及优化灌溉技术的计算机模型

利用土壤水分平衡方程，根据我省冬小麦的生长规律及冬小麦优化灌溉技术推广经验，建立了冬小麦土壤墒情预报及优化灌溉技术的计算机模型，利用该模型，可以较准确地预报未来1个月的土壤墒情变化，并可根据我省小麦的不同发育期给出以最高产量和最佳经济效益为目标的两种灌溉建议。     

贵州省淡季种植番茄灌溉量时空分布特征

根据2011—2015年贵州省51个常规地面气象观测站逐日资料及自动土壤水分观测站资料,利用农田土壤水分平衡方程,计算了贵州省淡季番茄生育期灌溉量。简要分析了贵州省淡季番茄灌溉量的空间分布特征,以及不同播种日期番茄灌溉量的时空变化特征;同时利用Python语言对最小灌溉量播种日期进行EOF分析,找到灌溉量最小播种日期及地区,对增加贵州省淡季番茄产量及降低成本有指导性作用。     

鲁中地区冬小麦水分盈亏及灌溉需水量的时空变化特征

利用1980—2014年鲁中地区气象资料和冬小麦生育期资料,采用Penman-Monteith模型和单作物系数计算冬小麦各生育阶段需水量,利用美国农业土壤保持局推荐方法计算有效降水量、水分盈亏指数(CWSDI)和灌溉需水量,对冬小麦不同生育阶段的需水量、有效降水量、水分盈亏指数及灌溉需水量时空变化进行分析。结果表明:近35 a来,鲁中平原地区冬小麦全生育期需水量呈弱的减少趋势,山区呈增加趋势;拔节—乳熟期是需水量最大的阶段,呈减少趋势,强度中心在中部地区。有效降水量全生育期呈减少趋势,拔节—乳熟期呈增加趋势,强度中心在中部地区;除平原地区的越冬期外,其它生育阶段有效降水量呈减少趋势。CWSDI全生育期呈减少趋势,乳熟—成熟期减少幅度最大,自中部向南北两边递减。为满足冬小麦需水要求,全生育期平均灌溉需水量515 mm,呈上升趋势,强度中心在西部地区,拔节—乳熟期是灌溉需水量最大的阶段,呈减少趋势,返青—拔节期是增加趋势最明显的阶段。     

做好灌溉预报 推动节水农业发展

干旱缺水是制约通辽市农业生产的主要问题,水资源短缺与浪费的矛盾日益突出,提高水资源利用率,应对气候变化,发展节水型农业已迫在眉睫。及时准确提供灌溉预报信息是实现节水灌溉的重要环节,也是拓宽气象服务领域的重要内容,对区域农业可持续发展有重要意义。通辽市气象局根据当地气候特点和农业生产的实际,利用内蒙古气象科研所研制的＂内蒙古半干旱区农田优化灌溉预测技术＂,从2005年开始陆续对通辽地区玉米田进行了灌溉信息预报的试验示范工作,取得一定的效果,现总结如下。     

六盘水市近6a马铃薯全生育期的降水特征及其补充灌溉分析

选取贵州西部六枝特区郎节坝试验区、钟山区大地试验区、水城县前进试验区和盘县坡上试验区共4个不同海拔马铃薯种植区连续6 a(2006—2011年)春薯主要大田生长期(2—9月)逐日降水的观测资料和春薯产量资料,利用降水产量积分回归函数,分析降水变化对春薯产量的影响。结果表明,贵州西部山区降水存在时空分布不均状况,但降水总体呈现出随着海拔高度的升高而增多趋势,同时找出了影响春薯产量不稳定的主要原因。不同区域春薯生长发育过程中的最佳补充灌溉时期不同:郎节坝试验区在播种期到开花期需补充灌溉,大地试验区应分别在播种期和现蕾期到开花期补充灌溉,前进试验区在现蕾期到开花期需补充灌溉,坡上试验区应在开花的始期至盛期补充灌溉。科学、合理的调控措施,有利于提高春薯的产量和质量。     

河南省冬小麦灌溉需水量及年型特征

本文以麦田水分平衡为基础,系统分析了冬小麦需水量、生育期降水量和底墒水储藏量3个分量的变化及其对冬小麦灌溉需水量的影响.不同气候年型冬小麦生育期降水量和前一年夏季降水量对冬小麦灌溉需水量有很大的影响.分析结果表明,河南省冬小麦灌溉需水量等值线基本上呈纬向分布,自南向北逐渐增大.正常年零值线大体位于卢氏、嵩县、许昌、鄢陵、柘城至永城一线.在此线以北必须进行灌溉,其灌溉量愈向北愈大,从50-100 mm到 100-200 mm;零值线以南,不需要灌溉.丰水年零值线大约向北移动0.5～0.8个纬距,全省灌溉面积和灌溉量明显减小,零值线以北灌溉量约为50-150 mm;歉水年零值线南移,与正常年相比,大约向南移动1.0～1.5个纬距,灌溉面积和灌溉量明显增大,自零值线向北,灌溉量分别为50-100、100-200 和200 mm以上.     

河西走廊农灌区耕作土壤次生盐渍化成因与防治对策

产生河西走廊耕作土壤次生盐渍化的主要成因。概括起来为大水漫灌、串灌；大块田土地不平整，灌水不均匀；化肥施用量过高；作物耕作制度不合理；土地弃耕和渠道渗漏等。防治对策是平整土地、合理密植、增大有机肥施用量、节水灌溉防止弃耕。     

气候行动最前线的高标准农田生产气象保障

以变暖为主要特征的全球气候变化已经严重威胁到全球粮食安全,高标准农田建设作为农业适应气候变化的重要措施已经在中国推广实施。为助力气候变暖影响下的高标准农田生产,文章梳理了国际土地整理与我国高标准农田建设历程,并从高标准农田适宜性评价、土地要素配置的粮食效应、高标准农田监督管理和高标准农田建设效益评价四个方面综述了高标准农田的最新研究进展,指出目前缺乏高标准农田生产气象保障相关研究。在此基础上,针对高标准农田旱涝保收、抗灾能力强和生态良好“三位一体”的要求,提出气象助力高标准农田生产应加强三个方面研究：农田生态系统-气候-水资源相互作用与农田节水灌溉;主要粮食作物气象灾变精准监测模拟与快速解析归因;农田生态气象风险敏感因子检测及其气象监测评价,以实现气象为农服务提质增效,助力高标准农田高产增效。     

鲁西南历年逐旬土壤自然干旱程度序列模型

近30多年来,由于农田灌溉条件的迅速改善,得到的土壤墒情资料已不能反映自然状态下的土壤墒情变化规律。利用土壤水分平衡方程和Penman公式等计算各旬土壤水分相对盈亏程度并对照2001~2003年在不浇水条件下得到的各旬土壤墒情资料,建立拟和方程,确定了干旱指标,恢复了1970~2003年的逐旬实际干旱序列。结果表明,模拟的逐旬干旱序列较好地滤出了灌溉因素,与实际自然土壤自然干旱程度接近。     

Water Availability,Degree Days,and the Potential Impact of Climate Change on Irrigated Agriculture in California

We use the geo-referenced June Agricultural Survey of the U.S. Department of Agriculture to match values of individual farms in California with a measure of water availability as mediated through irrigation districts, and degree days, a nonlinear transformation of temperature, controlling for other influences on value such as soil quality, to examine the potential effects of climate change on irrigated agriculture in California. Water availability strongly capitalizes into farmland values. The predicted decrease in water availability in the latest climate change scenarios downscaled to California can therefore be expected to have a significant negative impact on the value of farmland.     

Climate response of rainfed versus irrigated farms: the bias of farm heterogeneity in irrigation

Researchers who do not take into account farm heterogeneity in implementing specific climate change adaptation options might significantly bias their findings. To prove this point, this paper focusses on irrigation as an adaptation option to climate change and highlights the fact that there is no such thing as “irrigation.” Instead, different farms consider water management options across a spectrum that ranges from purely rainfed farms to purely irrigated farms with in between the extreme practices such as supplemental irrigation, water conservation practices, and different irrigation techniques. Accounting for such differences is necessary, yet difficult due to a lack of farm-specific data on water management and irrigation. This paper uses unique Farm Accountancy Data Network data of Western European farmers on the proportion of farmland that each farm irrigates. Unlike previous work, this allows taking into account some within-irrigation heterogeneity instead of simply categorizing farms as being “irrigated.” We estimate and compare climate response models based on the Ricardian cross-sectional method for a large range of irrigation categories. The results give insights into how the farm irrigation climate response can be significantly different depending on how irrigation is defined. This proves that ignoring within-adaptation differences when comparing non-adaptation with adaptation (in this case, rainfed versus irrigated agriculture) might lead to biased conclusions with regard to effectiveness of adaptation strategies. We therefore argue that it might be more relevant to understand at which point and under which circumstances irrigated agriculture is more or less beneficial than rainfed agriculture.     

黑河中游荒漠绿洲农业适应气候变化技术研究

以我国第二大内陆河流域——黑河流域的中游荒漠绿洲为例,基于长期定位试验成果,研究了绿洲农业适应气候变化的技术及其潜力。结果表明,在田间水平上,垄沟灌溉种植、主栽作物与伴生植物混播种植、优化水肥管理、建立枣粮复合系统是绿洲农业适应气候变化的有效技术;在绿洲水平上,调整农业种植结构、加大农田林网规格和减少农田林网的灌溉次数、降低防风固沙体系中高耗水树种——杨树的比例等技术是应对气候变化的重要途径。综合评价结果表明,在黑河中游绿洲,通过推广上述技术,在不降低绿洲农业产值和不影响绿洲生态系统稳定性的前提下,初步估算每年可节水2.96×108m3,抵消了气温上升大约1℃所带来的蒸散发消耗量。     

Effects of optimized root water uptake parameterization schemes on water and heat flux simulation in a maize agroecosystem

As root water uptake (RWU) is an important link in the water and heat exchange between plants and ambient air, improving its parameterization is key to enhancing the performance of land surface model simulations. Although different types of RWU functions have been adopted in land surface models, there is no evidence as to which scheme most applicable to maize farmland ecosystems. Based on the 2007–09 data collected at the farmland ecosystem field station in Jinzhou, the RWU function in the Common Land Model (CoLM) was optimized with scheme options in light of factors determining whether roots absorb water from a certain soil layer (W_x) and whether the baseline cumulative root efficiency required for maximum plant transpiration (W_c) is reached. The sensibility of the parameters of the optimization scheme was investigated, and then the effects of the optimized RWU function on water and heat flux simulation were evaluated. The results indicate that the model simulation was not sensitive to W_x but was significantly impacted by W_c. With the original model, soil humidity was somewhat underestimated for precipitation-free days; soil temperature was simulated with obvious interannual and seasonal differences and remarkable underestimations for the maize late-growth stage; and sensible and latent heat fluxes were overestimated and underestimated, respectively, for years with relatively less precipitation, and both were simulated with high accuracy for years with relatively more precipitation. The optimized RWU process resulted in a significant improvement of CoLM’s performance in simulating soil humidity, temperature, sensible heat, and latent heat, for dry years. In conclusion, the optimized RWU scheme available for the CoLM model is applicable to the simulation of water and heat flux for maize farmland ecosystems in arid areas.     

A scale-based framework to understand the promises,pitfalls and paradoxes of irrigation efficiency to meet major water challenges

An effective placement of irrigation efficiency in water management will contribute towards meeting the pre-eminent global water challenges of our time such as addressing water scarcity, boosting crop water productivity and reconciling competing water needs between sectors. However, although irrigation efficiency may appear to be a simple measure of performance and imply dramatic positive benefits, it is not straightforward to understand, measure or apply. For example, hydrological understanding that irrigation losses recycle back to surface and groundwater in river basins attempts to account for scale, but this generalisation cannot be readily translated from one location to another or be considered neutral for farmers sharing local irrigation networks. Because irrigation efficiency (IE) motives, measures, effects and technologies play out at different scales for different people, organisations and purposes, and losses differ from place to place and over time, IE is a contested term, highly changeable and subjective. This makes generalisations for science, management and policy difficult. Accordingly, we propose new definitions for IE and irrigation hydrology and introduce a framework, termed an ‘irrigation efficiency matrix’, comprising five spatial scales and ten dimensions to understand and critique the promises, pitfalls and paradoxes of IE and to unlock its utility for addressing contemporary water challenges.     

Factors driving international technology transfer: empirical insights from a CDM project survey

This study empirically explores factors driving international technology transfer via Clean Development Mechanism (CDM) projects by explicitly considering factors that have been identified in the literature on international technology transfer as being relevant for transfer success. These factors include technological characteristics, such as the novelty and complexity of a technology, as well as the use of different transfer channels. Employing data from an original survey of CDM project participants, the econometric analysis also distinguishes between knowledge and equipment transfer. The findings suggest that more complex technologies and the use of export as a transfer channel are both associated with a higher degree of technology transfer. Projects involving two- to five-year-old technologies seem more likely to involve technology transfer than both younger and older technologies. Energy supply and efficiency projects are correlated with a higher degree of technology transfer than non-energy projects. Unlike previous studies, technology transfer was not related to project size, to the length of time a country has hosted CDM projects, or to the host country's absorptive capacity. The findings for knowledge and equipment transfer are similar, but not identical.

Policy relevance

CDM projects are often seen as a vehicle for the transfer of climate technologies from industrialized to developing countries. Technology transfer is an important element of the new and emerging market mechanisms and frameworks under the United Nations Framework Convention on Climate Change, such as the Technology Mechanism, Nationally Appropriate Mitigation Actions, or Intended Nationally Determined Contributions. Thus, a clearer understanding of the factors driving technology transfer may help policy makers in their design of such mechanisms. For the CDM, this may be achieved by including more stringent technology transfer requirements in countries’ CDM project approval processes. Based on our findings, such policies should focus particularly on energy supply and efficiency technologies. Likewise, it may be beneficial for host countries to condition project approval on the novelty and complexity of technologies and adjust these provisions over time. Since such technological characteristics are not captured systematically by project design documents, using a survey-based evaluation opens up new opportunities for a more holistic and targeted evaluation of technology transfer in CDM projects.