Decision-making in soil conservation: application of a behavioral model to potato farmers in Sri Lanka

Soil erosion is one of the most devastating problems in the upper watershed areas in Sri Lanka. Erosion-prone cultivation of vegetables (especially potatoes) on steep slopes, without soil conservation measures, has become a major problem in the recent past. Soil erosion has significant impacts on on-farm as well as off-farm activities. Although various institutions have launched programs to introduce soil conservation techniques, these have not yielded expected results mainly due to a lack of understanding of the potato farmers’ behavior on investment decisions on soil conservation. Hence the conceptual model on investment decisions on soil conservation was tested in this paper. The analytical results of the generalized least square model indicated the importance of personal and economic, as well as institutional, factors in decision-making in soil conservation. Therefore, obtaining farmer adoption of erosion-control practices will require the use of various implementation tools such as education, subsidies, and technical assistance. Low willingness to invest in soil conservation indicated the necessity for public installation of conservation structures if they are to be widely used in potato farmlands in the upper watersheds in Sri Lanka.     

Economics of Soil Conservation: The Upper Mahaweli Watershed of Sir Lanka

This paper estimates the benefits and costs of soil conservation in the Upper Mahaweli Watershed of Sir Lanka. The costs of soil erosion control include the implementation costs of control measures, while the benefits are reductions in the costs of soil erosion. In contrast to many studies in developed countries, the on‐site benefit of soil erosion control in Sri Lanka is estimated to be greater than the off‐site benefit While a social benefit‐cost analysis demonstrates that it is socially desirable to implement conservation measures, the private financial analyses indicate that it is feasible for individual farmers to adopt the conservation measures. Despite private economic feasibility, programs addressing farmers' reluctance to adopt soil conservation measures may be preferable to public intervention in soil conservation activities when the on‐site benefits are greater than the off‐site benefits.     

On-site economic evaluation of soil conservation practices in Honduras

Factors affecting the cost to the farmer of employing soil erosion reduction strategics are examined for the steep hillsides near Tegucigalpa, Honduras. Linear programming and MOTAD are used to examine these factors. Results indicate that some modest reductions in erosion can be achieved at little cost to the farmer by reorganizing production, switching rotations, and using contour plowing. These modest reductions still lead to extremely high rates of erosion. Sharper reductions may be achieved at progressively higher costs as erosion control structures are constructed and acreage is left fallow. There is a high cost to the farmer of reducing erosion to ‘sustainable’ levels. A consistent tradeoff emerges between levels of soil conservation, income, and risk; erosion reduction efforts lead to lower incomes and higher risk. The analysis of likely benefits to farmers for erosion reduction shows that even under assumptions of very high yield losses from soil erosion, optimal farm plans still lead to high rates of soil loss, implying a need for policies that internalize externalities if off-farm damages are to be minimized.     

Returns to Farm-Level Soil Conservation on Tropical Steep Slopes: The Case of the Eritrean Highlands

This study conducts an economic analysis of investment in simple soil conservation technologies in the highlands of Eritrea. The data used in the analysis were obtained from a farm survey and supplemented with data from secondary sources. Risk analysis techniques are used to take account of the uncertainties regarding the relationship between soil erosion and crop yield. The financial analysis reveals negative net present values (NPV_s) and internal rates of return (IRR_s) below 12 per cent for various slope categories. On the other hand, the economic analysis returns positive NPV_s and IRR_s of over 20 per cent. The results clearly indicate that investment in soil conservation technology may not be a viable short-term proposition from the farmer's point of view and yet the net social benefits are positive. There is a strong case for government to provide incentives for soil conservation in view of the economic benefits.     

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.     

Household adoption behaviour of improved soil conservation: the case of the North Pare and West Usambara Mountains of Tanzania

The mountains in the northeastern part of Tanzania have been experiencing declining soil fertility and severe soil erosion due to increased cultivation and other factors attributed to population pressure. This study gives the main results of an analysis of household adoption behaviour towards the use of improved soil conservation measures. An interdisciplinary analytical framework for analyzing household adoption behaviour is presented. The framework links three components of the adoption decision process: the perception of the erosion problem, the decision to use improved conservation measures and the level of investment or effort devoted to soil conservation among adopters. Data collected from a random sample of 300 heads of households was used to estimate logit models of perception of the erosion problem and of adoption of improved conservation measures, and a Poisson regression model of effort devoted to conservation. The results show that participation in promotional activities of soil and water conservation (SWC) programmes influences the adoption decision process at all three stages. Also, ranking of soil erosion as the priority problem in agricultural production, participation in labour-sharing groups and having off-farm income influence the willingness and ability to use improved soil conservation technologies and the level of soil conservation effort.     

A MICRO-ECONOMIC ANALYSIS OF TEA PRODUCTION USING A SEPARABLE RESTRICTED PROFIT FUNCTION

To derive policy-relevant information, the translog form of a separable restricted profit function was used to model empirically estate tea production in Sri Lanka. Data consisted of 87 observations of prices and quantities for various inputs and outputs from 54 different Sri Lankan tea estates. In different tests, the estimated model respected generally the properties implied by underlying assumptions. Results indicated increasing economies of scale in the factory across the sample and optimal field size to be between 300 and 400 hectares. Amongst estimated short-term elasticities, the supply elasticity of made tea was found to be +0.94.     

美国的土壤保护和启示

美国的土壤侵蚀经过６０年的治理得到了明显的减轻,但还存在一些问题,土壤侵蚀形势依然严峻。６０年来美国开展了大量的土壤侵蚀治理项目,土壤保护经历了由注重减轻田间土壤侵蚀,增加土壤生产力到注重减轻土壤侵蚀对环境影响的转变。这对中国的土壤保护有一定的启示作用。     

经验水蚀预报模型的国内外研究进展

土壤侵蚀预报模型是土壤侵蚀科学研究的重点内容之一,其中,水蚀模型又是土壤侵蚀定量研究的重要方法。国内外对水蚀预报模型已开展了大量的研究,取得了显著的进展和成果,经验水蚀预报模型受到众多学者的普遍关注,推动了该模型的不断完善和发展,对于水蚀预报、水土保持和水土资源持续利用有着重要的意义。论文在梳理大量文献基础上,对国内外水蚀预报模型发展进行了对比分析,以期为经验水蚀预报模型的进一步研究和应用提供参考。     

The estimation of agricultural policy effects on soil erosion—An application for the bio-economic model MODAM

As agricultural policies affect land use, they have effects on the amount of soil erosion in agricultural regions through changes of the economic conditions of agricultural production. Prices of inputs and outputs, regulations and incentives can change, forcing or encouraging farmers to adopt new crop rotations. This paper shows how a bio-economic model can be used to describe and estimate the effects of policies on agricultural production and the risk of soil erosion at the example of a region in North-Eastern Germany. The model uses both an assessment tool that is based on a fuzzy-logic approach for the estimation of soil erosion risk of cropping practices, and a linear programming model, that simulates farmers’ economic behaviour under the assumption of gross margin maximisation being the main goal of farmers’ actions.The analysed policy options were both a targeted and an untargeted incentive programme for reduced tillage, and a restriction option where high erosive crops are not allowed on high erodible field types. The results show that policy changes can have an impact on soil erosion. Furthermore, soil conservation policies are shown to have different levels of efficiency in terms of reduced soil erosion related to the costs of the policy. In the case of this study, a restriction option was more efficient than the incentive options. The results of such simulations can serve as a decision support for the development of soil conservation policies and help to foresee the effects of general changes of agricultural policies.     

Economic benefit and ecological cost of enlarging tea cultivation in subtropical China: Characterizing the trade-off for policy implications

Cash crop expansion has become a global land use issue in recent decades. While the enlarging cash crop cultivation brings promising profitability, it can impair the delivery of various ecosystem services, with a risk of threat to sustainability and human well being. In order to make well-informed land use policy decisions, it requires elaborate efforts to characterize the trade-off between the benefit and cost of cash crop cultivation. This paper focuses on the enlarging tea cultivation in subtropical China, using a case of Anji County. We first monitor tea expansion from 1985 to 2016 based on time-series Landsat imageries, and then analyze the subsequent changes of water conservation service through an in-field survey of soil loss. Monetary approach is finally employed to evaluate the trade-off between economic benefit and ecological cost associated with the growing age of tea plantations. Results show that tea plantations expanded rapidly from 1985 to 2016 in Anji County. Delivery of water conservation service has been significantly impaired by the conversion from natural forests to tea plantations, but it can be gradually improved during the long rotational life cycles of tea plantations. For a given plot (1 ha at moderate slope), in theory, the economic benefit and ecological cost exhibit opposite trend associated the growing age of tea plantations, and an equilibrium point is approximately achieved at the 12-year growing age. In reality, ecological cost exceeds the economic benefit throughout the study period in Anji County. More specifically, the net difference increases from 11575 Yuan in 1985–1469167 Yuan in 2016. It denotes that economic benefit fails to compromise the ecological cost of the enlarging tea cultivation in Anji County. Conflicting land use policies (ecological conservation vs cash cropping promotion) and ‘household contract responsibility’ system should account for the unbalanced relationship between economic benefit and ecological conservation. We finally propose four major options towards the win–win possibilities between economic gain and ecological conservation associated with tea cultivation.     

Adoption of soil conservation practices in Belgium: An examination of the theory of planned behaviour in the agri-environmental domain

Soil erosion is a problem with serious on-site and off-site consequences. There exists a broad series of measures to mitigate soil erosion, unfortunately policy makers observe little voluntary adoption. This paper reports on a study to elicit the factors explaining adoption of soil erosion control practices in Belgium. Following a socio-psychological approach, the theory of planned behaviour (TPB), adoption of cover crops, reduced tillage and buffer strips is evaluated using linear regression techniques. Results show that the most explaining factor is attitude towards the soil conservation practice. The TPB adapted to include perceived control and difficulty appears to provide a suitable framework for evaluating adoption of erosion control measures in Belgium. Future interventions directed at promoting erosion control measures should be directed at changing the attitude of farmers. Further study is, however, required in order to elucidate the cognitive foundations of the negative attitude of a majority of farmers towards the implementation of erosion control practices.     

四川省土壤侵蚀空间分布规律研究

为了摸清四川省土壤侵蚀空间分布情况,依据全国土壤侵蚀分级系统、强度划分体系,利用GIS分析方法对全省土壤侵蚀类型与强度进行了分析。研究结果表明:①土壤侵蚀类型分水蚀、冻融侵蚀和风蚀三类,但侵蚀类型的空间差异明显,水蚀严重区位于川东,冻融侵蚀作用影响区为川西,风蚀影响区为川北一带;②水力侵蚀为土壤侵蚀最主要的类型,影响面积占总面积的87.7%,冻融次之,风蚀影响面积最小;③侵蚀强度分析显示水力侵蚀强度最大,风蚀强度次之,冻融侵蚀对土壤的破坏程度最小;④土壤侵蚀的分布与地貌、海拔、坡度、坡向等地形因素及与人类的活动密切相关。     

Efficiency of U.S. conservation-compliance program

Under the conservation-compliance program, most of the individual producers are forced to cut their soil erosion to 7 t per acre annually irrespective of the marginal cost of controlling soil erosion. In a system where coupons to a ton of soil loss were issued to producers and traded, the marginal cost of controlling soil loss within each soil type and across different soil types would be equalized. An instrumental variable procedure was used to determine the effect of soil erosion on net profits. The results for Iowa show that there is considerable difference in the marginal opportunity cost of controlling soil erosion between soil types. By assigning one ton of erosion to Iowa soil type Downs (5-10% slope) instead of Clarion (2-5% slope), there is a savings of $5.00 per acre for the society as a whole. The tradable coupon system is not only efficient, but will also bring in more land under soil conservation.     

A Note on the Adoption of Soil Conservation Measures in the Northern Province of South Africa

This study attempts to expand the range of explanatory variables used in adoption studies. The results suggest that awareness of soil erosion problems and increases in long-term profit are significant indicators of the probability of adopting silt traps and contour ploughing as methods of soil conservation. Factors such as age, security of land tenure, informal communication, size of land holding and difficulty of adopting a particular technology, do not appear to be significant determinants of the adoption of soil conservation measures.     

Moving up the processing ladder in primary product exports: Sri Lanka's "value-added" tea industry

Governments in many developing countries, influenced by the experience of the East Asian newly industrialized countries, have adopted policies to enhance domestic processing of primary commodities as a tool for accelerating employment growth, export revenues, and development. Sri Lanka has traditionally exported tea in the form of bulk (commodity) teas, but “value‐added” teas such as packaged teas, tea bags, etc., have expanded in recent years. This article examines factors affecting the processing of value‐added tea products in Sri Lanka by modeling export supply behavior. Estimates of the long‐run relationship and short‐run dynamics of export supply are presented and discussed. The price of value‐added tea relative to bulk tea, and industry capacity, are identified as the main determinants of export supply, while exchange rate changes have no discernible effect. The policy implications of the analysis for enhancing further expansion of such value‐added teas are presented. These are of interest for both policy makers and development analysts. In particular, the reasons that undermine the effectiveness of exchange rate policy as an instrument to stimulate value addition of primary products have much relevance for similar developing countries.     

沂蒙山区土壤侵蚀问题及对策

沂蒙山区是淮河流域水土流失最严重的地区;分析了沂蒙山区土壤侵蚀状况,提出了水土保持策略:合理开发利用土地资源;坡地退耕还林,强化水土保持工作;控制人口数量,提高人口素质。     

Estimating the joint effect of multiple soil conservation practices: A case study of smallholder farmers in the Lake Naivasha basin,Kenya

The current study seeks to assess the private benefits associated with multiple soil conservation practices (MSCPs) by estimating the marginal value of crop production that can be attributed to such practices. In areas where land degradation associated with soil erosion causes serious agri-environmental challenges such as loss of soil fertility, siltation and eutrophication, a multiple approach to soil conservation is neccessary. However, notwithstanding efforts to encourage adoption of such practices, their uptake remains generally low. Analysing the effect of MSCPs on crop productivity is one of the ways through which the incentives for soil conservation can be explored. To achieve the stated objective, the current study applied propensity score matching and exogenous switching regression techniques to cross-sectional data collected from a random sample of farm households located in Lake Naivasha basin, Kenya. Results indicate that there is a significant positive effect of implementing multiple soil conservation practices on crop productivity. However, we note that whether the additional benefits will cover the opportunity costs associated with the implementation of these practices will depend on farm specific attributes such as slope and the soil conservation effort. In cases where marginal benefits are not substantial to cover opportunity costs for implementation of soil conservation practices, intrinsic or external incentives could be necessary. Policy interventions could focus on offering technical assistance to farmers in selecting soil conservation practices that are best suited to their local condition.     

Adoption of conservation agriculture in Europe: Lessons of the KASSA project

According to KASSA findings, conservation agriculture is less adopted in Europe compared to other adopting regions and, reduced tillage is more common than no-tillage and cover crops. Currently, it is not popularised and it is less researched. The lack of knowledge on conservation agriculture systems and their management and, the absence of dynamic and effective innovation systems make it difficult and socio-economically risky for European farmers to give up ploughing which is a paradigm rooted in their cultural backgrounds. In Norway and Germany the adoption of conservation agriculture has been encouraged and subsidised in order to mitigate soil erosion. In the other European countries the adoption process seems mainly driven by farmers and, the major driving force has been the cost reduction in machinery, fuel and labour saving. Soil and water conservation concerns did not appear as main drivers in the European farmers’ decision to shift or not to conservation agriculture.The shift of European farmers to conservation agriculture is being achieved through a step-by-step attitude, large scale farms are the most adopters. This adoption trend may grow in the future. Indeed, the need to improve farms’ competitiveness, the market globalization and the steady increase of fuel cost will likely contribute to arouse European farmers’ interest in conservation agriculture as it slashes significantly the production costs.Conservation agriculture is not equally suitable for all the European agroecosystems. The need of soil and water conservation in Europe requires anticipating the ongoing process in order to improve its ecological and socio-economic sustainability. Priority would be to define which regions in Europe are the most suitable for conservation agriculture taking into account climate and soil constraints, length of growing period, water availability and quality, erosion hazards and farming conditions. Policy favouring the use of soil cover and profitable crop rotations as management strategies for weed, pest and diseases control will certainly allow developing and disseminating efficient and acceptable conservation agriculture systems.     

A legal framework with scientific basis for applying the ‘polluter pays principle’ to soil conservation in rural watersheds in Brazil

The “polluter pays principle” (PPP) has been looked at from the perspective of legal values and technical principles, namely of soil science, to evaluate the acceleration of soil erosion and the consequent development of degraded areas in the Uberaba River basin (area: 2419 km²), state of Minas Gerais, Brazil. Having accomplished this goal, the study highlights the importance of PPP for the conservation of soil and development of an ecologically equilibrated environment. The diagnosis of degraded areas was based on the coupling of a Geographic Information System with soil loss, land use conflict and tolerance to soil loss models, and revealed a preoccupying situation because an extension of approximately 905 km² (1/3 of the basin) has been considered in advanced state of degradation potentially causing environmental damage (e.g., decline of soil fertility and hence crop production, negative impacts of soil particles export on stream and lake water quality and biodiversity of riverine ecosystems). Facing this problem, a legal framework standing on doctrinaire principles, federal laws and the Brazilian Constitution has been proposed whereby the protagonists of soil degradation are called to assume responsibility as well as the costs of repairing this negative condition. Although the study has been carried out on a specific country under pre-defined settings, the rationale behind the proposals can easily be transposed to other scenarios because the scientific methods on which soil degradation has been defined and mapped are generally applicable, while the suggested legal values are currently applied to many regions on the planet.