Nitrate pollution control under soil heterogeneity

This article presents results on measures to abate nitrogen pollution when soil heterogeneity is considered by using a dynamic model of corn production. Several policy options for the control of nitrate pollution are evaluated by their cost efficiency. While results show that a nitrogen standard or tax is a good second-best control instrument, neglecting dynamics may lead to the wrong choice of instrument. Other important findings for the design of nonpoint pollution policy measures are that water pricing, as advocated by the Water Framework Directive, is inefficient as a pollution abatement tool, and differentiating control measures by soil type enhances welfare, although welfare gains may be small.     

Controlling nitrate pollution: An integrated approach

The introduction of the EU Water Framework Directive requires policy to address non-point source pollution as part of an overall integrated strategy to improve the ecological status of water bodies. In this paper, we combine an economic optimisation framework with a dynamic simulation model of N transport in the Kennet Catchment to link decisions taken at the farm level to reductions in nitrate concentrations in the River Kennet. We examine a variety of policies targeted at reducing fertiliser use and changing the way in which farm land is used. We find that a tax on nitrogen emerges as the best policy both in terms of cost- and environmental effectiveness. Such a policy involves a considerable reduction in fertiliser use, as well as, a restructuring of land-use away from arable towards increased use of set-aside. Budgetary implications of such a radical move towards set-aside would be huge and hence unlikely to be politically palatable given the objective of reducing the EU budgetary allocation to agriculture. Additionally, the current rise in world demand for food may also mitigate calls for increasing the proportion of land taken out of agricultural production. Although the study succeeds in establishing a link between actions on the farm and nitrate concentrations in the stream water, further work is required to explore the effect of the retention of nitrates in the unsaturated zone and groundwater on this link.     

Determining the economic gains from regulation at the extensive and intensive margins

Among the second-best approaches for the regulation of pollution,little attention has been paid to the distorting effect of intensivemargin policies on the extensive margin. This article shows,within a dynamic framework, that regulation of the intensivemargin has to be complemented by regulation of the extensivemargin. Depending on the elasticity of the pollution functionwith respect to nitrogen use, the appropriate regulation atthe extensive margin is zero, a tax or a subsidy. We show empiricallythat combining a nitrogen tax with land-use taxes is about 18per cent more cost efficient than a nitrogen tax alone and 58per cent more efficient than off-site abatement in the formof groundwater treatment.     

The role of common pool problems in irrigation inefficiency: a case study in groundwater pumping in Mexico

Groundwater depletion is a serious problem in Mexico. Several policy alternatives are currently being considered in order to improve the efficiency of irrigation water use so that extraction of groundwater is diminished. An understanding and quantification of different sources of inefficiency in groundwater extraction is critical for policy design. Survey data from a geographically extensive sample of irrigators is used to gauge the importance of common pool problems on input‐specific irrigation inefficiency. Results show that mechanisms of electricity cost sharing implemented in many wells have a sizable impact on inefficiency of irrigation application. Moreover, irrigation is very inelastic to its own unitary cost. Therefore, results suggest that policies aimed at eliminating electricity cost‐sharing mechanisms would be significantly more effective than electricity price‐based policies in reducing irrigation application. Results also show that well sharing does not affect groundwater pumping significantly, suggesting either a limited effect of individual pumping on water level or absence of strategic pumping by farmers sharing the wells.     

基于水权交易和面源污染控制的农户灌溉施肥行为模型

将水权交易和面源污染控制有机结合,以种植面积、农业用水定额、污染物浓度为约束条件,运用边际分析方法建立农户灌溉施肥行为模型,分析水权交易和排污控制对农户行为的影响。结果表明:灌溉用水量与农作物价格成正相关,与交易水价和边际灌溉成本成负相关;一定范围内肥料施用量与农作物价格成正相关,与边际施肥成本或边际环境成本成负相关。模型证明,当农业用水定额内水权可交易时,水市场的存在和水价政策将激励农户减少灌水量,节约用水。     

The Social Returns of Agricultural Practices for Promoting Water Quality Improvement

Soil erosion leads to various degrees of soil productivity loss and to pollution when contaminants load into watercourses. Practices to conserve soil do not inevitably profit farmers; in fact, for most farmers they do not. Still, in most instances, they do yield net off-farm gains. Especially when on-farm net costs are involved, then for policy intervention purposes it becomes necessary to calculate the social return of such practices. Total off-farm returns depend on the degree of water quality improvement made, the number of water uses and users in a watershed, and society's willingness to pay for such improvement. This paper explores a new method for calculating the degree of water quality change from a loading reduction and its impact on social return. In a case study application for an Ontario watershed, water was used for only two purposes: angling and conveyance. Moreover, the degree of water quality improvement made from sediment and phosphorus reduction through modified agricultural practices was slight. This was mainly because of the presence of pollutants not necessarily originating from agriculture that prevented a substantial increase in water quality. As a consequence, in this case, off-farm benefits from such reductions were low. On the other hand, several agronomic practices resulted in positive on-farm returns.     

EFFICIENT COMPLIANCE WITH AGRICULTURAL NITRATE POLLUTION STANDARDS

Non-point pollutants such as nitrates are difficult to monitor and hence control. This paper considers nitrate abatement policies for the Tyne catchment in northern England. The analysis is based on an aggregate-level LP model which predicts producers' production decisions and estimates the resulting spatial distribution of nitrogen applications and nitrate emissions. The policy evaluation compares a catchment-level nitrate emission quota, a catchment-level nitrogen input quota and nitrogen input quotas targeted at individual land classes as alternative measures to achieve nitrate concentration standards. The results indicate that targeted nitrogen input quotas provide a feasible and relatively efficient abatement policy when a lack of information on individual farms prevents the use of the least cost emission tax.     

Integrated assessment of water framework directive nitrate reduction measures

This article illustrates a statistical approach for deriving farm economic impacts of policy options aiming to reduce nitrate diffuse pollution. Building upon Fezzi et al. (2008) , who assess the costs of Water Framework Directive‐related measures on farm accounts data, we estimate regression models allowing such costs to be predicted for any region for which land use patterns and livestock numbers are known. We derive economic impacts in terms of changes in farm gross margin for (a) reducing inorganic fertilizer application, (b) reducing livestock stocking rates, and (c) converting arable land to ungrazed grassland. A case study of the agriculturally diverse Yorkshire Derwent catchment, in the North of England, demonstrates the overall approach. In addition, for this illustration, we combine these cost estimates with prediction of the water quality changes arising from each measure, derived via an integrated hydrological model of the Derwent. This allows a comparison of cost‐effectiveness. Finally, we implement our spatially explicit approach to target the measures to specific subcatchments identified as being of particular environmental policy interest.     

INCOME TAX DATA AND FARM FINANCIAL STATISTICS

Tracing the income patterns of individual farm operators whose major source of income is generally derived from farming indicates that off-farm income is becoming an increasingly important income component. The relative importance of off-farm income has nearly quadrupled during the last 20 years, rising from about 10 percent of total income to about 37 percent of total income. Most of this off-farm income can be traced to wages and salaries. These fractions are heavily dependent upon relative income levels. In 1970, very low income farmers posted an aggregate net farm loss whereas the $15,000 - $20,000 class secured about three-quarters of their total income from farm sources. In this same year, wages and salaries were generally the prime off-farm income source for farmers with an assessed income of less than $20,000. Dividends and interest were more important to farmers with an income in excess of $20,000. These differences are faithfully reflected in the regional compilations. As a percent of total income, off-farm income ranged from 41 percent in Ontario to about 29 percent in Quebec. The composition of off-farm sources also varies considerably between regions. In 1970 the income position of taxable unincorporated farm operators (who relied on the farm for their major source of income) remained relatively unfavorable. These farmers still had one of the lowest average incomes of any major occupational class in Canada, with an income distribution which was relatively equally distributed between income classes and not unlike that of the national average. These assessed income statistics, of course, are not necessarily indicative of the welfare position of the respective occupational classes. The calculations conducted are simply illustrative of how income tax statistics can be utilized to facilitate our understanding of the income structure in primary agriculture today. The exercise simply underlines the observation that: The fact that there are conceptual differences between income tax data and other data sources should not detract from the usefulness of the income tax data …. Income tax statistics can stand as an independent data source for the analysis of a variety of issues [13]. For many purposes the tax definition of a farm operator may be more operational than the concept of a farmer as defined in the Census of Agriculture. We might profit considerably from further analyses which attempt to disaggregate Census farms into more homogeneous farm-types using the tax statistics available.     

长江中下游城市群农业面源污染氮排放评价及调控

基于清单分析法和排污系数法,对长江中下游城市群农业面源污染氮排放现状进行了评价,并运用灵敏度分析和情景分析方法,模拟和比较了不同调控方案对区域未来氮排放变化的影响。研究结果表明,2011年长江中下游城市群4种污染源向水环境排放的氮总量共计128.27万t,其中,农业种植和畜禽养殖的排放比例分别为58.92%和33.53%,是该区农业面源污染的主要氮污染源。如果不加大对面源污染的治理力度,2011~2020年和2020~2030年长江中下游城市群农业面源污染氮排放量将分别增加16.29%和18.78%;如果采取相关减排措施,2020年和2030年4个城市群的农业面源污染氮排放量将分别比2011年削减15%和25%,并有利于实现区域农村经济增长与环境健康发展的双重目标。建议今后全区农业面源污染氮排放调控的重点在于逐步削减肥料投入、合理优化用肥结构、控制畜禽养殖规模扩张以及促进专业化养殖畜禽废物循环利用等,主要控制地区包括武汉城市圈内的潜江市、孝感市、黄冈市和鄂州市,长株潭城市群内的长沙市和湘潭市,鄱阳湖生态经济区内的南昌市和鹰潭市,以及皖江城市带内的六安市和合肥市。     

Evaluating Input Standards for Non‐Point Pollution Control under Firm Heterogeneity

The efficacy and cost of input standards for reducing nitrate pollution from New Zealand dairy production are evaluated. In contrast to previous studies, firm heterogeneity is explicitly considered through the novel integration of efficient techniques for the calibration and decomposition of large optimisation models. Nitrogen fertiliser application should not be targeted by policy given its minor role in determining emissions. In contrast, livestock intensity is an appropriate base for regulation given its strong correlation with pollutant load. Abatement cost increases as stocking rate declines, but this can be offset at low levels of regulation through utilising slack feed resources to improve per‐cow milk production. Both uniform and differentiated input standards based on livestock intensity achieve substantial decreases in pollutant load at moderate cost. However, because of disparity in the slopes of abatement cost curves across firms, a differentiated policy is more cost‐effective at the levels of regulation required to achieve key societal goals for improved water quality.     

Policy Implications of a Water Quality-constrained Dynamic Model of Nitrogen Fertilizer Use

This paper has demonstrated that the omission of a time lag associated with contaminant transport processes will result in sub-optimal nitrogen fertilizer use by, first, presenting a surface and groundwater quality-constrained dynamic optimization model of nitrogen fertilizer use. Potential groundwater contamination has been presented in a probabilistic manner, with the probability of contaminant level exceeding the MCL.
Second, we have discussed the economic effects of fiscal programs including a user tax and a unit subsidy for the reduction of nitrogen fertilizer use. We have highlighted that the introduction of a unit subsidy program via redeemable coupons transforms the fertilizer market into a market characterized by perceived imperfect competition, and the government subsidy expenditure under imperfect competition is greater than under perfect competition. Therefore, directly incorporating water quality-constraints, and accounting for perceived imperfect competition results in a better understanding of the impacts of government policy.     

Implications of alternative environmental policies on phosphorus loading from poultry litter

Degraded groundwater, impaired swimming, fishing, algae and weed problem are often associated with eutrophication from phosphorus (P) loadings in surface and groundwater. The concentrated growth of poultry industry and over application of litter on pasture lands may lead to excessive nutrient loadings in surface and groundwater. The Cooperative Extension Service recommendation suggests that no poultry litter should be applied if the soil test P exceeds 300 pounds per acre, irrespective of the marginal costs and benefits associated with one more unit of litter application on that piece of land. The objective of this paper is to model the economics of P loadings from poultry litter and analyze the policy implications of Cooperative Extension Service's recommendation on quantity restriction on litter applications with empirical evidence. The results indicate that there exists significant difference in the marginal values of soil between different soil series, indicating that the permit system can achieve the target at a lesser cost. In particular, the society as a whole can gain $2.7 per acre by allocating the litter to soil series 16 instead of soil series 20, provided that the contribution towards groundwater contamination from these two acres are the same.     

Impacts of terrain attributes on economics and the environment: costs of reducing potential nitrogen pollution in wheat production

The economic cost of achieving desired environmental outcomes from uniform and variable rate fertilizer application technologies depends both on market forces and agronomic properties. Using spatial econometric methods, we analyze the impact of nitrogen fertilizer supply by terrain attribute on the yield and protein content of hard red spring wheat grown in Eastern Washington as well as the impact on residual nitrogen. We find significant association with all three. The economic impact of nitrogen restrictions depends critically on both prices and level of the restriction. Uniform application of nitrogen was found to economically outperform variable rate application, but variable rate application provided positive environmental benefits due to less residual nitrogen.     

Estimating the range of economic impacts on farms of nutrient leaching reduction policies

Declining agricultural incomes, increasing concern over rural poverty and sporadic crises such as those of Bovine Spongiform Encephalopathy (BSE) and Foot and Mouth Disease mean that the imposition of further costs on U.K. agriculture are likely to be politically and socially sensitive. Such additional costs are however on the agenda with the implementation of the Water Framework Directive (WFD; European Commission, 2000 ). The WFD aims to achieve “good ecological status” in EU water bodies reducing, inter alia, diffuse pollution from agriculture. In this study, we assess four possible WFD measures proposed to the U.K. Department for Environment, Food, and Rural Affairs: reducing inorganic fertilizer application, conversion of arable land to ungrazed grassland, reducing livestock stocking rates, and reducing livestock dietary N and P intakes. For each measure, changes in farm gross margins (FGMs) are estimated using a dataset of over 2000 farms. In contrast to previous analyses, which have focussed upon mean responses on stylized farms, our approach allows the analysis of the range of impacts across a wide variety of real‐world farms and farm types. Findings reveal high variability in impacts. Cost‐effectiveness analysis indicates that, on average, cropping farms seem capable of reducing nutrient leaching in a more cost‐efficient way than livestock or dairy enterprises.     

Crop Price and Risk Effects on Farm Abatement Costs

Potential leaching losses of nitrogen depend in large part on the crops grown. Since crop selection is a major means of abatement for nitrates in groundwater, it follows that the compliance costs to producers for reducing excess nitrogen is influenced by crop prices. This paper demonstrates the role that crop prices play in determining the level of on-farm abatement costs and even the necessity for regulatory policies to deal with the nitrate problem. Government support programs, specifically the Gross Revenue Insurance Program (GRIP), have increased the relative support for corn, which has higher leachate potential than other crops, and thereby requires increased abatement effort. The required level of abatement is less when risk aversion is considered than under risk neutrality, since the variability in returns among rotations is related to the degree of emissions generated. Changes in the mean and variance of relative output prices can significantly alter the optimal crop mix, leachate potential and on-farm abatement efforts. Subsequently, there is an effect on abatement costs associated with alternative environmental control instruments, which in turn affects policy design through issues such as political feasibility and equity considerations.     

Upstream demand for water use by new tree plantations imposes externalities on downstream irrigated agriculture and wetlands*

Large‐scale tree plantations in high rainfall upstream areas can reduce fresh water inflows to river systems, thereby imposing external costs on downstream irrigation, stock and domestic water users and wetland interests. We take the novel approach of expressing all benefits and costs of establishing plantations in terms of $ per gigalitre (GL) of water removed annually from river flows, setting upstream demands on the same basis as downstream demands. For the Macquarie Valley, a New South Wales sub‐catchment of Australia’s Murray‐Darling Basin, we project changes in land and water use and changes in economic surpluses under two policy settings: without and with a policy requiring permanent water entitlements to be purchased from downstream parties, before plantation establishment. Without the policy, and given a high stumpage value for trees ($70/m³), upstream gains in economic surplus projected from expanding plantations are $639 million; balanced against $233 million in economic losses by downstream irrigators and stock and domestic water users for a net gain of $406 million, but 345 GL lower mean annual environmental flows. With the policy, smaller gains in upstream economic surplus from trees ($192 million), added to net downstream gains ($138 million) from sale of water, result in gains of $330 million with no reduction in environmental flows. Sustaining the 345 GL flow for a $76 million (406–330) reduction in gains to economic surplus may be seen to cost only $0.22 million/GL; but this is much lower than the market value of the first units of that water to agriculture and forestry.     

Abstracts of Award-Winning Theses

This thesis determines the tradeoff between producer welfare and the provision of environmental benefits, through reduced soil erosion and fertilizer applications, on agricultural working land. A land-use allocation model of two Iowa counties is formulated as a mathematical programming problem, building upon the Takayama and Judge framework. Slope is used to reflect terrain heterogeneity, such that the spatial allocation of land-use practices impacts economic and environmental outcomes via a yield damage function and differentiated rates of soil erosion. The model differs from prior empirical models in that it includes both crop and livestock production, which gives the model the flexibility to choose whether the two activities are optimally nonseparable.
Price policy analysis indicates that the land use allocation is relatively insensitive to changes in commodity prices, i.e., altering commodity-based support payments is insufficient to attain environmental improvements. Several "green" policy instruments are simulated to estimate the cost to producers of reducing environmental damages. Limiting soil erosion with either a regulatory standard or a per unit tax reduces the average return to land by 10%. Shifting current income support payments into a system of payments for conservation land management practices, similar in essence to the Conservation Security Program, cannot attain the same soil erosion reduction with less cost to producers. Overall, the inelastic response of land use practices to commodity prices indicates that targeting the use of productive inputs, as opposed to commodity outputs, may be a more efficient means of attaining environmental improvements.     

ECONOMIC ANALYSIS OF ON-FARM SOLUTIONS TO DRAINAGE PROBLEMS IN IRRIGATED AGRICULTURE

Agricultural production in many semi-arid areas over the world is affected by poor drainage and saline conditions. Optimal agricultural management can be considerably different under these conditions than in locations where these problems do not occur. A long-run steady-state model is developed to analyse several management strategies for a farm with limited natural drainage and no access to off farm facilities. The model is applied to a representative farm in California. Under optimal management, the results suggest relatively small evaporation ponds, a reduction in water application, and little change in cropping patterns. Some drainage reuse is optimal when only variable reuse costs are considered. Returns to land and management are positive in all cases considered and benefits from a free off-farm facility are approximately $260/ha.     

Identifying entry points to improve fertilizer use efficiency in Taihu Basin,China

Overuse of fertilizers in China causes environmental problems and high costs for farmers. In this paper we aim to identify entry points to improve fertilizer use efficiency in Taihu Basin, China. We use stochastic frontier analysis to estimate the technical and fertilizer use efficiency of rice production based on a survey held among 320 households in Wuxi, Zhenjiang and Changzhou, located upstream of Taihu Lake. Subsequently, Tobit model is applied to analyze factors influencing fertilizer use efficiency. The average technical efficiency and fertilizer use efficiency in this area in 2008 were 84.2% and 25.4% respectively. On average, rice production is thus efficient, but fertilizer use efficiency can be substantially improved. The results of the regression analyses explaining fertilizer use efficiency indicate that although extension services have stimulated the use of formula fertilizer in Taihu Basin, the use of formula fertilizer has not (yet) improved fertilizer use efficiency. Environmental awareness on water pollution and on the effect of fertilizers, off-farm income and a positive risk attitude have a significant positive effect on fertilizer use efficiency in Taihu Basin. Possessing a car or truck, labor intensity and the occurrence of disasters, on the other hand, have a significant negative effect on fertilizer use efficiency. Policies aimed at improving fertilizer use efficiency may therefore focus on increasing knowledge on the environment and fertilizer management, improving extension services and encouraging farmers to migrate or work off-farm.