Dynamics in the governance of collective irrigation systems: Evidence from field experiments in Nicaragua.

In this paper, we investigate the real demand for climate protection when the purely individual perspective of existing revealed preference studies is relaxed. This is achieved in two treatments; first, we determine the information subjects receive about the demand revealed by other subjects in a similar decision making situation, second, collective action is implemented whereby all subjects are required to purchase the group?s median quantity at a given price. Participants in the experiment were offered the opportunity to contribute to climate protection by purchasing European Union Allowances. Allowances purchased were withdrawn from the European Emissions Trading Scheme. In our experiment, information about other subjects? behaviour has no treatment effect on the demand for climate protection. Under collective action however, the probability of purchasing allowances is higher compared to the reference treatment situation, an individual contribution mechanism. Furthermore, we observe a strong correlation between subjects? demand and their expectations about other participants? behaviour. When collective action is not available, subjects? e xpectations are consistent with free rider behaviour.

Dynamics in the governance of collective irrigation systems: Evidence from field experiments in Nicaragua.

The objective of this study is to analyze the common pool resource appropriation and public good provisiondecisions in a dynamic setting, testing the differences in behavior and performance between lab and field subjects. We performeda total of 45 games in Nicaragua, including 88 villagers in rural communities and 92 undergraduate students. In order to analyze sequential decision making, we introduce a dynamic and asymmetric irrigation game that combines the typical social dilemmas associated to irrigation systems management.In addition, in 9 out of 22 villagers’ groups, we implemented a treatment that included the disclosure of subjects’ appropriation of the common pool resource. The results reveal that the provision of individuals’ appropriation level results in higher appropriation in subsequent rounds. In addition, the results show that non-treated villagers provide more public good than treated villagers but if compared with students the differences are not significant. The results also suggest that appropriation levels are below the Nash prediction of full appropriation, but above the social efficient level. This results in an efficiency loss in the game that can be explained to a large extent by individual decisions on appropriation and public good contribution and by group appropriation behavior.

Integrated assessment of policy interventions for promoting sustainable irrigation in semi-arid environments: A hydro-economic modeling approach

Sustaining irrigated agriculture to meet food production needs while maintaining aquatic ecosystems is at the heart of many policy debates in various parts of the world, especially in arid and semi-arid areas. Researchers and practitioners are increasingly calling for integrated approaches, and policy-makers are progressively supporting the inclusion of ecological and social aspects in water management programs. This paper contributes to this policy debate by providing an integrated economic-hydrologic modeling framework that captures the socio-economic and environmental effects of various policy initiatives and climate variability. This modeling integration includes a risk-based economic optimization model and a hydrologic water management simulation model that have been specified for the Middle Guadiana basin, a vulnerable drought-prone agro-ecological area with highly regulated river systems in southwest Spain. Namely, two key water policy interventions were investigated: the implementation of minimum environmental flows (supported by the European Water Framework Directive, EU WFD), and a reduction in the legal amount of water delivered for irrigation (planned measure included in the new Guadiana River Basin Management Plan, GRBMP, still under discussion). Results indicate that current patterns of excessive water use for irrigation in the basin may put environmental flow demands at risk, jeopardizing the WFD s goal of restoring the ?good ecological status? of water bodies by 2015. Conflicts between environmental and agricultural water uses will be stressed during prolonged dry episodes, and particularly in summer low-flow periods, when there is an important increase of crop irrigation water requirements. Securing minimum stream flows would entail a substantial reduction in irrigation water use for rice cultivation, which might affect the profitability and economic viability of small rice-growing farms located upstream in the river. The new GRBMP could contribute to balance competing water demands in the basin and to increase economic water productivity, but might not be sufficient to ensure the provision of environmental flows as required by the WFD. A thoroughly revision of the basin s water use concession system for irrigation seems to be needed in order to bring the GRBMP in line with the WFD objectives. Furthermore, the study illustrates that social, economic, institutional, and technological factors, in addition to bio-physical conditions, are important issues to be considered for designing and developing water management strategies. The research initiative presented in this paper demonstrates that hydro-economic models can explicitly integrate all these issues, constituting a valuable tool that could assist policy makers for implementing sustainable irrigation policies.

Effects of irrigation and time of application on the yield and quality of cv. Cabernet sauvignon in a warm climate

Mediterranean climate is characterized by hot summer, high evapotranspiration rates, and scarce precipitations (400 mm per year) during grapevine cycle. These extremely dry conditions affect vineyard productivity and sustainability. Supplementary irrigation is a needed practice in order to maintain yield and quality. Almost all Spanish grape growing regions are characterized by these within this context, especially in the center region, where this study was performed. The main objective of this work was to study the influence of irrigation on yield and quality. For this aim, we applied different levels of irrigation (mm of water applied) during different stages of growth and berry maturity. Four experimental treatments were applied considering the amount of water and the moment of the application: T1: Water irrigation (420 mm) applied from bloom to maturity. T2: Corresponded to the traditional irrigation scheduling, from preveraison to maturity (154 mm). T3: Water irrigation from bloom to preveraison, and water deficit from veraison to maturity (312 mm). T4: Irrigation applied from preveraison to maturity (230 mm) Experimental vineyard, cv. Cabernet Sauvignon, was located in a commercial vineyard (Bodegas Licinia S.L.) in the hot region of Morata de Tajuña (Madrid). The trial was performed during 2010 and 2011 seasons. Our results showed that yield increased from 2010 to 2011 in the treatments with a higher amount of water appli ed, T1 and T3 (24 and 10 % of yield increase respectively). This was mainly due to an increase in bud fertility (nº of bunches per shoot). Furthermore, sugar content was higher in T3 (27.3 ºBrix), followed by T2 (27 ºBrix). By contrast, T4 (irrigation from veraison) presented the lowest solid soluble concentration and the highest acidity. These results suggest that grapevine has an intrinsic capacity to adapt to its environment. However, this adaptation capacity should be evaluated considering the sensibility of quality parameters during the maturity period (acidity, pH, aroma, color...) and its impact on yield. Here, we demonstrated that a higher amount of water irrigation applied was no linked to a negative effect on quality.

Management of irrigation frequency and nitrogen fertilization to mitigate GHG and NO emissions from drip-fertigated crops

Drip irrigation combined with split application of fertilizer nitrogen (N) dissolved in the irrigation water (i.e. drip fertigation) is commonly considered best management practice for water and nutrient efficiency. As a consequence, its use is becoming widespread. Some of the main factors (water-filled pore space, NH4+ and NO3−) regulating the emissions of greenhouse gases (i.e. N2O, CO2 and CH4) and NO from agroecosystems can easily be manipulated by drip fertigation without yield penalties. In this study, we tested management options to reduce these emissions in a field experiment with a melon (Cucumis melo L.) crop. Treatments included drip irrigation frequency (weekly/daily) and type of N fertilizer (urea/calcium nitrate) applied by fertigation. Crop yield, environmental parameters, soil mineral N concentrations and fluxes of N2O, NO, CH4 and CO2 were measured during 85 days. Fertigation with urea instead of calcium nitrate increased N2O and NO emissions by a factor of 2.4 and 2.9, respectively (P < 0.005). Daily irrigation reduced NO emissions by 42% (P < 0.005) but increased CO2 emissions by 21% (P < 0.05) compared with weekly irrigation. We found no relation between irrigation frequency and N2O emissions. Based on yield-scaled Global Warming Potential as well as NO cumulative emissions, we conclude that weekly fertigation with a NO3−-based fertilizer is the best option to combine agronomic productivity with environmental sustainability. Our study shows that adequate management of drip fertigation, while contributing to the attainment of water and food security, may provide an opportunity for climate change mitigation.

Biomass and essential oil yields of cornmint (Mentha arvensis L.) grown in the irrigation area of Río Dulce, Santiago del Estero, Argentina.

The aim of this study is to determine the yield and composition of the essential oil of cornmint (Mentha arvensis L.) grown in the irrigation area of Santiago del Estero, Argentina. Field tests were carried out under irrigation conditions, harvesting when 70% flowering was reached (in the summer and at the end of the winter seasons). Essential oil yields were 2% in the first cut and 1.6% in the second cut, respectively, the major constituents of the essential oil being menthol, menthone, isomenthone and menthofuran. In both cases, a high concentration of menthol was obtained, although during the winter the content decreased, increasing the concentration of menthofuran. It is concluded that during the summer a higher yield and better quality of essential oil are produced.

The optimal allocation rule and the water market as the most effective tools of managing water shortage in an irrigation district

The conference program will cover all areas of environmental and resource economics, ranging from topics prevailing in the general debate, such as climate change, energy sources, water management and ecosystem services evaluation, to more specialized subjects such as biodiversity conservation or persistent organic pollutants. The congress will be held on the Faculty of Economics of the University of Girona, located in Montilivi, a city quarter situated just few minutes from the city center, conveniently connected by bus lines L8 and L11.

Self-regulation of discharge in non-compensating subsurface drip irrigation emitters

Se muestra los resultados de un studio con modelos de goteros enterrados donde se observa un efecto de autoreegulación del efecto de sobrepresión del agua en el suelo.

Quality attributes of pistachio nuts as affected by rootstocks and deficit irrigation

BACKGROUND: In this work, the influence of two regulated deficit irrigation (RDI) treatments and three different rootstocks on the quality of pistachios was evaluated by analyzing different parameters: morphological analysis, physicochemical analysis and sensory analysis. RESULTS: The results obtained in terms of the choice of rootstock revealed that Pistacia atlantica had increased production yields, nut weight, mineral content, higher intensities of characteristic sensory attributes and a higher degree of consumer satisfaction, than the other rootstocks studied. Moreover, the results established that the application of RDI on pistachio cultivation had no significant influence on production yield, weight, size, colour, water activity or mineral composition. Furthermore, T1 treatment (stem water potential?of characteristic sensory attributes and a greater level of satisfaction among international consumers. CONCLUSION: These results confirm that the application of deficit irrigation (T1) contributes to an increase in overall product quality. Furthermore, Pistacia atlantica rootstock provided better yield and quality than the other rootstocks studied. © 2014 Society of Chemical Industry

Optimization of water procurement decisions in an irrigation district: the role of option contracts

Water supply instability is one of the main risks faced by irrigation districts and farmers. Water procurement decision optimisation is essential in order to increase supply reliability and reduce costs. Water markets, such as spot purchases or water supply option contracts, can make this decision process more flexible. We analyse the potential interest in an option contract for an irrigation district that has access to several water sources. We apply a stochastic recursive mathematical programming model to simulate the water procurement decisions of an irrigation district?s board operating in a context of water supply uncertainty in south-eastern Spain. We analyse what role different option contracts could play in securing its water supply. Results suggest that the irrigation district would be willing to accept the proposed option contract in most cases subject to realistic values of the option contract financial terms. Of nine different water sources, desalination and the option contract are the main substitutes, where the use of either depends on the contract parameters. The contract premium and optioned volume are the variables that have a greater impact on the irrigation district?s decisions. Key words: Segura Basin, stochastic recursive programming, water markets, water supply option contract, water supply risk.

Influence of characteristics of irrigation channels on the breeding bird community of a wetland zone in southeast of Spain

The “El Hondo Nature Park” is mainly composed of a series of irrigation channels and water reservoirs, subjected to various regimes of management as well as reed and vegetation control, thus creating a great variety of habitats and situations. To determine the influence of these habitats and management regimes on the local bird community, a set of characteristics of these channels and their surrounding area were analysed with a Correspondence Analysis (CA). The degree of reed development in channels and the presence in the surroundings of orchards and other reed formations were the most decisive factors to explain the probability of occurrence of reed birds and waterbirds, as well as bird species richness and abundance. Other bird species were not directly influenced by channel variables, but only by those of surrounding land uses.

A general system of nature, through the three grand kingdoms of animals, vegetables, and minerals, systematically divided into their several classes, orders, genera, species, and varieties, with their habitations, manners, economy, structure and peculiarities. /

v. 7 (1806)