Economics of erosion-control and seed-fertilizer technologies for hillside farming in Honduras

With population growth still at very high rates and large-scale commercial farmers and cattle ranchers owning much of the more fertile valley land, small-scale farmers are concentrated on increasingly marginal, steeply sloping hillsides in Central America. The continuing soil erosion and land degradation in these low-input staple crop production hillside farming systems lead many to be pessimistic about increasing the agricultural incomes of these farmers. However, this study shows that the appropriate combination of improved technologies and agricultural policy or alternative production diversification strategies can improve the incomes of small-scale hillside farmers in southern Honduras by over 50%. The technology components considered are stone walls and ditches combined with living tree barriers to prevent erosion of the hillsides, and a package of improved sorghum seed, seed treatment, and modest doses of nitrogenous fertilizer. A whole-farm mathematical programming framework is used to determine the potential farm-level income effects of the soil-conservation and seed-fertilizer technologies. The main conclusion is that erosion-control devices and yield-increasing crop varieties and fertilizer are an effective technology introduction strategy for the erosion-prone hillside landholdings found in many areas of Central America. If policy actions or diversification strategies for disposal of surplus grain are found which are effective in reducing the risk of low income from cereal price reductions in high-production years, adoption of the improved technologies is shown to be profitable for small-scale farmers. Another benefit not explicitly considered would be to slow the very rapid growth of urban poverty in these countries. Sensitivity analysis results indicated that neither risk aversion nor the increased availability of crop land or initial cash have any substantial effects on the predicted adoption level of the improved technologies, or on their income impacts for these farmers.     

Adoption of SWC measures in South Limburg (The Netherlands): Experiences of a water manager

In the loess area of the southern part of Limburg soil erosion is responsible for damage in the agricultural area and the associated runoff leads to flooding of urban areas and deposition of mud on the infrastructure.Since the second half of last century erosion hazards and damage have increased, due to more intensive tillage of the soil. With a general use of artificial fertilizers, organic matter content of the soil dropped to critical levels. Besides that, activities in agriculture like enlargement of fields, use of heavy machinery and activities outside the agricultural area like the extension of the built-up area and infrastructure led to less infiltration and consequently to more runoff. The expected change of the climate – more intensive rain showers – may even aggravate the erosion problem in the future. Moreover, the general policy of protection of the urban areas against flooding is developing to a higher protection level.The public sector is responsible for general policies to control erosion and to bring the damage of flooding back to acceptable levels. The basic principle is to tackle the erosion problem at the source, on the farmer's field with measures among others by the introduction of non-turning-ploughing and mulching and preservation and expansion the area of grassland. At local level, specific erosion control measures and financial arrangements are made. Municipalities are supposed to prepare and guide local level erosion plans, where measures are taken to complement the individual on-farm erosion control measures. Municipalities have to solve small-scale problems (bottlenecks) with local flooding and sedimentation of mud, especially on infrastructure. To prevent flooding the Water Authority has the task to develop the water infrastructure mainly to buffer water and to convey runoff at a safe discharge (grass strips, grassed waterways).In the combat against erosion the farmers and the farmer's organizations took their responsibility. The efforts resulted in 1990 in an Erosion Ordinance (EO) lately revised in 2003. The EO is primarily a responsibility of the farmer's organisations. In 2000 authorities involved in erosion and flood control signed a covenant in which generic and specific interventions were agreed upon to realize in a period of 4 years. Tough the agreed measures are only partly realized in this period, the intentions of the covenant are still valid. In 2003 the farmer organizations introduced in the revised EO a new instrument: the Farm Erosion Management Plan (FEMP) in which a farmer can take its own responsibility to keep erosion risk at an acceptable level and to organize his own farm strategy. By taking enough measures in the FEMP, the farmer gets dispensation of several measures otherwise due to the EO. Farmers can rely on EU-subsidies when applying erosion control measures (cross-compliance). Both the EO and the FEMP are part of the EU Common Agricultural Policy (CAP).In spite of legislation, accepted responsibilities at different levels and financial support (incentives), erosion control interventions do not (yet) cover the whole area and not all stakeholders are equally motivated to implement and maintain the measures. In practice monitoring of the fulfilment of the EO and the FEMP is quite complicated, because of scattered land property, the complexity of the instruments and lack of (trained) controllers. At the moment the Water Authority is evaluating the effectiveness of measures taken by the FEMP in relation to general legislation of the EO.At municipality level several plans to solve the problems at locations where flooding and mud deposition occurs frequently are ready, but lack of funds will postpone execution of some of them.     

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.     

Determination of yield and erosion damage functions using subjectively elicited data: application to smallholder tea in Sri Lanka

Tea has been Sri Lanka's major export earner for several decades. However, soil erosion on tea-producing land has had considerable on-site and off-site effects. This study quantifies soil erosion impacts for smallholder tea farms in Sri Lanka by estimating a yield damage function and an erosion damage function using a subjective elicitation technique. The Mitscherlich-Spillman type of function was found to yield acceptable results. The study indicates that high rates of soil erosion require earlier adoption of soil conservation measures than do low rates of erosion. Sensitivity analysis shows the optimum year to change to a conservation practice is very sensitive to the discount rate but less sensitive to the cost of production and price of tea.     

Awareness and adoption of conservation agriculture in Malawi: what difference can farmer-to-farmer extension make?

Despite the potential of conservation agriculture (CA) for increased crop yields, energy savings, soil erosion control, and water-use efficiency, smallholder farmers in sub-Saharan Africa have been slow to adopt. Farmer-to-farmer extension (F2FE) may have a role to play in overcoming the information access problems and lack of knowledge that may preclude widespread adoption. This study uses data for 180 lead farmers linked to their 455 followers to investigate how F2FE influences awareness and adoption of CA technologies in Malawi. Results from a bivariate probit model for follower farmer awareness and adoption of the three CA principles (minimum soil disturbance, crop residue retention, and crop diversification) reveal four main findings: First, lead farmer motivation increases their effectiveness at diffusing CA practices to their followers. Second, lead farmer familiarity with and adoption of CA both matter to the spread of CA practices, but familiarity appears more important. Third, lead farmers play a more critical role in increasing awareness than adoption of the CA practices. Finally, F2FE is a complement rather than a substitute for other sources of agricultural extension in Malawi's pluralistic extension system and should support but not replace current systems. Research and policy implications are discussed.     

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.     

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。     

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.     

Stochastic Technology, Risk Preferences, and Adoption of Site-Specific Technologies

A model of farmer decision making is developed to determine the extent to which uncertainties about soil fertility and weather affect the value of site-specific technologies (SSTs) using jointly estimated risk and technology parameters. Uncertainty can lead risk-averse farmers to apply more fertilizers and generate more pollution than in the certainty case. Ignoring uncertainty and risk aversion would overestimate the economic and environmental benefits of SSTs and underestimate the subsidy required to induce adoption. Accounting for uncertainties and risk preferences might explain the low observed adoption rates of SSTs. Improving the accuracy of SSTs would increase the incentives for adoption.     

Consumers' Preferences for Nanotechnology in Food Packaging: A Discrete Choice Experiment

We examine consumers' preferences for chickens under different levels of foodborne health risk, animal welfare and pric attributes. We analyse how their preferences vary according to the risk reduction method. Our comparison is between risk reductions achieved by conventional improvements in the meat supply chain system (e.g. more stringent regulations and inspection regimes), and risk reductions achieved by food packaging nanosensors. Our comparison uses a two‐treatment discrete choice experiment in which each treatment sample is only presented with one of the risk reductions: either nanotechnology or conventional methods. We also investigate heterogeneity in preferences for two consumer groups: (i) consumers who usually buy conventional raw, whole chickens, and (ii) consumers who usually buy niche, welfare‐improved chickens, such as free‐range and organic. Our results show evidence of heterogeneity in preferences and willingness‐ to‐pay values of the both consumer groups. We find that consumers, on average, prefer raw, whole chicken with a lower risk of food poisoning, better animal welfare, and lower costs, regardless of the presence of nanosensors. Although consumers in general showed no strong preferences towards or resistance to nanotechnology, those who buy chickens with better animal welfare, on average, showed higher WTP for food risk reduction and animal welfare relative to conventional chicken consumers.     

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.     

Why don't producers adopt best management practices? An analysis of the beef cattle industry

Cattle producers were surveyed to determine their adoption rates and reasons for non‐adoption of 16 best management practices. Potential reasons for non‐adoption included unfamiliarity, non‐applicability, high cost, still considering adoption, and preference not to adopt. The two most commonly cited reasons for non‐adoption were unfamiliarity and non‐applicability of the practice. Results highlight the importance of educational efforts in encouraging adoption, as well as farm type and financial situation of the farmer.     

Asset Pricing in Created Markets

We investigate the applicability of the present-value asset pricing model to fishing quota markets by applying instrumental variable panel data estimation techniques to 15 years of market transactions from New Zealand's individual transferable quota (ITQ) market. In addition to the influence of current fishing rents, we explore the effect of market interest rates, risk, and expected changes in future rents on quota asset prices. The results indicate that quota asset prices are positively related to declines in interest rates, lower levels of risk, expected increases in future fish prices, and expected cost reductions from rationalization under the quota system.     

Regional erosion risk mapping for decision support: A case study from West Africa

Effective soil and water management strategies require regional-scale assessment of erosion risk in order to locate prioritized area of intervention. Our study focuses on the Atacora mountain and surrounding areas (covering more than 18% of the total land area of Republic of Benin) which face a serious erosion threat despite their ecological and economic importance. To appraise the level of soil erosion risk of large area, we rely on the Instituto Nacional para la Conservación de la Naturaleza (ICONA) erosion model and use data from geographic information system (GIS). The erosion risk model requires four main inputs, namely, information on slope, lithofacies, land use and vegetation cover. The slope layer computed from ASTER digital elevation model (DEM) and the lithofacies layer inferred from digital pedogeological map are combined to draw soil erodibility map. To build soil protection map, we use land use/land cover layer extracted from LANDSAT 7 ETM + images in addition to vegetation cover layer derived from MODIS NDVI product. The final erosion risk map (with a resolution of 1 arc second) is obtained by overlapping erodibility and soil protection maps. We find that 21.8%, 58.5%, and 19.5% of the study area presents very low to low, medium, and high to very high level of erosion risk, respectively. Moreover, our findings are aggregated at the district-level (administrative unit). We observe that erosion risk is more acute in Boukoumbe district. Kerou, Kobli and Natitingou districts are mildly affected by erosion risk, while Kouande, Materi, Pehunco, Tanguieta and Toucountouna districts face a low risk. Ultimately, the proposed erosion risk map can help researchers and decision makers design and implement effective soil and water management interventions in the study area.     

The Optimal Length of an Agricultural Carbon Contract

In this paper, we present the economic determinants of the optimal length of a carbon offset contract. We find that because of a declining capacity of the soil to sequester carbon, the optimal length of the carbon contract is finite (the marginal benefit of remaining in the contract is declining over time, whereas marginal opportunity cost is rising). We also explore the effect of varying key parameter values on the optimal length in the contract. If the contract requires the farmer to sequester at a higher rate, the farmer chooses the contract for a shorter length of time, and this may decrease rather than increase social welfare. If society places a higher value on carbon accumulation, the contract is chosen for a longer length of time. Finally, if both the farmer and society have a higher discount rate, the model provides a somewhat surprising result. The overall time in the contract, and benefits from carbon accumulation are higher when the common discount rate is higher.     

Understanding the influence of farmer motivations on changes to soil erosion risk on sites of former serious erosion in the South Downs National Park,UK

Serious soil erosion occurred in the South Downs National Park, southern England in the years 1982–2006 and details of around 400 sites are contained in a database. In 2010 we revisited 85 of the most serious sites where erosion of >10 m³ ha⁻¹ y⁻¹ had been recorded in order to assess land use change and any conservation measures undertaken. At 79% of the sites land use change had resulted in a reduction in the risk of erosion, most notably at 28 sites with a shift to permanent grass from winter cereals. At only 21% of sites was the risk of erosion unchanged. Twenty two farmers responsible for 66 of the sites were interviewed. Land management practices had changed on all of the fields of interest to this study since the time of the serious erosion events, to those which have the potential to lower soil erosion risk. Sixteen interviewees claimed that erosion was a motivating reason for changing their practices, due to either experiencing on or on- and off-farm impacts firsthand (12), having knowledge or suspicion of serious erosion having occurred on their land prior to their management (three), or having no knowledge of any serious erosion on their land but just wanting to reduce overall erosion risk (one). Amongst the main changes reported are changes of land use from winter cereals to grass or to overwinter stubble which have undoubtedly reduced the risk of erosion. However, some changed practices claimed by farmers, such as along-the-contour-working, earlier sowing and the use of rollers may be of little value. Furthermore, deeper analysis of farmers’ motivations regarding changes in land management practices suggests a complex picture in which a range of socio-economic influences come into play over time including financial incentives offered by agri-environmental schemes which were found to be an important driver of change. Future changes in farming economics may therefore undermine the reduction in erosion risk in the longer term.     

Searching for a downward spiral? Soil erosion risk,agro-forest landscape and socioeconomic conditions in Italian local communities

Soil erosion is a common form of land degradation in Europe concentrating on sloping rural areas. Consequences of soil erosion include the alteration of the long-term balance between ecosystem functioning and socio-ecological systems. Although it was hypothesized that rural areas with specific environmental (soil, climate, vegetation) and territorial attributes (economic marginality and poor accessibility) are more exposed to soil erosion risk, less information are available on the spatial link with various socio-spatial, productive, cultural and political attributes of local communities, spanning from unemployment to subsidence agriculture, from quality of life to water management, from poverty to economic backwardness. Taken together, these factors may trigger a downward spiral leading to land degradation. The present study explores, on a municipal scale in Italy, the spatial relationship between an index of soil erosion risk and 133 indicators describing six research domains. Exploratory data analysis based on non-parametric inference, principal components analysis and hierarchical clustering was carried out with the aim to profile municipalities exposed to high risk of soil erosion and to identify a restricted number of factors possibly determining a downward spiral towards soil erosion and land degradation. Results indicate that the socioeconomic profile of risky areas in Italy is characterized by specific rural development attributes and defined productive structure and socio-spatial characteristics representing a possible target for mitigation policies. Multi-factor studies investigating the influence of the local socioeconomic context on soil erosion may contribute to improve the effectiveness of national soil conservation strategies.     

Economic Impacts of Technology,Population Growth And Soil Erosion At Watershed Level: The Case Of the Ginchi in Ethiopia

A dynamic bio‐economic model is used to show that, without technological and policy intervention, soil loss levels, income and nutrition could not be substantially or sustainably improved in a highland area of Ethiopia. Although cash incomes could rise by more than 40% over a twelve‐year planning period, average per ha soil losses could be as high as 31 tonnes per ha. With the adoption of an integrated package of new technologies, however, results show the possibility of an average two‐and‐a‐half‐fold increase in cash incomes and a 28% decline in aggregate erosion levels even with a population growth rate of 2.3%. Moreover, a minimum daily calorie intake of 2000 per adult equivalent could be met from on‐farm production with no significant increases in erosion. However, higher rates of growth in nutritional requirements and population introduce significant strains on the watershed system. From a policy perspective, there is a need for a more secure land tenure policy than currently prevailing to facilitate uptake of the new technology package, and a shift from the current livestock management strategy to one that encourages livestock keeping as a commercial enterprise. It would also imply a shift to a more site‐specific approach to land management.     

Estimating the costs and benefits of soil conservation in Europe

Economics is about problems of choice. In erosion control, both public authorities and private land users are faced with such problems. What is the impact of erosion, both on-site and off-site, and to what extent can this impact be quantified? If we conceptualize this impact in terms of sustainability, how can we compare one type of effect against another? The former question can be answered only by natural scientists, the latter by economists and other social scientists. Weighing different aspects of sustainability requires value judgments, and economists are sometimes accused of having a jaundiced view of reality, wrongly supposing that decisions are based on rationality and denying the importance of emotion.However, let us assume that there is some mileage to be gained out of attempting to estimate the cost of erosion in an economic sense—which consists of converting the various effects into a common denominator: euros. If we can predict the impact of erosion control measures on erosion rates, we can know the benefit of these measures. The cost also needs to be calculated, not in terms of money but in terms of resources expended (which could have been used for other purposes) and in terms of possible negative impacts of erosion control (for instance, increased use of herbicides in reduced-tillage systems).There are important other considerations which economists may study. Firstly, there is the comparison of present versus future costs and benefits: how much can we sacrifice today for higher sustainability tomorrow?Secondly, there is the issue of private versus public costs and benefits: how do the goals of private land users differ from (those of?) the public good, how can this help us to predict land users’ behaviour, and what incentives would be appropriate to make them behave in such a way as to maximize the public good? Thirdly, how do we deal with uncertainty and risk?These problems loomed large in a study to support an extended impact assessment for the EU Soil Thematic Strategy, in 2005. Whereas much research has been done on erosion and its impact, much of this is on a small scale. The extent of the problem on a national, let alone a continental or a global scale, is still poorly known. The paper discusses how these problems were faced, which is not the same as saying they were resolved.     

不同兼业程度农户耕地利用行为及其效率研究——基于甘肃、青海两省部分市县的实证分析

运用农户模型构建兼业对耕地利用行为及其效率的分析框架,在分离性成立的前提下,以农户调研数据为基础,利用分组比较、数据包络等方法分析不同兼业类型农户之间的耕地利用行为和效率的差异。研究结果表明:兼业类型对农户耕地利用方式和行为选择有显著的影响,不同类型农户的投入、管理行为和土地规模存在较大差异。总体来说,兼业农户的资本投入、劳动投入等高于纯农户,在兼业户中兼业户Ⅱ高于兼业户Ⅰ;不同的耕地利用行为又导致了耕地利用效率的差异,在分离性成立的条件下,数据包络分析计算出的技术效率表现为纯农户大于兼业户Ⅰ,且两者均大于兼业户Ⅱ。