旱作物灌溉用水预测公式

从土壤湿润层水量平衡出发,推导出旱作物灌溉用水预测公式,利用历史实测灌溉用水及同期降雨资料率定有关参数,根据降雨预报资料预测灌溉用水量。方法简便,适用于种植结构不明的灌区,特别是数个灌区构成的灌溉区域。     

气候变化下长江中下游水稻灌溉需水量时空变化特征

选择长江中下游单季中稻为研究对象,结合45个气象站1961~2010年逐日气象资料,基于统计降尺度模型(SDSM),生成HadCM3气候模式A2和B2两种情景下各站点参考作物腾发量和降水数据。基于联合国粮食及农业组织(FAO)推荐的作物系数法,并考虑有效性降雨和不同地区深层渗漏量,分析历史和未来的水稻灌溉需水时空变化特征。结果表明:过去50年,除了太湖流域以外的长江中下游大部分区域的参考作物腾发量和水稻需水量都呈显著下降趋势,而显著下降的水稻灌溉需水量主要位于鄱阳湖流域;未来两种情景下,参考作物腾发量、水稻需水量和水稻灌溉需水量均值都呈下降趋势,但水稻灌溉需水量降幅最小;水稻需水量和水稻灌溉需水量在长江中下游地区的变化趋势具有明显的空间异质性,水稻需水量大幅减少的区域由太湖流域向汉江和洞庭湖流域扩展。未来水稻灌溉需水量减少的区域主要分布在太湖流域、汉江流域东部和洞庭湖流域北部,并随时间推移呈扩大趋势。     

A snapshot of environmental iodine and selenium in La Pampa and San Juan provinces of Argentina

Soil and water samples were collected from farmsteads and provincial towns across the provinces of La Pampa and San Juan in Argentina. Inductively coupled plasma mass spectrometry was used for the determination of iodine in water following addition of TMAH to 1% v/v and soils extracted with 5% TMAH. Iodine in agricultural soils was in the range of 1.3–20.9 mg/kg in La Pampa located in central Argentina and 0.1–10.5 mg/kg in San Juan located in the northwest Andean region of Argentina, compared to a worldwide mean of 2.6 mg/kg. Mean selenium concentrations for soils from both provinces were 0.3 mg/kg, compared to a worldwide mean of 0.4 mg/kg. The majority of soils were slightly alkaline at pH 6.7 to 8.8. The organic content of soils in La Pampa was 2.5–5.9% and in San Juan 0.1–2.3%, whilst, mobile water extractable soil-iodine was 1–18% for La Pampa and 2–42% for San Juan. No simple relationship observed for pH and organic content, but mobile iodine (%) was highest when organic content was low, higher for lower total iodine concentrations and generally highest at pH > 7.5. Water drawn for drinking or irrigation of a variety of crops and pasture was found to range from 52 to 395 µg/L iodine and 0.8 to 21.3 µg/L selenium in La Pampa and 16–95 µg/L iodine and 0.6 to 8.2 µg/L selenium in San Juan. The water samples were all slightly alkaline between pH 8 and 10. Water–iodine concentrations were highest at pH 7.8 to 8.8 and in groundwaters positively correlated with conductivity. Raw water entering water treatment works in La Pampa was reduced in iodine content from approximately 50 µg/L in raw water to 1 µg/L in treated drinking water, similar to levels observed in regions experiencing iodine deficiency.     

Quaternary alluvial terraces in an active tectonic region: the San Juan River Valley,Andean Ranges,San Juan Province,Argentina

The San Juan River, located in San Juan Province (Argentina), crosses the Precordillera and other geologic units including the Ullum tectonic valley and the La Laja Zone between latitudes 31°S and 32°S. The San Juan River is antecedent as is suggested by its two perpendicular segments linked by an almost parallel segment to the main structural trend. Along the Precordillera, the San Juan River valley has many different alluvial fans at the river junctions with its tributaries. The Quaternary alluvial fans display surfaces cut in a series of steps which we consider to be alluvial terraces generated by aggradation and repeated incision episodes. The studied sector includes one area with recent major seismic activity (La Laja Zone), another without major seismic activity (Precordillera area), and a subsident area (Ullum area) where a large lake was formed 6500 yr BP. The old San Juan River was captured by the Quebrada de Ullum valley by means of a 25-m incision, which resulted in river-gradient headward erosion. The San Juan River gradient shows some irregularities that, although unrelated to the main structures, are associated with river dynamics, which emphasizes lithologic differences. The main river valley width, the geometry and gradient of each tributary, together with the basement rock lithologies and the size of each local source area are the major factors which control the alluvial terrace generation processes. In the La Laja Zone, where the uppermost terrace is capped by travertine, dating of travertine deposits suggests that the maximum incision rate is 0.9–1 mm/yr related to episodic activity on the La Laja Fault.     

SRA1B情景下中国主要作物需水预测

分析气候变化下中国主要作物需水规律,有助于从粮食安全与水资源可持续利用角度应对气候变化。根据IPCC提供的SRA1B情景下大气环流模式MIROC3.2的输出,利用FAOPenman-Monteith公式计算参考作物腾发量;根据FAO作物系数、SAGE作物分布与柯本气候分类,得到计算单元的作物系数,根据参考作物腾发量与作物系数估算作物需水量;考虑需水与有效降水旬尺度的随机匹配,预测SRA1B情景下未来50年中国各地区主要作物的灌溉需水量。结果表明,参考作物腾发量总体上呈上升趋势,全国平均增加约8%;作物需水量总体上呈增加趋势,东北地区平均增加约10%;灌溉需水量总体上呈增加趋势,东北与华南增加显著。分析表明,SRA1B情景下气温升高是作物需水量增加的主要原因,降水的增加使华北地区灌溉需水量的增加不显著,降水的减少使东北与华南灌溉需水量显著增加。     

Impact of climate change on irrigation requirements in terms of groundwater resources

Climate change affects not only water resources but also water demand for irrigation. A large proportion of the world’s agriculture depends on groundwater, especially in arid and semi-arid regions. In several regions, aquifer resources face depletion. Groundwater recharge has been viewed as a by-product of irrigation return flow, and with climate change, aquifer storage of such flow will be vital. A general review, for a broad-based audience, is given of work on global warming and groundwater resources, summarizing the methods used to analyze the climate change scenarios and the influence of these predicted changes on groundwater resources around the world (especially the impact on regional groundwater resources and irrigation requirements). Future challenges of adapting to climate change are also discussed. Such challenges include water-resources depletion, increasing irrigation demand, reduced crop yield, and groundwater salinization. The adaptation to and mitigation of these effects is also reported, including useful information for water-resources managers and the development of sustainable groundwater irrigation methods. Rescheduling irrigation according to the season, coordinating the groundwater resources and irrigation demand, developing more accurate and complete modeling prediction methods, and managing the irrigation facilities in different ways would all be considered, based on the particular cases.     

水资源需求驱动因素分析

根据我国1980-2000年国民经济实际用水状况,简要分析了水资源需求的驱动因素,建立了水资源需求驱动因素综合分析模型,并根据模型进行了实例计算和分析.结果表明:(1)1980-2000年全国总用水增加了1 220亿m3,其中工业和生活用水增长是国民经济用水增长的直接原因;(2)全国而言,排在前四位的正向驱动因素分别是工业增加值、农田灌溉面积、人口以及林牧渔需(补)水面积.负向驱动因素分别是农田灌溉定额的下降,其次是工业用水定额的下降;(3)对生活用水而言,北方省份人口增长对生活需水增长的贡献较突出,南方省份则是生活用水定额的提高对生活需水增长的贡献较突出;(4)对工业用水而言,工业规模的扩大是驱动工业需水增长的主要因素;北方省份工业用水定额下降对抑制工业需水增长的贡献率明显;(5)农田灌溉面积变化对农田灌溉需水变化影响较大.分析结果为把握我国未来水资源需求变化态势,合理配置水资源提供依据.     

Testing helium equilibrium between quartz and pore water as a method to determine pore water helium concentrations

The effectiveness of carbon capture and geologic storage depends on many factors, including and especially the permeability of the reservoir’s caprock. While caprock integrity is generally assumed if petroleum has been preserved, it is poorly constrained in reservoirs containing only saline waters, and CO₂ leakage poses a potential risk to shallow aquifers. Naturally-occurring He accumulates in pore waters over time with the concentration being strongly dependent on the long term flux of fluid through the caprock. Furthermore, a small fraction of pore-water He diffuses into quartz and this may be used as a proxy for He concentrations in pore water, where dissolved gas samples are difficult to obtain, such as in deep sedimentary basins. In this paper He contained in quartz grains is measured and compared to previously measured pore water concentrations. Quartz was purified from core samples from the San Juan Basin, New Mexico and the Great Artesian Basin, South Australia. Quartz separates were heated at 290 °C to release He from the quartz. The quartz from the San Juan Basin and high purity quartz from the Spruce Pine Intrusion, North Carolina was repeatedly impregnated at varying pressures using pure He, heated and analyzed to build He sorption isotherms. The isotherms appear linear but vary between samples, possibly due to fluid inclusions within the quartz grains as high purity quartz samples partition only 1.5% of He that partitions into San Juan Basin samples. Concentrations of He in the pore water were calculated using the He-accessible volume of the quartz and the air–water He solubility. The mean San Juan Basin He pore water concentration was 2 × 10^–5 cc STP He/g water, ∼400 times greater than atmospheric solubility. Great Artesian Basin samples contain a mean He concentration of 3 × 10^–6 cc STP He/g water or 65 times greater than atmospheric solubility. However, pore water He concentrations in both the San Juan and Great Artesian Basins differ by up to an order of magnitude compared to samples collected with an alternate method. The reason for the offset is attributable to either partial saturation of the pore volume or a lack of He equilibrium between quartz and pore water. Coating of clay or other mineral phases on quartz grains, which tends to reduce the effective diffusion coefficient, may cause the latter. This technique of assessing permeability is promising due to the abundance of existing core samples from numerous basins where carbon sequestration may ultimately occur.     

Optimal planning and operation of irrigation systems under water resource constraints in Oman considering climatic uncertainty

In this contribution, we introduce a stochastic framework for decision support for optimal planning and operation of water supply in irrigation. This consists of (1) a weather generator for simulating regional impacts of climate change on the basis of IPCC scenarios, (2) a tailor-made evolutionary optimization algorithm for optimal irrigation scheduling with limited water supply, (3) a mechanistic model for simulating water transport and crop growth in a sound manner, and (4) a kernel density estimator for estimating stochastic productivity, profit, and demand functions by a nonparametric method. As a result of several simulation/optimization runs within the framework, we present stochastic crop-water production functions (SCWPF) for different crops which can be used as a basic tool for assessing the impact of climate variability on the risk for the potential yield for specific crops and specific agricultural areas. A case study for an agricultural area in the Al Batinah region of the Sultanate of Oman is used to illustrate these methodologies. In addition, microeconomic impacts of climate change and the vulnerability of the agro-ecological system are discussed.     

Evapotranspiration management based on the application of SWAT for balancing water consumption: A case study in Guantao,China

Rapid social and economic development results in increased demand for water resources. This can lead to the unsustainable development and exploitation of water resources which in turn causes significant environmental problems. Conventional water resource management approaches, such as supply and demand management strategies, frequently fail to restore regional water balance. This paper introduces the concept of water consumption balance, the balance between actual evapotranspiration (ET) and target ET, and establishes a framework to realize regional water balance. The framework consists of three stages: (1) determination of target ET and actual ET; (2) quantification of the water-saving requirements for the region; and (3) reduction of actual ET by implementing various water saving management strategies. Using this framework, a case study was conducted for Guantao County, China. The SWAT model was utilized to aid in the selection of the best water saving management strategy by comparing the ET of different irrigation methods and crop pattern adjustments. Simulation results revealed that determination of SWAT model parameters using remote sensing ET is feasible and that the model is a valuable tool for ET management. Irrigation was found to have a greater influence on the ET of winter wheat as compared to that of maize, indicating that reduction in winter wheat cultivation is the most effective way to reduce regional ET. However, the effect of water-saving irrigation methods on the reduction of ET was not obvious. This indicates that it would be difficult to achieve regional ET reduction using water-saving irrigation methods only. Furthermore, selecting the best water saving management strategy by relying solely on the amount of reduced ET was insufficient, because it ignored the impact of water conservation measures on the livelihood of the agricultural community. Incorporating these considerations with our findings, we recommend changing the current irrigation method to sprinkler irrigation and replacing 20% of the winter wheat-maize cultivated area with cotton, as the best strategy to achieve water balance in the study area.     

煤层气井空气造穴工艺的实践与认识

空气造穴完井是煤层气井所特有的一种行之有效的完井方式,目前在国内外一些地区已经得到有效应用,并取得一定效果,尤其是在美国的圣胡安盆地。但是这种技术也有其局限性,对地质和储层条件要求高,所以在采用该工艺时,不可完全照搬。我国的山西寿阳地区的煤层厚度较大,含气量较高,具有较好的渗透率,且完井深度较浅,使该工艺得以成功实施;而沈北地区虽然煤层较厚,但渗透率低,并受到煤层顶板油页岩物性的影响,空气造穴作业后的返出物体中有大量的顶板油页岩,说明该井的顶板坍塌很严重,这对完井后的排采工作带来极大的隐患和风险,因此,需考虑区内的特殊储层地质条件,对该项技术进行深入的研究,从而提出改进方法。     

冬小麦田咸水灌溉与土壤盐分调控试验

利用浅层咸水灌溉，可使浅层咸水分布区无效降水转化为有效水资源，缓解北方水资源紧缺的矛盾；通过王瞳试验场进行的咸水灌溉与土壤盐分调控试验表明，利用3g/L左右的微咸水连续灌溉5a，根层土壤溶液浓度未超过小麦的耐盐能力，且作物增产；多年盐分变化趋势为：1994－1997年1m深度内土壤总含盐量在一定范围内波动，总体变化不大，连续干旱的1997－1998年略呈上升趋势；麦秸覆盖和施有机肥能减少根层土壤盐分，对土壤盐分具有有利的调控作用，具有增产效果。     

Water Discharge and Sediment Load from the Western Slopes of the Colombian Andes with Focus on Rio San Juan

Small rivers draining high-rainfall basins and mountainous terrain west of the Cordilleras in South America have disproportionately high water discharge and sediment load. Fifteen rivers in western Colombia discharge a combined 254 km3 yr-1 or 8020 m3 s-1 of water into the Pacific. Sediment yield is strongly correlated with basin area (R2=0.97), and sediment load is correlated with water discharge (R2=0.73). Rio San Juan occupies a 16,465-km2 basin with a mean annual rainfall of 7277 mm. It has the highest water discharge (2550 m3 s-1), sediment load (16x106 t yr-1), and basin-wide sediment yield (1150 t km-2 yr-1) on the entire west coast of South America. Rio Patía drains a 23,700-km2 basin with a mean annual rainfall of 2821 mm. Its water discharge, sediment load, and basin-wide sediment yield are 1291 m3 s-1, 14 t yr-1, and 972 t km-2 yr-1, respectively. Rio San Juan and Rio Patía deliver 30x106 t of suspended sediment annually into the Pacific. Analysis of data for an additional 22 rivers in Colombia that drain into the Caribbean Sea indicates that the Pacific rivers have at least twice the sediment yield compared with the larger Rio Magdalena. Our results confirm that the Pacific rivers of Colombia need to be accounted for in global sediment budgets.     

有限供水条件下水库和田间配水整合优化调度

针对多水源多作物灌区,研究有限供水条件下灌区优化配水问题。模型中既考虑水库优化调度,又考虑田间优化配水。模型思路:根据灌区水土资源分布状况,将全灌区划分为多个子区,每个子区种植有若干种作物。如果把每个子区每种作物所在的田块看作一个土壤水库,则可采用水库群调度的方法研究这类灌区优化配水问题,文中采用的是优化控制方法。为了证明模型的正确性,同时建立了3个模型。模型1:既不考虑水库优化调度又不考虑田间优化配水;模型2:只考虑水库优化调度;模型3:只考虑田间优化配水。实例计算表明,整合调度模型能产生较多的效益(特别在干旱年份),优化控制方法计算性能良好。     

Surface water and groundwater dynamic interaction models as guiding tools for optimal conjunctive water use policies in the central plain of Thailand

Many irrigation projects in the central plain of Thailand are not capable of providing sufficient surface water for the cultivation of rice, which is the major cash crop for Thai farmers. To overcome this surface water deficiency, which has been exacerbated in recent years by climate change, groundwater is increasingly being used for irrigation. Thus, large sections of agriculture lands have been converted to conjunctive water use regions. While conjunctive water use may be a suitable option to overcome the temporary water shortages on a short-term basis, it may pose a particular threat to the overall water resources in the long term, if not properly managed. As a remedy, conjunctive water management policies ought to be adopted. Conjunctive water management is basically a tool to optimize productivity, equity, and environmental sustainability through simultaneous management of surface water and groundwater resources. As of now, such a comprehensive approach has not been yet employed in the upper Chao Phraya basin of Thailand, and the present study is one of the first of this kind. The study region is the Plaichumpol Irrigation Project (PIP) where conjunctive water use has become indispensable for meeting the increasing water requirements for farming. To get a first grip on the issue, water demand, supply and actual use in the study area were investigated for the purpose of providing possible guidelines for optimal water exploitation. A numerical groundwater model with a special module for simulating surface-groundwater interaction was applied in the PIP area to understand the impact of the farmer’s irrigation behavior on the dominant hydrological processes that determine the seasonal and multi-annual water availability in the irrigation area. A set-up of different agricultural water allocation schemes that depend on the local weather conditions and the regional management rules are examined by the numerical models. The results of the simulations provide adaptation guidelines for the proper management of the conjunctive water resources, namely, optimal water utilization. The numerical results for the surface groundwater in particular indicated that while the irrigation canals recharge water to the aquifer during both dry and wet season, small amounts of discharge from the aquifers to the canals occur only during the wet season. The analysis of the groundwater balance also showed that the present available groundwater potential is not fully exploited by the farmers, especially during the dry periods of surface water shortage. In contrast, the adoption of an optimal conjunctive management scheme would ensure extra water availability for additional annual rice crops in the region.     

Direct major- and trace-element analyses of rock varnish by high resolution laser ablation inductively-coupled plasma mass spectrometry (LA-ICPMS)

Laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) was used to determine major and trace element concentrations in rock varnish samples from the Lahontan Range, near Fallon, NV and from a remote wilderness area near the San Juan River, in southeastern Utah. The data indicate that rapid LA-ICPMS analyses provide ample analytical resolution for semi-quantitative compositional determinations of both trace and major elements in the varnish despite the presence of a rock substrate component in most analyses. The overall major element contents of rock varnish from the two localities are grossly similar to rock varnish from other locations analyzed by solution ICPMS, electron microprobe, and energy dispersive scanning electron microscopy (SEM). Differences between microprobe and LA-ICPMS analyses may stem from different sampling scales and different degrees of substrate involvement. It was possible to detect significant variations in trace element contents in the rock varnish samples. The Lahontan Range is situated within a belt of W mineralization, and varnish from that locality contained significantly higher W and Mo contents than varnish from localities outside the W belt. Lead, Tl, Bi, Cd and As contents of varnish-coated pebbles from near the San Juan River in southeastern Utah, varied by an order of magnitude as a function of the position of the sampling site on the pebble. Elevated heavy element contents on the skyward-facing varnish surfaces indicate that heavy elements may be preferentially scavenged at the locations most likely to receive direct inputs of atmospherically-deposited airborne particulates. The source of metal-rich airborne particulates, in this case, is probably any one of several large coal-fired power plants in the Four Corners region, proximal to the San Juan study area. These patterns indicate that rock varnish chemistry is influenced by atmospherically-derived fluxes of both dissolved and particulate constituents, and that rock varnish can be used as a passive environmental indicator for a wide variety of elements, in much the same manner as moss and lichens.     

精量灌溉决策定量指标研究现状与进展

按照土壤 植物 大气连续体(SPAC)理论,灌溉决策的指标可分为三类:土壤水分、作物水分生理状况和气象因素。对这三方面的研究现状与进展作了详细的阐述。在土壤水分监测技术方面,时域反射仪(TDR)技术、微波技术、近红外辐射等的应用,使监测更加准确和便利;用于灌溉决策的作物水分生理信息监测包括:细胞液浓度、叶/水势、茎果微变化、生理电阻电容、声发射等,从目前国际上研究情况来看,叶冠层温度和茎流变化是指示作物水分状况较好的指标;在估算大气蒸发力方面,以参考作物蒸散量为指标,估计作物参考蒸散量的方法以联合国粮农组织(FAO)最新推荐的Penman-Monteith方法较为精细。并对目前灌溉决策指标的综合运用情况进行了总结。讨论了作为精准农业重要组成部分的"精量控制灌溉"今后的发展方向,建议以通过对作物、土壤、气象复合系统的分析和判断,指导灌溉的适时和适量。     

独山子地区水资源耦合模型与优化配置研究

本文从水资源系统结构与用户需求分析入手,研究了地表水和地下水模型的耦合方法,构建了水资源目标规划模型,对独山子地区水资源进行了优化配置。研究表明:独山子地区水资源可以满足独山子区与灌区的现状需水要求。独山子区近期、中期、远期全部启动四个水源地供水仍不能满足需水要求,还需要外调水源补充解决,远期外调水已接近可调水资源量;为保证水源地有适量的河水入渗补给,限定了河道引水量,枯水年不能满足灌区的灌溉需水,平水年基本可以满足,丰水年完全能够满足。即使调水后,仍然要节水,提高灌溉效率。     

Evolution of a debris-rock slide causing a natural dam: the flash flood of Río Santa Cruz,Province of San Juan—November 12, 2005

Between 2001 and 2005, a large debris rock slide occurred on the western slope of the Cordillera de Santa Cruz in the southeast Andean corner of the Province of San Juan (31°40′ S–70°16′ W). The landslide material accumulated in a downstream gorge as a natural dam of the Santa Cruz river, forming a large-volume lake. In November 2005, probably as a result of the increasing pressure of the water volume, this natural dam breached off with a violent and unexpected flash flood. In addition to life-threatening instances lived by some people downstream, this flood caused great economic loss to main localities of the Department of Calingasta, as well as considerable damage to one of the most relevant projects of the Province, the Caracoles Hydropower Project dam on the San Juan river. Considering the high costs of any physical remediation for a natural dam located in this high, remote, and inaccessible mountain area with no reliable road access, the main protective measures left to be pondered are the installation of a flash-flood early-warning system connected to downstream localities, along with a program of hydrological monitoring at the dam-forming area and annual satellital monitoring to verify the evolution of accumulated mass movements.     

引大工程供水区水资源优化配置模型及方案研究

引大入秦工程是由大通河向甘肃中部兰州市永登县秦王川地区跨流域引水的以农业灌溉为主要目的大型调水工程。工程建成通水后,对改变当地农业生产条件和贫困面貌、安置贫困山区移民、促进秦王川地区的经济社会发展发挥了重要作用。但是,由于各种因素的综合影响,工程在设计效益的发挥等方面存在一些问题,集中表现在供水能力未能充分发挥、工程水资源配置没有实现最优化。在收集到翔实的第一手资料的基础上,将引大灌区和周边可能的供水范围作为一个统一的研究对象即引大工程供水区,根据供水区的供需水现状和用水发展趋势,采用水资源系统分析理论中的最优化技术,建立以经济效益、社会效益和环境效益最优为目标、以供需水量为约束条件的优化配置模型,通过求解模型,确定近期和远期供水区的水资源在各子区不同用水部门间的最优化配置方案,为富余水源寻找出路,这对最大限度地发挥工程效益,促进区域经济社会的可持续发展具有重要作用。