Estimating groundwater withdrawals in areas of intensive agricultural pumping in central Spain

Measuring groundwater extractions is central to adequate groundwater management in agricultural basins. Groundwater pumping records are often subject to considerable uncertainties, particularly in the case of arid and semiarid settings where irrigation is the most important water use. In most cases this is due to the difficulties involved in locating and monitoring all wells. We describe the estimation of groundwater pumping by coupling the water table fluctuation method with the groundwater balance equation. This is demonstrated through its application to the Mancha Occidental aquifer, Spain, an area subject to intensive pumping for irrigation since the early 1970s. A sensitivity analysis is conducted to evaluate the effect of relevant hydrogeological parameters, namely specific yield, as well as the most appropriate theoretical semivariogram, to calculate yearly storage variations within the system. Results are validated in the light of official pumping estimates.     

Analysis of nitrate pollution control policies in the irrigated agriculture of Apulia Region (Southern Italy): A bio-economic modelling approach

Nitrate leaching is one of the many forms of environmental pollution resulting from irrigation and intensive agriculture. In this work, a method of combining an agronomic simulation model (EPIC) and a mathematical multi-objective programming model is used to analyse the effects of three agricultural policies on farmer’s revenue and nitrate leaching. An evaluation of the net social costs associated with the different policy measures is also given. The farmer’s behaviour in different policy scenarios was studied in terms of selected crops, irrigation technique and method, and adopted management practices with focus on farm management practices and water application efficiency. Irrigation water pricing, subsidies to adopt improved management levels, and taxation on the use of nitrogen fertilizer were examined. A trade-off emerges between the levels of nitrate leaching and net farmer’s revenue more pronounced for nitrogen tax policies than for water pricing. The results obtained indicate that nitrate leaching can be reduced by about 40% with an associated net social cost of 269 €/ha for the water pricing policy, 183 €/ha for the tax on fertilizer and 95 €/ha for subsidies to high efficiency management.     

GIS tools applied to the sustainable management of water resources: Application to the aquifer system 08-29

The sustainable exploitation of water resources requires planning and control methods that allow the incorporation of a great number of spatial and temporal variables. Because of its features, a Geographic Information System (GIS) seems the most suitable tool to aid in the management of available hydric resources. In this study, we have developed a specific GIS within the GESMO Project in order to better manage the 08-29 aquifer system (Mancha Oriental). This tool is intended for use by the JCRMO: Junta Central de Regantes de la Mancha Oriental (General Board of Irrigation Users of Eastern La Mancha), the organism responsible for aquifer management.This system is designed to integrate information from different sources, such as remote sensing, fieldwork data or administrative files with the cadastral subplot as a common reference. One of its functions is to expedite the control and monitoring, in real time, of the exploitation plans, which constitute the legal instrument to regulate water extractions. It will allow us to estimate the spatial and temporal distribution of water extractions needed for crops and their irrigation systems. These estimates will be highly valuable for aquifer modelling. The system also permits display of information on maps for easy handling. This visualisation allow users to more readily participate in decision-making processes.     

An econometric irrigated crop allocation model for analyzing the impact of water restriction policies

The objective of the Spanish government-funded GESMO project is to research on new water policy evaluation and monitoring tools, applied to aquifer 8/23 in the Eastern Mancha, which covers one of the most important areas under the charge of the Júcar Catchment Confederation. The project is to output two types of end products: Decision Support Systems for defining water use policies, including economic impact and environmental simulators within a single multi-criteria decision-making environment and Measure Monitoring and Control Systems employing tele-detection and simulation of crop water needs. The Decision Support Systems will include three, highly complex, theoretical models in a single information technology product: a three-dimensional aquifer 8/23 behavior simulation model, an econometric model to predict crop allocation depending on the economic environment, water availabilities, etc., and an automatic alternative generation and evaluation system based on a multi-criteria methodology. The objective of the system is to advise on possible water policies and how they would materialize into spatially and temporally distributed water quotas (m³/ha) with the objective of both safeguarding the aquifer in the medium and long term and increasing the economic profitability of regional agriculture. In this paper, a regional econometric model is presented for studying the impact of water use quotas on the main irrigated crops allocation in the region.     

An LP-model to analyse economic and ecological sustainability on Dutch dairy farms: model presentation and application for experimental farm “de Marke”

Farm level modelling can be used to determine how farm management adjustments and environmental policy affect different sustainability indicators. In this paper indicators were included in a dairy farm LP (linear programming)-model to analyse the effects of environmental policy and management measures on economic and ecological sustainability on Dutch dairy farms. For analysing ecological sustainability, seven indicators were included in the model: eutrophication potential, nitrate concentration in groundwater, water use, acidification potential, global warming potential, terrestrial ecotoxicity, and aquatic ecotoxicity. Net farm income was included for measuring economic sustainability. The farm structure of “De Marke” formed the basis for three optimisations: (1) basis situation without environmental policy, (2) situation with Dutch environmental policy for 2004, and (3) situation with farm management measures applied at “De Marke”. The Dutch environmental policy was included to comply with the EC nitrate directive. It resulted in lower fertiliser use and consequently in a decrease in sales of maize. This led to a decrease in net farm income of ca. €2500. Including this policy improved most used ecological indicators (except for ecotoxicity) and showed to be an effective tool to reduce the environmental impact of dairy farming. Adapting the model with farm management measures applied at experimental farm “De Marke” resulted in even better ecological performance compared to the situation with environmental policy. Nonetheless this increase in ecological performance led to a considerably lower net farm income (€14,500).     

Farm types for beef production and their economic success in a mountainous province of northern Vietnam

The objective of this study was to compare the management and economic success of beef production by three types of farm in northwestern Vietnam. The potential of household farms to supply beef for the market and their competition with large farms were examined.The fieldwork was done in 2007 on 73 farms consisting of 58 small mixed farms (small farms), 10 medium mixed farms (medium farms) and 5 specialised large-scale beef farms (large farms) in Son La province. The three types of farm differed in ethnicity (Thai, H’mong, and Kinh), remoteness (lowland, highland), production objectives (subsistence, market output), degree of specialization (mixed farm, specialised beef farm) and integration of production (single farmers, cooperative). Data on biological productivity, inputs and outputs, and the social contribution of cattle production were collected by household and key person interviews, participatory rural appraisal tools and cattle body measurements. Economic values were derived by assessment of market or replacement costs. Quantitative data analysis was done with linear models (PROC GLM) in the SAS software (version 9.1).Lowland small farms had higher costs for cattle production than the highland farms (0.8 Mill. VND head⁻¹ year⁻¹ compared with 0.02 Mill. VND head⁻¹ year⁻¹, respectively). The large farms had high production costs, with an average of 2.5-3.6 Mill. VND head⁻¹ year⁻¹. Cattle brought high benefits of non-cash values to the household farms. The total revenue from cattle was in the range 4.5-11.5 Mill. VND head⁻¹ year⁻¹, which depended on the use of non-market functions of cattle on the household farm. The value of net benefit/kg live weight (LW) of lowland small farms with an average of 39,000 VND/kg LW was significantly higher than that of the medium and small farms in the highlands (26,000 VND/kg LW). However, the small farms kept fewer cattle than the medium farms (average of 2-4 cattle/farm compared with 9 cattle/farm, respectively) because of forage and labour shortages and have no option to further develop cattle production. Keeping larger numbers of cattle based on available natural pasture brought high benefit from stock value as farm liquidity to only the medium farms. This was the most promising type of farm for future development of beef production, given its actual success and the availability of underutilised resources. Large-scale farms suffered high economic losses of 0.3-1.4 Mill. VND cattle⁻¹ year⁻¹, due to the lack of professional management, high feed costs and low animal performance, and showed no potential for developing cattle production.     

Irrigated agriculture in the Guadiana River high basin (Castilla-La Mancha, Spain): environmental and socioeconomic impacts

This article is concerned with the management of the Guadiana River high basin's water resources. The region of Castilla-La Mancha in general, and Western La Mancha and the Campo de Montiel in particular, are areas where agriculture has great economic importance. This activity is the principal water consumer, but it is necessary to take account of ecological and social considerations if two important objectives are to be achieved. Firstly, to keep wetlands and biodiversity. Secondly, to maintain natural resources which are vital if the area's future is to be assured. The paper criticizes the mechanical and partial methodological focus which has been used by conventional economics and agriculture. Thus, it supports an integrated and multidisciplinary view that recognises the region's biophysical and social characteristics in such a way that policies applied respect it.     

Characterising rice-based farming systems to identify opportunities for adopting water efficient cultivation methods in Tamil Nadu, India

Efficient water use in rice cultivation is a prerequisite for sustaining food security for the rice consuming population of India. Novel rice production practices, including water-saving techniques, modifications in transplanting, spacing, weeding and nutrient management, have been developed and shown to be effective on farm, but adoption of these techniques by farmers has remained restricted. Potential constraints include technical difficulties with new practices, and labour and gender issues which differ between farms. On the basis of a rapid survey of 100 rice-based farms, four farm types were identified based on their socio-economic and biophysical characteristics. Detailed farm surveys were conducted on three representative farms of each farm type to evaluate land use patterns, use of inputs such as water, labour, nutrient, capital and machinery, income from crop and animal production and off-farm activities. Opportunities exist for one or more new rice cultivation techniques to be adopted in all the four farm types. For all farm types, however, the opportunities for use of water-saving irrigation were the least promising. In general, adoption of water-saving irrigation will not improve farmers’ livelihoods despite its importance in reducing water scarcity problems at regional scale. At farm scale, the potential for adoption of water-saving irrigation depends on the season, location of fields and the irrigation source. Changes in government policies such as rules and regulations, pricing, institution building and infrastructure development, as well as training and education of farmers are needed to improve the adoption of modified methods for rice cultivation.     

Pricing of irrigation water under alternative charging methods: Possible shortcomings of a volumetric approach

The European water framework directive aims to protect the environmental quality of water and encourage its efficient use. EU member states are required to implement efficient water management systems and appropriate water-pricing methods. This paper examines the economic effects that may arise given the introduction of two different methods for pricing irrigation in the Mediterranean area. The considered pricing methods charge farmers for the costs incurred by water user associations (WUAs) in managing water distribution networks. The first method, based on the metered use of water by farms, is known as the volumetric pricing method. The second is an area-based pricing method, whereby fees are charged per hectare according to the estimated average water use for each crop. The economic effects and the impacts on the water usage of these two schemes are analyzed using a mathematical model that represents the farm sector in a Mediterranean area that relies on a dam for irrigation. The possible effects are analyzed under two scenarios: first, the methods are applied to the observed water-pricing conditions, second, an additional charge is introduced to recover unaccounted costs of the water supply system (e.g., long-term costs related to infrastructure, and the operational and maintenance costs of dams) in line with the water framework directive principle of cost recovery. The results show that the introduction of an additional charge via the volumetric pricing method could stimulate the substitution of water provided via collective networks with groundwater. This could adversely affect the financial situation of the WUA and have negative environmental consequences. This negative outcome does not arise in the case that an additional charge is applied via the area-based pricing method.     

Minimisation or remediation: A cost benefit comparison of two approaches for managing irrigation-induced deep percolation

We compare the net present costs of two approaches for managing irrigation-induced deep percolation under border-check irrigated pasture: (1) conversion from border-check irrigation to sprinkler irrigation to minimise deep percolation and (2) installation of a subsurface drainage system to extract excess deep percolation under the existing border-check system. Results for a dairy farm in northern Victoria, Australia, show that conversion to sprinkler irrigation is the more cost-effective approach. The net present cost of the second approach varies across an irrigation landscape, depending on the most suitable subsurface drainage and disposal system that can be used for a particular location. Where an aquifer is high yielding and of low salinity and thus drainage water is suitable for reuse on farm, tubewell drainage and farm reuse of drainage water provides a viable alternative to conversion from border-check irrigation to sprinkler irrigation. Where tubewell drainage or farm reuse is not feasible, sprinkler irrigation is more cost-effective than border-check irrigation with subsurface drainage.     

Irrigation scheduling and water availability at watercourse command

A model that simulated the irrigation schedules of a farm at watercourse command was developed to predict net farm return, benefit-cost ratio, water use, percent water utilized, deep percolation, rainfall contribution and net return per unit of water applied including rainfall. Schedules for three selected farms on a watercourse command of Tw #62394L from MONA, Sargodha, Pakistan were simulated with 3 fixed-rotation and 2 demand strategies to evaluate the allowable soil water depletion criteria. Evaluation of the simulations (1973–82) showed that the water availability reduced the net farm return of 15 and 31% at the middle and tail farms, respectively, from that of the head farm. Therefore, the existing water allocation procedure (WARABANDI) should include watercourse conveyance losses to provide equitable water distribution on a watercourse command. Demand water availability can increase the net farm return of 25 and 26% in strategies 4 and 5, respectively, by changing the fixed-rotation system to a demand system. Changing the fixed-rotation system to a demand system requires either the use of existing private tubewells or the installation of new private tubewells.     

Modelling the fate of water and nitrogen in the mixed vegetable farming systems of northern Tasmania, Australia

A combination of high input management systems, high annual rainfall and deep, permeable soils in northern Tasmania create conditions that are conducive to high drainage and nitrogen losses below the root zone. An understanding of the extent and mechanism of such losses will enable farm managers and their consultants to identify and implement more sustainable management practices that minimise potential adverse financial and environmental consequences. Analysing the fate of water and nutrients in farming systems is complex and influenced by a wide range of factors including management, soil characteristics, seasonal climate variability and management history of the paddock/farm in question. This paper describes a novel farm system modelling approach based on the model APSIM, for analysing the fate of nitrogen and water in mixed vegetable-based farming enterprises. The study was based on seven case farms across the Panatana catchment in northern Tasmania. Substantial simulated drainage losses (>100 mm average seasonal loss) were apparent for all crop and rotation elements across all farms in response to the surplus between crop water supply and crop water use. Crop nitrogen demand was found to be close to crop nitrogen supply for all crop and pasture rotation elements with the exception of potato, which had an average surplus nitrogen supply of 89 kg N/ha. This resulted in potato having much higher nitrate nitrogen leaching losses (32 kg N/ha) compared to other crops (<10 kg N/ha). Simulations suggest that practicable management options such as deficit-based irrigation and reduced N fertiliser rates will maintain current levels of productivity while reducing potential offsite N loss and generating significant financial savings via reduced input costs.     

Improvement of irrigation management towards the sustainable use of groundwater in Castilla-La Mancha, Spain

The great expansion of irrigated lands using groundwater has often caused the exploitation of aquifer reserves beyond their recharge capacity. The development of management tools which can harmonize resource exploitation with reserve sustainability is the objective of an interesting experience being accomplished in the aquifer 08.29 in Mancha Oriental, Spain. This paper offers a summary of this ongoing project (GESMO), pointing out the specific role of the Irrigation Advisory Service. The general objective of the project is to create an integrated and integral management system of the aquifer as well as to prepare appropriate techniques for its adequate exploitation. Integral management means that both supply and demand management are considered, including the socio-economic and environmental perspectives. The concept of integrated management implies that the process must involve the majority of economic and social agents affected.

Management is founded on a Decision Support System (DSS) which takes into consideration different possible options. The DSS must contemplate the impacts on the environment, mainly the aquifer reserve losses and the increase of nitrates concentration in groundwater. The project directly affects more than 5000 agricultural users, irrigating about 100 000 ha with the aquifer water resources, as well as the whole population living in this region. Results of this project, including irrigation technologies developed may be useful for other areas in the Mediterranean Basin where similar cases occur.     

Economic analysis of water allocation policies regarding Nile River water in Egypt

The Government of Egypt is currently implementing projects that expand irrigated area on the Sinai Peninsula and in the southern desert. Those projects will reduce the supply of Nile River water available to farmers in the Nile Delta, which is a heavily populated and highly productive agricultural region. The southern desert project will obtain water directly from Lake Nasser, while a mixture of Nile River water and drainage water will be delivered to the Sinai. The true costs of the projects include the opportunity costs of water and capital that could be used alternatively in the Nile Valley and Delta, or in other productive endeavors. Economic analysis generates optimizing criteria that describe the role of scarcity values (opportunity costs) in determining the allocation of Nile River water that will maximize net social benefits. Policy implications are derived by comparing those criteria with the criterion that farmers implement when maximizing profits from crop production. A small-scale simulation model demonstrates the potential impact of water allocation policies on regional net revenues. Results are discussed within the context of a broader view of national goals that include promoting economic growth, achieving food security, and enhancing the quality of life for Egyptians.     

Proceedings of the Sixth International Conference on Precision Agriculture and Other Precision Resources Managemen on CD-ROM | Robert,P.C. et al., (Ed.), American Society of Agronomy/Crop Science Society of America/Soil Science Society of America,Madison, WI, 2003, USA, 2095 pp. Price: US$14.00.CD-ROM

The objective of this paper is to examine the impacts of terminating rice [Oryza sativa] irrigation earlier than usual. One straightforward result of this would be the associated cost savings (≈$10 ha⁻¹ per irrigation or more with deep wells) without placing a value on the water itself. However, another option exists for some farms. An assumption is that the typical farm will be constrained from irrigating all of the soybean [Glycine max (L.) Merr] crop due to constraints in any or all of water supply, pumping capacity, and labor availability. In these cases, a portion of the land in soybean production would be non-irrigated for the first part of the growing season. This study explores the possibility of transferring irrigation water to the soybean crop after the needs of the rice crop are met. If rice and soybean planting dates are planned optimally, this partial irrigation can lead to substantial soybean yield improvements and therefore a more profitable rice/soybean production system. On average, across a 41 year period, net revenue gains from partially irrigating the soybean crop were consistently positive, ranging from $41 to $458 ha⁻¹. While these numbers are interesting, the reader is cautioned that the results are based on simulation models and therefore the marginal analysis results are more realistic. On clayey and silt loam soils at Keiser and Stuttgart, respectively, the change in returns for moving from the least to the most water saving rice irrigation strategy was $190 and $99 ha⁻¹, respectively. In addition, for any given year, financial losses are typically restricted to the irrigation setup costs of $17 ha⁻¹. The irrigation termination strategies therefore show high economic potential with little risk of loss.     

Typology of cereal-sheep farming systems in Castile-La Mancha (south-central Spain)

There is still no pan-European assessment of the typology of low-intensity farming systems and of the changes which they are undergoing under current European Union (EU) farm policy. This study examines the variability of farm structure and farming practices of a typical cereal-sheep farming system under continental Mediterranean conditions with the aim of providing regional data of policy relevance. The collection of quantitative and qualitative data was planned with collaborative effort from regional extension agencies and followed the Delphi technique. Arable land in Castile-La Mancha occupied more than 70% of total agricultural land in 1997, the rest being natural pasture, shrub-steppe, and Mediterranean forest. Dry low-intensity arable systems still included a sizeable proportion of fallow to cropped land (20%) or somewhat more than 1,000,000 ha, and the winter cereal stubble was often grazed by sheep. These systems were of low intensity in the sense that they used low inputs per ha, particularly of nutrients and agrochemicals. They involved the exploitation of land, particularly for grazing, on an open and large scale. In this sense, they can also be considered extensive systems. On average, only 20% of arable farmers kept sheep, while 80% of the sheep producers were landless pastoralists. Young farmers tend to be disinclined to became involved in the sheep sector, because of the harsh working conditions of sheep farming operations. Response to new economic circumstances involved the evolution of traditional practices with corresponding lower use of farm labour. Although still low-intensive, these systems can be considered as modified forms of traditional practices which have responded to new technologies and the need to cut labour costs. The new objectives for agriculture in Castile-La Mancha, must create or maintain a way of life that is socially and economically attractive to young farmers, without the acceptance of environmentally damaging practices. These new objectives will require a new regionally-targeted EU aid scheme. In turn, there is a need to understand regional agriculture systems before we can hope to achieve successful policy.     

种植类家庭农场的支撑保障体系建设

在广泛的社会调查和家庭农场案例分析的基础上,提出了种植类家庭农场的支撑保障体系建设策略。一是优化家庭农场运行环境,强化家庭农场的条件建设和政策法规支撑;二是完善公共政策支持策略,推进家庭农场的快速发展;三是加强农业社会化服务体系建设,实现规模化、商品化、专业化生产和社会化服务的有机结合;四是加强农业科技服务体系建设,提高家庭农场生产经营的科技含量。      

Dam safety management for sustainable farming businesses and catchments

In most countries, owner responsibility exists under Common Law to manage and maintain dams according to current standards. However, farm dam safety in Australia is being flouted and the sustainability of farming businesses compromised because of the potential and severe consequences of dam failure. This paper explores management and policy issues associated with safety of farm dam water storage through a comparison of developments in two Australian states against international benchmarks. Historical review and a longitudinal study over a 12-year period provides the basis for case analysis and demonstrates the application of the benchmarked model policy selection guidelines. Research results show South Australia is lagging international best practice in a number of ways whilst Tasmania provides leadership. The contribution of this paper is a regulatory mix analysis approach, incorporating a cost-effective spillway safety engineering/accounting tool, developed and demonstrated through Australian case studies, that can be applied by any jurisdiction wanting to check and/or improve its farm dam safety management and provide a clearer analysis of the social and environmental costs and threats associated with on-farm dam safety issues.     

Using economic incentives and regulations to reduce seawater intrusion in the Batinah coastal area of Oman

Excessive groundwater abstraction is a major problem in Oman, primarily in the Batinah coastal area where it results in seawater intrusion. The Government began to address the problem in the 1990s by encouraging the use of more efficient irrigation systems, replacing date palms with winter vegetable crops and using treated wastewater for municipal irrigation. However, 15 years later, seawater intrusion in the Batinah aquifers is still advancing at an alarming pace. This paper analyses the relative merits of strategies to control groundwater pumping based on water quotas, electricity quotas and electricity pricing. A cost benefit approach is used to evaluate the feasibility of three strategies over a period of 25 years and to compare them to the “business as usual” option. Results show that the net present loss to the community when no active policy is implemented amounts to (−$288) million. Imposing water quotas on tubewells would give a net present benefit of $153 million. However, such quotas would give the lowest present benefit and create inequity among farmers. Other possible approaches would be to control the pumping of groundwater from all wells - tubewells and dug wells - by enforcing energy quotas and by increasing the price of electricity used to pump water. The net present benefits would be greater and the costs to farmers would be more fairly spread. The results of cost-benefit analysis show that enforcing an electricity quota, coupled with removal of the subsidy on the electricity price, is the easiest and most equitable solution to implement.     

A systems approach to analyse the effects of Flemish manure policy on structural changes and cost abatement in pig farming

Animal production in the Flemish region and pig production in particular is intensive and causing external problems related to manure disposal. At a regional level, manure disposal can be regarded as a problem of distributing the manure from farms with a surplus to farms with a shortage or to disposal alternatives. Total disposal costs will depend on the amount of manure surplus and on the location dependent disposal cost per unit. Disposal costs are an economic incentive for structural changes and cost abatement investments at farm level which will, in turn, influence the regional disposal. In order to simulate these interactions, an integrated system of models describing the regional manure disposal coordination system is developed, composed of a farm level component, an aggregation module and a regional disposal model. The possibilities for disposal cost abatement at farm level are analysed through LP modelling of representative farms. Incentives for structural change are derived from the shadow prices of the housing and land constraints in the model. Manure separation is analysed as an example of cost abatement investments.