Narrow Results

Based on reasonable management of vegetation in arid area, we consider the effect of artificial irrigation and proposed a vegetation management model with seasonal rainfall and groundwater diffusion. In this work, we describe the relationship between vegetation and groundwater by impulsive differential equation. Sufficient conditions are derived to ensure global asymptotic stability of the vegetation-extinction boundary periodic solution. Sufficient conditions are also derived to examine the permanence of the investigated system. Besides, the correctness of our results is further verified through numerical simulations. These results show that artificial irrigation and groundwater diffusion have a positive effect on the survival of vegetation in arid area.

Despite their potential to conserve water, technological modernization investments that increase the efficiency of irrigation systems rarely result in water savings. On the contrary, they oftentimes increase overall water consumption. An important factor for this outcome is that farmers adapt their behavior to the new technological possibilities. If actual water savings are to be achieved, water conservation policies need to be tailored to the logic adapted by water users. In this study, we investigate the applicability and relevance of mental accounting in agricultural water use. In particular, we test whether farmers’ perceptions of water diverge conditional on whether it is supplied naturally or obtained from efficiency gains. We conduct a survey-based experiment among representatives of water user associations in Spain. According to the results, farmers tend to have a stronger sense of ownership over water that is obtained from efficiency increases than over water that originates from natural supply increases; however, they do not intend to use both “types” of water differently. Future policies could strongly benefit from targeting the sense of ownership of higher efficiency gains to achieve water savings. Furthermore, the responsibility of translating efficiency gains into water savings should rather be delegated to water user associations than to individual users.

When tendons, bones or joints are exposed in infected digits, functional and cosmetic sequelae are frequent. We propose continuous negative pressure therapy with irrigation (NPI) for an infected digit with an open wound. Continuous NPI was evaluated in vitro and subsequently applied to a clinical case. Acceptable functional and cosmetic results were obtained without any problems when continuous NPI was performed in the clinical case. Continuous NPI may be a useful alternative for treatment of an infected digit with an open wound.

We recently developed continuous negative pressure therapy with irrigation (NPI) and successfully applied it to an infected digit with a narrow wound. With this technique, however, the dressing circumferentially wraps the digit or hand, and the pressure that the digit or hand receives and the influence on peripheral circulation are unclear. In this report, we evaluated the external pressure that a digit and hand received during NPI in vitro. Under circumferential NPI dressing, the skin perfusion pressure (SPP) of the peripheral portion was measured. Pressure was maintained at 1.3 mm Hg, and suction pressure ranged from -50 to -200 mm Hg. The pressure that a digit or hand receives during NPI is much lower than that at which tissue may be damaged (40–50 mm Hg). The SPP of the peripheral portion was much higher than 40 mm Hg, which is the pressure at which wound healing may be predicted. In clinical cases, NPI has been useful for wound bed preparation.

Flexor sheath infection is a hand surgery emergency, and emergent washout is the accepted practice to prevent digital amputation. The authors describe surgical steps to optimize flexor sheath irrigation.

This paper has been motivated by the following ecological question: how influential is the water stress on plants production? The aim of this paper is to investigate the impact of water stress and irrigation on plants production. We propose a mathematical model for the dynamics growth of plants that takes into account the concentration of available water in the soil, the absorption of water by plants, water stress, the plants production and the plants compensation. We present the theoretical analysis of the model. More precisely, we show that the model is well-posed. We also compute trivial equilibria and derive a threshold parameter that determines the outcome of water stress within a plantation. Further, we perform a numerical simulation in the case of banana-plantain plant to support and valid theoretical results. We found that the Hopf bifurcation occurs for a specific value of the water absorption rate of unstressed plants. The impact of the water stress on the banana-plantain production is also numerically investigated. We found that the water stress can cause about $62.57\%$ tons of loss of banana-plantain production within a plantation with 1600 rejects initially planted. We also consider the irrigation as a control parameter of water stress. We found that the irrigation increases the stressed plant production to more than $60\%$ for $1600$ rejects initially planted. This suggests that climate change may play a detrimental role on banana-plantains production. We also investigate the role of the type of soil in banana-plantain production. Our finding suggests that the Fine Sandy Loam soil is more resilient to water stress than Silty Clay and Loamy soils.

Although there is now an extensive literature on the economic impacts of climate change on agriculture, no study has yet addressed the endogeneity of irrigation. This paper examines how climate affects the choice to irrigate and the conditional income earned by each farmer. The paper develops a selection model of irrigation choice and conditional income. Using data from farmers across eleven African countries, the paper demonstrates that the choice of irrigation is sensitive to both temperature and precipitation. Rainfed and irrigated farm income also both respond to climate but have different climate sensitivity. Impact models that fail to account for endogenous irrigation are biased.

Adaptation gaps arise when observed adaptation to climate change is slower than perceived adaptation potential. Two common explanations for adaptation gaps are (1) private parties failing to recognize that the climate is changing and (2) the cost of adaptation is higher than commonly believed. This paper shows how these two explanations are linked and that the likelihood and duration of adaptation gaps depend on whether climate change is characterized by stationary or non-stationary dynamics. Using an investment in water-saving irrigation in California’s Central Valley as an illustrative example, we find little evidence that failing to account for climate change would explain adaptation gaps. A more likely explanation for adaptation gaps is a failure to account for the adaptation option value that arises due to the possibility of maladaptation.

We estimate the effect of changes in water deliveries from large projects on agricultural production. We estimate a region-scale, multi-output production model of the San Joaquin Valley of California using observed historical data. The model incorporates seven crop outputs and the labor input as functions of project water supply, groundwater pumping price, other surface water sources, wages, and crop prices. We find that: (1) reduced irrigation water supply reduces the demand for farm labor and the production of some crops, (2) regional production mix tends to shift towards cotton when water supply is high and (3) some structural change has occurred over the course of our 22 year study period, with production of annual crops becoming more sensitive to changes in project water supply and labor becoming less sensitive to local surface water conditions.

Irrigators in the Murray–Darling Basin (MDB) of Australia face a salinity triple threat, namely: dryland salinity, surface-water, and groundwater salinity. Water trading has now been adopted to the point where it is a common adaptation tool used by the majority of irrigators in the Basin. This study uses a number of unique water market and spatial databases to investigate the association between the severity and extent of areas which suffer from salinity and permanent trade over time, holding other regional characteristics constant. It was found that larger volumes of permanent water were likely to be sold from areas suffering from higher dryland salinity. In addition, increases in the concentration of groundwater salinity was found to decrease volumes of surface-water entitlements sold, providing evidence that groundwater entitlements (where they are viable substitutes) have been increasingly used as substitutes for surface-water entitlements in recent years. Other key influences on water sales included water market prices and net rainfall.

Responsible application of finite resources to infinite needs means that proposals for irrigation improvement must be weighed and assessed. The assessment requires an understanding of the changes in flux, and the social, ecological and economic effect of such changes. This paper is focused on evaluation of changes in flux, not discounting the vital components of weighing the implications of the changes. A useful criterion for the assessment of the flux implications of improvements to irrigation efficiency is the net effect to basin water supplies. The flux assessment can be performed with four necessary and sufficient exercises: (1) Consider irrigator response to the change; (2) Close the water budget on all changes in flux resulting from the irrigator response; (3) Consider the economic rivalry effects of the changes in flux; (4) Quantify changes in supply to all affected participants. This paper focuses on the effect that these four factors have upon water flow, with the implicit assumption that flow impacts ecosystem services, private user benefits, and social equity. Knowledge of changes in flow is a necessary but not a sufficient input to the evaluation of these factors. Irrigator response can be assessed based on an assumption of rational profit-maximizing behavior, and on the legal and social bases of water use. Closing the water budget can be performed using methods found in an extensive literature describing evaporation, transpiration, irrigation requirements, irrigation efficiency, and the various fates of the non-consumed fraction of field-applied irrigation water. The physical effects of irrigation improvements can be further partitioned using the concepts of economic rivalry. The framework presented allows policy makers to evaluate the effects that improvements will have not only upon the improved water use and the new use to which “saved” water will be devoted, but also to the secondary effects and beyond, upon human uses or ecosystem services that currently rely upon the “waste” stream resulting from nominally inefficient application and use. While it is acknowledged that evaluation of ecosystem services requires greater knowledge of ecosystem functions than is available in many basins, at least this framework calls attention to the services and provides a quantification of the flux of water delivered to them.

Economic analyses of regional irrigated agricultural production typically make little distinction between perennial and annual crops despite the distinctive characteristics of perennials. Such factors include high planting costs, lags in production, long lifespan, and potentially long-lasting impacts of input use and weather shocks. This study establishes a fully dynamic model of irrigated perennial crop production in a regional context where annuals are also grown. Perennial crop area is modeled as a vintage capital stock with age-dependent yields. The model is applied to the Riverland region of South Australia to examine the possible effects of both temporary and permanent changes in water supplies and the establishment of water prices, which is then used to estimate agricultural water demand. The model demonstrates that annuals are fallowed during drought so that perennial crops may be preserved and how, due to the fixed costs of re-planting perennials, annual crops are used to smooth profits while recovering from a severe shock. In all scenarios, a very slow rate of convergence to the steady state is found, highlighting the need for models that capture the transitional dynamics of agricultural land use in areas with significant perennial production.

This paper employs laboratory and framed field experiments to investigate factors influencing the behavior of irrigation users, with an emphasis on the effects of exogenously and endogenously designed allocation rules. The experiments were conducted with 36 groups of farmers and students from China, India and Vietnam. The results show that physically asymmetric access to water as a resource creates an asymmetric distribution of investments, harvests and revenues that favors upstream users. Exogenously designed allocation rules appear able to equalize the distribution of revenue between upstream and downstream users, but are also likely to reduce the volume of investment and generated revenue. Meanwhile, communication between irrigation users with the possibility of endogenously designed rules appears to have a stronger equalizing effect on asymmetric resource access but also increases overall investment, which then increases water availability in a hypothetical irrigation channel. This suggests that promoting participation of irrigation users in designing rules for water distribution, water use monitoring and sanctioning might improve the performance of irrigation systems.

Generally, public investments in irrigation projects fail to deliver the desired outcomes largely due to inefficient management and use of the assets by the local level institutions. Against this backdrop, the present paper attempts to understand how the Pani Panchayats have performed in sustainable management and use of minor irrigation structures in the Indian state of Odisha. Using primary data and information collected from selected state-funded minor irrigation projects implemented in Cuttack district of the state, the paper finds that the Pani Panchayats, being backed by The Orissa Pani Panchayat Act (2002) and following a democratic decision making process, have been successful in managing the irrigation projects efficiently, especially in respect of pricing and distribution of irrigation water, maintenance of the systems, and their expansion, leading to socially inclusive and sustainable agricultural intensification in the area.

We used a participatory foresight method for assessing if, and how, groundwater markets could be incorporated into local groundwater management policies. We propose an institutional setup adapted to the French water policy context, with a cap and trade scenario introducing groundwater markets in the agricultural sector between now and the 2035 horizon. Considering the local hydrogeological characteristics, we applied this method to five French groundwater basins, and then analyzed the public perception of our scenario by organizing 16 half-day workshops, involving a total of 44 institutional stakeholders and 80 farmers. Overall, almost half of the participants were opposed to the introduction of groundwater markets for various ethical, economic and technical reasons. Many of the preconditions for water trading are still far from being met, and major social and economic risks are anticipated. However, our results also suggest that there might be scope for developing groundwater markets compatible with French water policy at a local scale; the preconditions for this are that specific local hydrogeological and agricultural situations are taken into account, and that a participatory process is developed, involving institutional stakeholders and farmers.

Though water scarcity threats are increasing in severity across many regions of the world, allocation often remains inefficient — as in Jordan, the site of this study. One commonly discussed solution for increasing resource availability in water-scarce regions is the use of recycled wastewater for irrigation. Yet, despite significant potential benefits, an oft-cited concern with wastewater reuse is its potential impact on water quality. This paper examines the impact of this solution by exploiting a natural experiment arising from complementary infrastructure investments that introduced recycled wastewater to a new region of the Jordan Valley. We study farmer preferences for wastewater reuse, as well as farm adaptation and profitability. We find no evidence of negative impacts on farm revenues or costs over the short term, and observe signs of adaptation via the shifting of production toward less-salinity sensitive crops. Contingent valuation measures of the willingness to pay for reliable recycled water supply across newly treated and comparison areas indicate resistance to the expanded reuse of wastewater, however, which suggests that farmers may believe that this shift will entail more substantial long-term costs. Furthermore, the stated willingness to pay and short-term marginal productivity of water estimates appear unrelated. These results suggest the need for caution in interpreting short-term adaptation and preference responses to policies that substantially alter irrigation choices and behaviors, and point to the need for longer-term studies of wastewater reuse.

Policymakers in Sub-Saharan Africa have placed considerable emphasis on expanding irrigated agriculture. This is in response to the subcontinent’s growing population pressure, coupled with production risks associated with declining and variable rainfall. Irrigation is viewed as an important strategy to improve food security and protect rural livelihoods, with small-scale irrigation identified as the preferred strategy. And yet, adoption of irrigation has been slow, and irrigation investments are often underutilized. Expanding irrigated agriculture through increases in cultivated area alone will not be sufficient for greater food security; land and water productivity of irrigated agriculture needs to be increased, and this may in fact help accelerate the adoption of irrigation. Shared irrigation investments among small farmers are going to be challenging to sustain as smallholder households diversify their livelihoods, and do not cultivate field crops every season. For individual irrigation technologies, many barriers exist in their adoption, especially the risks and ambiguities such as pestilence and borehole installation failures; and governments will have to invest significantly more than they currently do in research and extension efforts to ease these barriers. Finally, the expansion of irrigation, especially individual irrigation, will likely create environmental challenges such as aquifer depletion, water pollution, and soil degradation, which governments would also have to manage by coordinating the actions of individual smallholders. This paper identifies the kind of institutional infrastructure and policy support that African agriculture will need to have in place to expand irrigation beyond its current status.

In a canonical model of collective action, individual contribution to collective action is negatively correlated with group size. Yet, empirical evidence on the group size effect has been mixed, partly due to heterogeneities in group activities. In this paper, we first construct a simple model of collective action with the free rider problem, altruism, public goods, and positive externalities of social networks. We then empirically test the theoretical implications of the group size effect on individual contribution to four different types of collective action, i.e., monetary or nonmonetary contribution to directly or indirectly productive activities. To achieve this, we collect and employ artefactual field experimental data such as public goods and dictator games conducted in southern Sri Lanka under a natural experimental situation where the majority of farmers were relocated to randomly selected communities based on the government lottery. This unique situation enables us to identify the causal effects of community size on collective action. We find that the levels of collective action can be explained by the social preferences of farmers. We also show evidence of free riding by self-interested households with no landholdings. The pattern of collective action, however, differs significantly by mode of activity—collective action that is directly rather than indirectly related to production is less likely to suffer from the free rider problem. Also, monetary contribution is less likely to cause free riding than nonmonetary labor contribution. Unlike labor contributions, monetary contributions involve collection of fees which can be easily tracked and verified, possibly leading to better enforcement of collective action.

An essential topic for policymakers is the environmental and socioeconomic impact of food supply chains. The world population is growing; consequently, food consumption is expected to increase, and Brazil is one of the important countries in global food production with the potential to supply food to meet this higher food demand in the world. Considering this context, the aim of this chapter is to propose a double-frontier data envelopment analysis (DEA) model to benchmark Brazilian regions for the sustainable expansion of food production. Thus, for this purpose, a slack-based measure (SBM) DEA model combined with the composite index double-frontier method is developed for efficiency analysis of the Brazilian regions, deemed decision-making units (DMUs), based on satellite data from the Brazilian Annual Land Use and Land Cover Mapping Project (MAPBIOMAS) and the Greenhouse Gas Emission and Removal Estimating System (SEEG). The data are split into negative factors (NFs), undesirable outputs (UOs), or inputs (e.g., irrigation and CO₂ equivalent emissions related to the agricultural sector), and positive factors (PFs) or outputs (e.g., food productivity or pasture area). This chapter uses averaged data from 2017 to 2021 for 14 of the 26 (plus the Federal District) Brazilian states. As for the results, Santa Catarina is in the first position of the ranking (first recommendation for expansion of agricultural production). In terms of regions, the northeast has two states in the efficient frontier and none in the inverted frontier, while the southeast has none in the efficient frontier and two in the inverted frontier. The other regions have states in both frontiers. These results would help provide policymakers with strategies for future investment to expand food production. For future research, it is suggested to apply the proposed model using data from other countries and develop stochastic DEA models, besides investigating the efficiency of future scenarios.

This chapter sets the stage for most of the concepts and jargon a “water person” uses. It considers global water issues, sectoral use patterns, and other water-related concepts such as water scarcity. The chapter will likewise demonstrate the link between a basin's water situation and the potential conflict that can arise between the riparians. You will also be introduced to concepts relevant to international water agreements. Finally, you will note the distribution of international river basins and the nature of various conflicts over water.