Land-use intensification and environmental degradation: empirical evidence from irrigated and rain-fed farms in south eastern Nigeria

When evaluating the potential of irrigation for agricultural production one must consider more than the technical and financial potential and feasibility of the scheme. Issues of environmental and social sustainability must also be considered. The purpose of the paper is to develop a framework for assessing the sustainability of an irrigation scheme and apply it in the context of one such scheme in south eastern Nigeria. The framework for assessment is based on a comparison of differential changes in environmental quality with and without the scheme, and before and after the scheme. The author does this by using measured soil characteristics for irrigated and adjacent rain-fed plots of agricultural land; and socio-economic analysis of other environmental and social impacts of the irrigation scheme. Data were collected through a field survey of the selected irrigated and rain-fed farm plots, qualitative interviews with the farm owners and relevant secondary sources. The analyses find that the soils of the irrigated farms have been significantly degraded more than those of the rain-fed farms to the extent that precludes sustainable practice of arable agriculture on irrigated land in the study area. About 9% of the soils of the irrigated land have been degraded to the extent that they are no longer suitable for arable agriculture. Analyses of the qualitative interviews also find other bio-physical, social and economic impacts that significantly constrain long-term sustainability of arable agriculture in the study area.     

A multicriteria model for planning agricultural regions within a context of groundwater rational management

Current international research focuses on topics like sustainable development, regional planning, environmental decision making and implementation, biodiversity conservation plus a number of other relevant issues, especially at times of economic crisis as today. Economic growth and environmental protection can go hand in hand, provided that decision makers develop and use tools and insights targeting in the implementation of successful and robust long term policies. This paper was developed in the framework of a European research project and implements a Multicriteria Mathematical Programming model that optimises the sustainable management of agricultural regions taking in account the available resources (land, labour, capital) and environmental parameters (agrochemicals, water consumption). The model achieves the optimum farm plan in the area combining different criteria to a utility function under a set of constraints and the spatial integration of the vulnerability maps of the regions into the model enables the regional authorities to design policies for the optimal agricultural development and the groundwater protection from the agricultural land uses. Furthermore, the model is used to simulate different scenarios and policies by the local stakeholders, due to changes on different social, economic and environmental parameters. In this way the decision makers can achieve alternative farm plans and agricultural land uses as well as to estimate economic, social and environmental impacts of different policies. The model has been applied to an agricultural region in Northern Greece and proved to be a valuable tool in the implementation of environmental policies and actions, especially in agricultural regions in a delicate balance as the study area.     

The promising spread of sustainable agriculture in Asia

Despite great successes in increasing food production, Asia still faces enormous food security challenges. Most commentators agree that there will have to be increases in food production from existing agricultural land, but many are pessimistic about the future, judging likelihood of success on the basis of past performance of 'modern' agricultural development. Sustainable agriculture, though, offers entirely new opportunities, by emphasising the productive values of natural, social and human capital, all assets that Asian countries either have in abundance or that can be regenerated at relatively low financial cost.
This paper sets out an assets-based model of agricultural systems, together with a typology of eight approaches for sustainable agriculture improvements. In the 16 projects/initiatives spread across eight countries that are analysed, some 2.86 million households have substantially improved total food production on 4.93 million hectares, resulting in greatly improved household food security. Proportional yield increases are greatest in rainfed systems, but irrigated systems have seen small cereal yield increases combined with added production from additional productive system components (such as fish in rice, vegetables on dykes). The additional positive impacts on natural, social and human capital are also helping to build the assets base so as to sustain these improvements in the future.
This analysis indicates that sustainable agriculture can deliver large increases in food production in Asia. But spreading these to much larger numbers of farm households will not be easy. It will require fundamental policy reform.     

Agricultural Development and Associated Environmental and Ethical Issues in South Asia

South Asia is one of the most densely populated regions of the world, where despite a slow growth, agriculture remains the backbone of rural economy as it employs one half to over 90 percent of the labor force. Both extensive and intensive policy measures for agriculture development to feed the massive population of the region have resulted in land degradation and desertification, water scarcity, pollution from agrochemicals, and loss of agricultural biodiversity. The social and ethical aspects portray even a grimmer picture of the region with growing poverty mainly, amongst small farmers, food scarcity, and overall poor quality of life. This article reviews the historical perspective of agriculture development in the region and gives a panoramic view of the policy initiatives and their environmental as well as social and ethical spin-offs. The aim is to explore the environmental and ethical dimensions of the agricultural development in South Asia and recommend a holistic approach in formulating plans and programs to combat environmental degradation, hunger, and poverty resulting from unsustainable agricultural practices.     

POTENTIAL EFFECTS OF CLIMATE CHANGE ON AGRICULTURAL WATER USE IN THE SOUTHEAST U.S.1

ABSTRACT: Climate change has the potential to have dramatic effects on the agricultural sector nationally and internationally as documented in many research papers. This paper reports on research that was focused on a specific crop growing area to demonstrate how farm managers might respond to climate-induced yield changes and the implications of these responses for agricultural water use. The Hadley model was used to generate climate scenarios for important agricultural areas of Georgia in 2030 and 2090. Linked crop response models indicated generally positive yield changes, as increased temperatures were associated with increased precipitation and CO2. Using a farm management model, differences in climate-induced yield impacts among crops led to changes in crop mix and associated water use; non-irrigated cropland received greater benefit since irrigated land was already receiving adequate moisture. Model results suggest that farm managers will increase cropping intensity by decreasing fallowing and increasing double cropping; corn acreage decreased dramatically, peanuts decreased moderately and cotton and winter wheat increased. Water use on currently irrigated cropland fell. The potential for increased water use through conversion of agriculturally important, but currently non-irrigated, growing areas is substantial.     

LOW-INPUT AGRICULTURE AS A GROUND WATER PROTECTION STRATEGY1

ABSTRACT: Protection of ground water quality is of considerable importance to local, state, and federal governments. This study uses a 15-year mathematical programming model to evaluate the effectiveness of low-input agriculture, under alternative policy scenarios, as a strategy to protect ground water quality in Richmond County, Virginia. The analysis considers eight policy alternatives: cost-sharing for green manures, two restrictions on atrazine applications levels, chemical taxation, a restriction on potential chemical and nitrogen levels in ground water only and in surface and ground water, and two types of land retirement programs. The CREAMS and GLEAMS models were used to estimate nitrate and chemical leaching from the crop root zone. The economic model evaluates production practices, policy constraints, and water quality given a long-term profit maximizing objective. The results indicate that low-input agriculture alone may not be an effective ground water protection strategy. The policy impacts include partial adoption of low-input practices, land retirement, and the substitution of chemicals. Only mandatory land retirement policies reduced all chemical and nutrient loadings of ground water; however, they did not promote the use of low-input agricultural practices.     

Environmental sustainability and land reform in South Africa: A neglected dimension

Despite supportive policy frameworks and increased environmental awareness, a growing body of evidence indicates that environmental sustainability is not central to planning and decision-making processes in land reform in South Africa. Increasing pressures on government to meet land reform targets, cumbersome and often inappropriate environmental assessment procedures, and a confusing multitude of laws all contribute to neglect of long-term environmental sustainability considerations in land reform. This is exacerbated by poor recognition of resource rights, a lack of proactive and pre-emptive environmental management plans, and insufficient implementation capacity. This paper argues that the early incorporation of environmental sustainability issues in pre-settlement and post-settlement land reform planning processes could significantly improve the environmental, social and economic outcomes of these projects. A simple, participant-driven environmental sustainability assessment tool is proposed to achieve these environmental and developmental goals.     

关于世行贷款农业灌溉项目环境影响评价问题的讨论

农业灌溉工程建设是我国第十二个五年规划纲要中提出的全面加强农田水利建设工作的重要组成部分。随着越来越多农业灌溉项目的兴建及我国环境影响评价制度的发展,农业灌溉项目的环境影响评价也在不断发展和完善中。本文根据世行贷款项目——中国四川武都农业灌溉项目环境影响评价实践和工作经验,分析总结了世界银行及我国在农业灌溉项目环境影响评价工作方面的特点和要求,其中世界银行在有些方面,如评价等级、公众参与等与国内环评要求基本一致,而有些方面,如回顾性评价、替代方案分析、累积性影响分析、环境管理计划、移民安置行动计划、病虫害管理计划等在国内环境影响评价中尚未引起足够的关注或与世界银行要求存在较大差异,值得我国环评工作参考和借鉴。     

FARM-LEVEL MANAGEMENT OF DEEP PERCOLATION EMISSIONS IN IRRIGATED AGRICULTURE1

ABSTRACT: Source control costs for deep percolation emissions from irrigated agriculture are analyzed using a farm-level model. Crop area, irrigation system and applied water are chosen to maximize the net benefits of agricultural production while accounting for the environmental damages and disposal costs of those emissions. Deep percolation is progressively reduced as environmental and disposal costs are increased. This occurs primarily through the adoption of more efficient irrigation technology and reductions in applied water for a given technology Higher surface water prices, such as through irrigation reform and constrained surface supplies, are additionally considered in light of the drainage problem, as are the effects, both short- and long-term, on ground water use.     

SIMULATION AND DECISIONMAKING: THE PLATTE RIVER BASIN IN NEBRASKA1

Substantial conflict exists over water management and allocation in the Platte River Basin of Nebraska. An interdisciplinary computer simulation model, representing the water quantity, water quality, environmental, and economic dimensions of the conflict, was developed in order to analyze the tradeoffs among allocation scenarios. Most importantly, decisionmakers and interest groups were involved in model development. Simulation results for a base case and two scenarios are presented. One scenario favors protection of instream flow for wildlife; the other favors water diversions for agriculture. Impacts of the instream flow scenario, as measured by the amount of land irrigated, groundwater levels, the amount of wildlife habitat for cranes and catfish, and net agricultural benefits did not differ greatly from those of the base case. However, impacts of the diversion scenario were substantial. On the negative side, instream flows and wildlife habitat declined an average of 39 percent; while, on the positive side, groundwater levels and net agricultural benefits each increased 6 percent. The modeling process was successful insofar as it promoted an understanding among the highly diverse interest groups of the systems nature of the Basin. One agreement on a water diversion schedule among three of the parties has been reached, partly as a result of this process. More comprehensive compromises have not yet been forged. Our experience, however, indicates that modeling success at the policymaking level depends more on the extent to which the policymakers understand the model than it does on model sophistication.     

AGRICULTURE, WATER AND ENVIRONMENT IN BOTSWANA: A PROBLEM OF POLICY

In many countries, an increasing amount of attention is being paid to the economic and environmental repercussions of mineral resources development, and in particular to the problems of industrialisation of an agricultural society. In Botswana, the discovery of and planning for the development of nickel deposits is an important element of national policy. However, often overlooked is the basic and continuing role that has to be provided by the agricultural sector. The pressure of people and of livestock on the land, and the extension of cultivation into increasingly fragile environments where the availability of water is a critical constraint, pose serious problems for policy makers. The author examines the dilemma in a case study of Botswana, showing how changes in the agricultural sector have precipitated problems of water supply and of environmental stress. The need for inter-disciplinary approaches to policy making is underscored, together with detailed and integrated studies of the dimensions of these inter-related problems. The problem of the availability of water in adequate quantities and of appropriate quality has become a serious policy concern. Later this year the United Nations Conference on Desertification will address the broad scope of the relationships between man, land and water. This article examines one example of these changing relationships.     

Salt-induced land and water degradation in the Aral Sea basin: A challenge to sustainable agriculture in Central Asia

Expansion of irrigated agriculture in the Aral Sea Basin in the second half of the twentieth century led to the conversion of vast tracks of virgin land into productive agricultural systems resulting in significant increases in employment opportunities and income generation. The positive effects of the development of irrigated agriculture were replete with serious environmental implications. Excessive use of irrigation water coupled with inadequate drainage systems has caused large‐scale land degradation and water quality deterioration in downstream parts of the basin, which is fed by two main rivers, the Amu‐Darya and Syr‐Darya. Recent estimates suggest that more than 50% of irrigated soils are salt‐affected and/or waterlogged in Central Asia. Considering the availability of natural and human resources in the Aral Sea Basin as well as the recent research addressing soil and water management, there is cause for cautious optimism. Research‐based interventions that have shown significant promise in addressing this impasse include: (1) rehabilitation of abandoned salt‐affected lands through halophytic plant species; (2) introduction of 35‐day‐old early maturing rice varieties to withstand ambient soil and irrigation water salinity; (3) productivity enhancement of high‐magnesium soils and water resources through calcium‐based soil amendments; (4) use of certain tree species as biological pumps to lower elevated groundwater levels in waterlogged areas; (5) optimal use of fertilizers, particularly those supplying nitrogen, to mitigate the adverse effects of soil and irrigation water salinity; (6) mulching of furrows under saline conditions to reduce evaporation and salinity buildup in the root zone; and (7) establishment of multipurpose tree and shrub species for biomass and renewable energy production. Because of water withdrawals for agriculture from two main transboundary rivers in the Aral Sea Basin, there would be a need for policy level interventions conducive for enhancing interstate cooperation to transform salt‐affected soil and saline water resources from an environmental and productivity constraint into an economic asset.     

Is environmental research and development on the right track? Australian examples

Summary The development products of environmental research lag behind in Australia. The conventional technology transfer model may not apply where environmental research, especially in the social sciences, is still seen as marginal to society. Pragmatic planning is needed for strategic security in times of trouble ahead. Cultural alignment with technological advance allows seduction by laboratories, white gladiatorial coats and expensive equipment imparting high credibility. A correctness for research futures disallows more radical pathways by the use of profit watchers, waste watch committees, technocrats and masculinist political views.A new protocol for environmental research and development calls for less complacency, scrutiny of political and military investment in nuclear futures, greater public policy analysis of issues such as pesticides in Australia's cotton industry, more attention to natural systems thresholds, radical review of social mores, more flexible management systems and closer links between strategic land use and environmental planning.She currently works for the New South Wales Department of Water Resources as a Senior Executive Officer. She has published widely on environmental policy analysis and water planning, and is a Director of Australia's National Land and Water Resources Research and Development Corporation.     

Modeling the relationship between land use and surface water quality

It is widely known that watershed hydrology is dependent on many factors, including land use, climate, and soil conditions. But the relative impacts of different types of land use on the surface water are yet to be ascertained and quantified. This research attempted to use a comprehensive approach to examine the hydrologic effects of land use at both a regional and a local scale. Statistical and spatial analyses were employed to examine the statistical and spatial relationships of land use and the flow and water quality in receiving waters on a regional scale in the State of Ohio. Besides, a widely accepted watershed-based water quality assessment tool, the Better Assessment Science Integrating Point and Nonpoint Sources (BASINS), was adopted to model the plausible effects of land use on water quality in a local watershed in the East Fork Little Miami River Basin. The results from the statistical analyses revealed that there was a significant relationship between land use and in-stream water quality, especially for nitrogen, phosphorus and Fecal coliform. The geographic information systems (GIS) spatial analyses identified the watersheds that have high levels of contaminants and percentages of agricultural and urban lands. Furthermore, the hydrologic and water quality modeling showed that agricultural and impervious urban lands produced a much higher level of nitrogen and phosphorus than other land surfaces. From this research, it seems that the approach adopted in this study is comprehensive, covering both the regional and local scales. It also reveals that BASINS is a very useful and reliable tool, capable of characterizing the flow and water quality conditions for the study area under different watershed scales. With little modification, these models should be able to adapt to other watersheds or to simulate other contaminants. They also can be used to study the plausible impacts of global environmental change. In addition, the information on the hydrologic effects of land use is very useful. It can provide guidelines not only for resource managers in restoring our aquatic ecosystems, but also for local planners in devising viable and ecologically-sound watershed development plans, as well as for policy makers in evaluating alternate land management decisions.     

MULTISOURCE/MULTIQUALITY AGRICULTURAL WATER USE DECISIONMAKING1

ABSTRACT: The importation of water into an existing irrigated agricultural area raises many questions about farm profitability and suggests many adjustment alternatives open to farmers. In particular, how will farmers respond to a new additional water source of differing cost, availability, and quality? Mathematical programming models of representative irrigated farms in Pinal County, Arizona, were developed to project agricultural adjustments to new water from the Central Arizona Project now under construction. The techniques developed have broad application to similar water resource projects involving the conjunctive use of multiple water sources of differing qualities. Regional agricultural activities are described by defining and modeling multiple representative farms which account for economies due to size and different water sources of differing price and quality. Various management schemes can be evaluated by properly selected representative farm models.     

Soil erosion and non-point source pollution impacts assessment with the aid of multi-temporal remote sensing images

Soil erosion associated with non-point source pollution is viewed as a process of land degradation in many terrestrial environments. Careful monitoring and assessment of land use variations with different temporal and spatial scales would reveal a fluctuating interface, punctuated by changes in rainfall and runoff, movement of people, perturbation from environmental disasters, and shifts in agricultural activities and cropping patterns. The use of multi-temporal remote sensing images in support of environmental modeling analysis in a geographic information system (GIS) environment leading to identification of a variety of long-term interactions between land, resources, and the built environment has been a highly promising approach in recent years. This paper started with a series of supervised land use classifications, using SPOT satellite imagery as a means, in the Kao-Ping River Basin, South Taiwan. Then, it was designed to differentiate the variations of eight land use patterns in the past decade, including orchard, farmland, sugarcane field, forest, grassland, barren, community, and water body. Final accuracy was confirmed based on interpretation of available aerial photographs and global positioning system (GPS) measurements. Finally, a numerical simulation model (General Watershed Loading Function, GWLF) was used to relate soil erosion to non-point source pollution impacts in the coupled land and river water systems. Research findings indicate that while the decadal increase in orchards poses a significant threat to water quality, the continual decrease in forested land exhibits a potential impact on water quality management. Non-point source pollution, contributing to part of the downstream water quality deterioration of the Kao-Ping River system in the last decade, has resulted in an irreversible impact on land integrity from a long-term perspective.     

An assessment of Spain's Programa AGUA and its implications for sustainable water management in the province of Almería, southeast Spain

Spain's Programa AGUA was proposed in 2004 as a replacement for the Spanish National Hydrological Plan and represented a fundamental policy shift in national water management from large inter-basin water transfers to a commitment to desalination. Twenty-one desalination facilities are planned for six provinces on the Spanish Mediterranean coast to supplement their water needs. These include the province of Almería that for the last 30 years has endured a net water abstraction overdraft leading to serious reservoir depletion and groundwater imbalances. Rising water use is a result of increasing demand to support irrigated agriculture (e.g. greenhouse horticulture) and for domestic needs (e.g. rapid urban growth and tourism development), which has led observers to question Almería's long-term water sustainability. Desalinated water alone is unlikely to be sufficient to make up these water deficits and water-users will have to accept a move to full-price water recovery by 2010 under the European Union (EU) Water Framework Directive of which Spain is a signatory. Anticipated water efficiencies resulting from higher water tariffs, increasing water reuse and water infrastructure improvements (including inter-basin transfers), in conjunction with increasing use of desalinated water, are expected to address the province's current water overdraft. However, Almería will need to balance its planned initiatives against long-term estimates of projected agricultural and domestic development and the environmental consequences of adopting a desalination-supported water future.     

DEVELOPING COMPETITION FOR WATER IN THE URBANIZING AREAS OF COLORADO1

ABSTRACT: Rapid population growth in the metropolitan area of Denver, Colorado, is causing conflicts over water use. Two cities, Thomton and Westminster, have begun condemnation proceedings against three irrigation companies to secure agricultural water rights for municipal use. This is the first condemnation proceeding against irrigation water rights for municipal use. Should the suit succeed, over 30,000 acres of presently irrigated land will lose its water supply. There are about four hundred landowners in the area; two hundred of these are commercial farmers, including truck, dairy and specialty farms. Total agricultural production amounts to about $8 million per year. About 561 jobs related to agriculture will disappear along with about $4 million in not income. Only 6.4 percent of the farmland along the Front Range is irrigated. Continued urban growth will put pressure on the water supply of much of this land. The interested parties of the region should cooperate to lessen the impact of urban growth on agricultural lands and water by forming a metropolitan water district. Such a district could share costs of development of additional municipal water and develop systems where municipalities would recycle waste water back to the irrigated lands.     

A CONCEPTUAL FRAMEWORK FOR EVALUATING AGRICULTURAL WATER CONSERVATION POTENTIALS1

ABSTRACT: This paper defines types of water losses in irrigated agriculture and outlines potentials for water conservation. Recoverable water “losses” (seepage, leakage, and spillage during storage and conveyance, and surface runoff and deep percolation during irrigation) and irrecoverable losses (evaporation from water and soil surfaces and transpiration from plants) are described and illustrated. Some conservation terms are defined, particularly the distinction between on-farm irrigation efficiency and areawide efficiency. Briefly reviewed are agricultural water conservation technologies and their applicability. The biggest untapped potential for water conservation may be a reduction in irrecoverable losses, especially evapotranspiration. The advantages and disadvantages of reducing recoverable and irrecoverable water losses are described, including possible effects on ground water, energy, salinity, crops, wildlife, and in-stream uses. Such information may be useful in several policy and management issues, e.g., ground water overdraft and possible constraints on crops and sites to be irrigated.