The Lower Rio Grande Valley: a case study of a water market area

The Lower Rio Grande Valley is a sub-tropical area with a productive irrigated agriculture, but with an over-committed single water resource. It is experiencing a rapidly growing population that is placing increasing pressure on the water resource. This, combined with expanding urban areas and land moving out of agriculture, has resulted in a vigorous water market, with transfers from agriculture to municipal uses. For the US portion of the valley, transfers from agriculture to municipalities are either short-term (usually 1 year) or permanent. Prices vary depending upon the location and timing, and result from negotiations between the parties. Over time, and not without difficulty, the water market has been facilitated by appropriate enabling legislation, water rights that have been validated judicially, and an efficient transfer mechanism that has a minimum of transaction cost. Government involvement is primarily for protection of the public, and to facilitate the transfer process.

Water transfer from agriculture to urban uses: lessons learned, with policy considerations

This paper sets forth the accomplishments to date of the international collaborative study program on efficient and equitable transfer of water from agriculture to other uses. The research consists of several components. First a bibliographical review was prepared of literature available on the practice of inter-sector water transfer. Second, nine case studies have been prepared that illustrate inter-sector water transfer under a variety of physical and economic and political environments. Third, a framework has been developed for characterizing and comparing water transfer options and compensation among case studies. We discuss the pricing of irrigation water in determining compensation. We develop a decision tree that traces the paths to the various sector water transfer options. Finally, we discuss water transfer policy options with specific reference to Taiwan, though they have more general relevance. Three options are identified which reflect different objectives for government intervention.     

A viewpoint to apply water pricing to the Asian humid tropics

The OECD has introduced a water pricing mechanism and listed eight categories gleaned from experience in OECD countries. However, in the Asian humid tropics, it is too early to apply water pricing because there is seldom a concept of water right, or practical organization of water management. In almost all irrigation projects in Japan, area charge has been applied, and collected fees have recovered entire operation and maintenance costs. Although effective volumetric charge is employed in several regions in Japan, most farmers pay area-based annual charges at several times of the year via Land Improvement Districts. In the Asian humid tropics, it is important to facilitate the establishment of sound management organizations of irrigation water before introducing a strict water pricing mechanism to levy the charge.     

Appropriation of Río San Juan water by Monterrey City, Mexico: implications for agriculture and basin water sharing

Monterrey metropolitan area’s growth has resulted in water transfers from the Río San Juan basin with significant impacts for downstream water users, especially farmers in the Bajo Río San Juan (BRSJ) irrigation district. El Cuchillo dam is the centerpiece of the basin’s water management infrastructure and has become the flashpoint of a multi-faceted water dispute between the states of Nuevo León and Tamaulipas as well as between urban and agricultural water interests in the basin. Subsequent to El Cuchillo’s implementation in 1994, the BRSJ irrigation district has been modifying its irrigation operations to adjust to the new water availability scenario. Compensation arrangements for farmers have been established, including crop loss payments on the order of US$ 100 per hectare un-irrigable due to the diversion of water to Monterrey plus 60% of the water diverted to be returned to farmers as treated effluent via the Ayancual Creek and Pesquería River, a process with its own water competition and environmental implications. The Mexican irrigation sector will continue to face intense competition for water given: (a) low water productivity in agriculture leading decision-makers to allocate water to higher productivity uses particularly in cities, (b) priority accorded to the domestic use component of municipal water supply, and in the BRSJ case, (c) Mexico’s national interests in meeting its water sharing obligations with the United States.     

Transferring water from irrigation to higher valued uses: a case study of the Zhanghe irrigation system in China

The Zhanghe irrigation system (ZIS) is located in the Yangtze River Basin approximately 200 km west of Wuhan in Hubei Province. The reservoir was designed for multiple uses—irrigation, flood control, domestic water supply, industrial use, aquaculture, and hydropower. Over a period of more than 30 years a steadily increasing amount of water has been transferred from irrigation to other uses. Activities on the part of government, irrigation system managers, and farmers made this transfer possible with only modest decline in rice production. Most important factor was the steady increase in rice yields. The water pricing system provided an incentive for ZIS to reduce irrigation releases. With the steady decline in releases, farmers were forced to find ways to save water. Farmers improved existing ponds and built new ones to store water (improved infrastructure). Access to pond water on demand facilitated the adoption of alternate wetting and drying (technology) particularly in dry years. The establishment of volumetric pricing (price policy) and water user associations (institutions) may also have provided incentives for adoption of AWD, but more research is needed to establish their impact. These activities taken together can be seen as potentially complementary measures. Farmers received no direct compensation for the transfer of water, but recently farm taxes have been reduced or altogether abolished. Further reduction in water releases from the ZIS reservoir could adversely affect rice production in normal or dry years.     

The impact of the locust control insecticide fipronil on termites and ants in two contrasting habitats in northern Australia

Termites and ants are key ecosystem engineers and nutrient re-cyclers. Extensive spraying of insecticides presents a hazard to these insects. Using a control-treatment paired design comprising 3 replicate pairs of plots per soil type, we quantified the impact of fipronil on termite consumption of cardboard and wood baits, termite repair of deliberately damaged mounds as well as ant community composition and abundance in two different habitats (black vertisol and red kandosol soil) when applied aerially at a dose rate recommended for locust control in Australia. The study was conducted from 2006 to 2008. The diversity of termites and ants was higher and side-effects were more pronounced on kandosol than on vertisol soil. Overall termite consumption of cardboard baits was significantly greater in unsprayed than in sprayed plots while losses were significantly greater in only one (vertisol) or two (kandosol) sprayed plots, respectively, compared to paired unsprayed plots. In the first year, termite consumption of wood baits was generally significantly greater on unsprayed than on sprayed kandosol while only marginally significant on unsprayed vertisol. Again, losses were significantly greater in one (vertisol) and two (kandosol) sprayed plots, respectively, compared to paired unsprayed plots. Overall termite consumption of wood baits was similar among plots in the second year post-spray although consumption remained significantly depressed in one pair of sprayed plots in each habitat. The capacity of the mound-building termite, Drepanotermes rubriceps (Froggatt) unique to kandosol, to repair damaged mounds was significantly reduced by fipronil. Furthermore, colonies of Iridomyrmex greensladei Shattuck, an ant species associated with mounds of D. rubriceps, were not re-located five months post-spray. Ant communities were also adversely affected. On vertisol, species richness and relative abundance were similar among treatments, but significantly fewer species were caught in one individual sprayed plot. In contrast on kandosol, species richness and relative abundance were significantly reduced by fipronil. A drop in species richness was observed in all and a drop in relative abundance in two sprayed plots. On vertisol, abundances of two species were significantly lower in sprayed than in paired unsprayed plots. Likewise on kandosol, abundances of five species were significantly reduced in sprayed plots, and one species was not caught at all. The weight of evidence of our findings indicate that fipronil, even at a low rate, will have substantial adverse impacts on the diversity and activity of termites and ants, especially if applied within one to two years of earlier applications.     

Water transfer from agriculture to urban domestic users: a case study of the Tone River Basin, Japan

Agricultural water reorganization measures (AWRM) is an approach that has been adopted in Japan for more than 30 years to capture excess water from agriculture for other uses by relying on the modernization of existing irrigation infrastructures. This paper reviews the history and processes of four such permanent water transfers by AWRM in the Tone River Basin, specifically those conducted in the Saitama Prefecture, Japan. The benefit of AWRM for the agricultural sector is the lowering of rehabilitation costs by sharing part of it with the city sector. AWRM does not require saving water at the on-farm level. Instead, the labor requirement of farmers is reduced by the rehabilitation and installation of pipelines. The benefit to the city is the lower cost, when compared with costs for the development of new water resources, and the relatively short duration of the project, which are important factors in an environment of the rapid increase in domestic water demand.

Cost sharing and sustainability of Pongsak Muang Fai irrigation system

The centuries-old, self-organizing Muang Fai community irrigation institution in northern Thailand has high potential in illustrating exemplary practices in irrigation cost sharing. This paper examines the cost sharing structure of the Pongsak Muang Fai Irrigation System in Mae Hong Son Province and its relationship with the system water management and sustainability. Results show that this primitive and high cost system accepts costs of the weir, the entire length of main ditch, not only the individually related ditch sections, and the management as common costs that should be equally shared so that it can gather sizeable membership to support the system. The capacity of this small scale run-of-the-river irrigation system with no river flow limitation is a simple summation of all determined farm intake capacities. The maintenance cost of the system every year depends on how much water should be diverted and conveyed, hence the use of “relative” scale of each farm intake capacity as the basis for sharing cost in the wet season paddy farming. Such structure is directly related to the water management under which every intake shall be served with continuous supply without permitting mid-canal water check-up and the members prefer to take collective action to keep enough water supply without leaving any room for suspicion of unfair water distribution. The direct relationship makes the members understand the purpose of payment and be willing to share the costs which are transparently estimated in easily understood terms and clearly de-aggregated into categories.     

三个小麦-大麦2H二体异代换系的细胞学及补偿能力研究

为了给小麦-大麦异代换系的进一步利用奠定基础,观察分析了三个小麦-大麦2H二体异代换系2H(A)、2H(B)和2H(D)花粉母细胞减数分裂中期的染色体构型。结果表明,三个代换系的染色体构型均为2n=21Ⅱ,含有一对大麦Betzes 2H染色体,在细胞学上是稳定的;三个代换系具有21Ⅱ的频率依次为92.56%、94.12% 和95.41%。同时,在花粉母细胞减数分裂后期观察到了落后染色体、染色体桥及不同步分裂等现象,其出现的频率为2H(A)大于2H(B)和2H(D)。从各代换系的生活力、不育率和其他农艺性状看,大麦2H染色体导入小麦背景后,对小麦2B、2D的补偿能力好于2A。     

玉米主产区利益流失与补偿机制研究

在简述我国玉米主产区利益流失根源的基础上,系统分析以吉林省为代表的玉米主产区在商品粮生产经营过程中存在的利益流失问题,探讨显性利益流失和隐性利益流失的形态,并以吉林省为例测算显性利益流失的数量,在此基础上构建玉米主产区利益补偿机制,明确玉米主产区利益补偿的主体和受体、补偿标准以及现金补偿与政策性补偿的运行机制及实施问题。     

不同基因型玉米自交系苗期干旱-复水的生理响应机制

采用称重控水法模拟干旱胁迫,设对照和胁迫两个处理,在3叶期对24个玉米自交系叶片相对含水量(RWC)、游离脯氨酸(Pro)等生理指标进行测定,研究玉米的抗旱机理及复水补偿效应机制。结果表明,干旱胁迫下玉米叶片相对含水量、叶绿素荧光参数(F_v/F_m)和叶绿素含量(Chl)与对照相比显著下降,游离脯氨酸(Pro)、超氧化物歧化酶(SOD)和氧化物酶(POD)明显上升,复水后不同基因型自交系各生理指标表现出不同程度的补偿效应。利用隶属函数法将D17982、郑H71、PH4CV、昌7-2和L269等14份自交系归为抗旱性较强的自交系,PH4CV、HCL645、D17982、郑7314、郑H71和郑9712这6份自交系归为复水恢复能力强的自交系。     

雨养和灌溉条件下施氮量对小麦干物质积累和产量的影响

为给冀东地区小麦高产栽培提供技术参考,以高蛋白质品种京冬8号和低蛋白质品种宝麦38为材料,设置0、120、240和360kg·hm-2三个施氮水平,研究了在灌溉和雨养条件下氮素营养对冬小麦干物质积累和产量形成的调控效应。结果表明,适量施氮提高了小麦干物质积累量、结实小穗数和穗粒数,促进了叶片、茎和鞘的花前贮存干物质在花后向籽粒中的转移,但过量施氮则抑制灌溉条件下营养器官花前贮存干物质在花后向籽粒的转移。施氮量对千粒重的影响因基因型和土壤水分状况不同而差异。随施氮量的增加,在雨养和灌溉条件下京冬8号千粒重分别呈降低和增加趋势,宝麦38千粒重均呈下降趋势。适当施氮可促进分蘖和分蘖成穗。与雨养栽培相比,灌溉可促进小麦干物质积累,增加穗数和延长灌浆时间,提高籽粒产量。随着施氮量的增加,两品种的氮肥生产效率和氮肥农学效率均降低。宝麦38和京冬8号籽粒产量达到最高的施氮量在雨养条件下均为120kg·hm-2,在灌溉条件下分别为120和240kg·hm-2。从产量和氮肥利用效率综合来看,宝麦38的适宜施氮量为120kg·hm-2,京冬8号的适宜施氮量为120~240kg·hm-2。     

基于GIS的海南岛森林生态系统服务功能价值评估

对海南岛森林涵养水源、保育土壤、固碳释氧、积累营养物质、净化大气环境、生物多样性保护、森林防护和森林游憩8个方面14个指标进行生态系统服务功能价值评估。结果表明：海南岛8项生态服务功能总价值量2 528.29亿元/年,功能价值贡献大小依次为：涵养水源（47.52％）＞净化环境(12.35％)＞固碳释氧（11.68％）＞生物多样性保护（10.31％）＞固土保肥(6.65％)＞森林防护(6.16％)＞森林游憩(4.42％)＞积累营养物质(0.91％),根据不同森林类型的生态服务功能价值量分析,原始林（28.34％）＞次生林（26.96％）＞橡胶林（24.42％）＞用材林（14.02％）＞防护林（3.24％）＞经济林（2.29％）＞灌木林（0.43％）＞红树林（0.29％）。     

Increased yield stability of field-grown winter barley (Hordeum vulgare L.) varietal mixtures through ecological processes

Crop variety mixtures have the potential to increase yield stability in highly variable and unpredictable environments, yet knowledge of the specific mechanisms underlying enhanced yield stability has been limited. Ecological processes in genetically diverse crops were investigated by conducting field trials with winter barley varieties (Hordeum vulgare), grown as monocultures or as three-way mixtures in fungicide treated and untreated plots at three sites. Mixtures achieved yields comparable to the best performing monocultures whilst enhancing yield stability despite being subject to multiple predicted and unpredicted abiotic and biotic stresses including brown rust (Puccinia hordei) and lodging. There was compensation through competitive release because the most competitive variety overyielded in mixtures thereby compensating for less competitive varieties. Facilitation was also identified as an important ecological process within mixtures by reducing lodging. This study indicates that crop varietal mixtures have the capacity to stabilise productivity even when environmental conditions and stresses are not predicted in advance. Varietal mixtures provide a means of increasing crop genetic diversity without the need for extensive breeding efforts. They may confer enhanced resilience to environmental stresses and thus be a desirable component of future cropping systems for sustainable arable farming.     

玉米冠层结构的自动调节与补偿机制研究

在玉米不同种植密度群体中初步研究了玉米群体的自动调节与补偿。结果表明,玉米群体在一定的密度范围内具有较强的自动调节能力。群体在叶面积上的自动调节能力较弱,而在干物质生产上的自动调节能力则较强。群体的自动调节作用对生殖器官的影响大于对营养器官的影响。产量因素的自动调节作用是生长后期的产量因素补偿生长前期损失的产量因素。     

Chlorophyll meter-based nitrogen management of rice grown under alternate wetting and drying irrigation

Farmers have adopted alternate wetting and drying (AWD) irrigation to cope with water scarcity in rice production. This practice shifts rice land away from being continuously anaerobic to being partly aerobic, thus affecting nutrient availability to the rice plant, and requiring some adjustment in nutrient management. The use of a chlorophyll meter (also known as a SPAD meter) has been proven effective in increasing nitrogen-use efficiency (NUE) in continuously flooded (CF) rice, but its use has not been investigated under AWD irrigation. This study aimed at testing the hypotheses that (i) SPAD-based N management can be applied to AWD in the same way it is used in CF rice, and (ii) combining chlorophyll meter-based nitrogen management and AWD can enhance NUE, save water, and maintain high rice yield. Experiments were conducted in a split-plot design with four replications in the 2004 and 2005 dry seasons (DS) at IRRI. The main plots were three water treatments: CF, AWD that involved irrigation application when the soil dried to soil water potential at 15-cm depth of −20 kPa (AWD₋₂₀) and −80 kPa (AWD₋₈₀) in 2004, and AWD₋₁₀ and AWD₋₅₀ were used in 2005. The subplots were five N management treatments: zero N (N₀), 180 kg N ha⁻¹ in four splits (N₁₈₀), and three SPAD-based N-management treatments in which N was applied when the SPAD reading of the youngest fully extended leaf was less than or equaled 35 (N_SPAD35), 38 (N_SPAD38), and 41 (N_SPAD41). In 2005, N_SPAD32 was tested instead of N_SPAD41. A good correlation between leaf N content per unit leaf area and the SPAD reading was observed for all water treatments, suggesting that the SPAD reading can be used to estimate leaf N of rice grown under AWD in a way similar to that under CF. SPAD readings and leaf color chart (LCC) values also showed a good correlation. There were no water × nitrogen interactive effects on rice yield, water input, water productivity, and N-use efficiency. Rice yield in AWD₋₁₀ was similar to those of CF; yields of other AWD treatments were significantly lower than those of CF. AWD₋₁₀ reduced irrigation water input by 20% and significantly increased water productivity compared with CF. The apparent nitrogen recovery and agronomic N-use efficiency (ANUE) of AWD₋₁₀ and AWD₋₂₀ were similar to those of CF. The ANUE of N_SPAD38 and N_SPAD35 was consistently higher than that of N₁₈₀ in all water treatments. N_SPAD38 consistently gave yield similar to that of N₁₈₀ in all water treatments, while yield of N_SPAD35 about 90% of that of CF. We conclude that a combination of AWD₋₁₀ and SPAD-based N management, using critical value 38, can save irrigation water and N fertilizer while maintaining high yield as in CF conditions with fixed time and rate of nitrogen application of 180 kg ha⁻¹. Treatments AWD₋₂₀ and N_SPAD35 may be accepted by farmers when water and N fertilizer are scarce and costly. The findings also suggested LCC can also be a practical tool for N-fertilizer management of rice grown under AWD, but this needs further field validation.     

The development and management policy of water resources in Taiwan

Taiwan is a small island located in monsoon Asia with an annual precipitation exceeding 2,500 mm, which is 2.6 times the world average. However, water available for each person in Taiwan is less than one seventh of the world average due to Taiwan's crowded population and river basin characteristics. Steep land slope and uneven time and space distribution of rainfall have caused water resources problems. Providing a pure and plentiful supply of water for the people challenges the Water Resources Agency in Taiwan. History is a powerful tool for portraying the future. This paper discusses major themes in the review of water resources development over the last centuries. The changes in social-economic development, water resources infrastructure and demands of water are central to the discussion, with an eye to the plentiful and sustainable implications of water resources management in Taiwan. The water policy in the twenty-first century is also outlined.Dr. Hwang is the Advice of the Council for Economic Planning and Development (CEPD), Ministry of Economic Affairs (MOEA), Taiwan, Chairman of the Water Resources Committee, Chinese Institute of Civil and Hydraulic Engineering, a board member of the International Commission on Irrigation and Drainage (ICID) Chinese Taipei Committee, former chairman of the Chinese Society of Agriculture Engineering (CSAE), former director of Water Resources Agency (WRA), former director of the Taiwan Provincial Water Conservancy Agency (TPWCA), and former director of the Taiwan Provincial Water Conservancy Bureau (TPWCB).     

兴义雪梨园生态系统平衡的调控

为综合运用自然气候、害虫天敌和人工干预技术措施调控兴义雪梨园生态系统的平衡,改变施农药防治害虫的传统方法,2001～2004年,在兴义雪梨园设点,调查园中邻耕区、更替区、辟荒区内年度虫种结构、主要害虫、害虫天敌世代生活史。结果表明,2001～2004年,兴义雪梨园产量逐年增加,无大小年现象;梨个体较整齐,外观品质好,内在品质好,无农药污染;梨园内害虫未暴发,梨园内生物种类和数量增多,兴义雪梨园生态系统基本平衡。