Date of Award
Master of Science
William M. Park
Luther Keller, Thomas Klindt
Renewed concern regarding the problem of soil erosion from agricultural land has led to a serious re-evaluation of federal soil erosion control policy in the United States. The objective of reducing off-site water quality impacts of soil erosion has gained in prominence relative to that of maintaining on-site productivity. Recognition that most federal cost sharing supports implementation of best management practices (BMPs) on land with only slight to moderate erosion problems has led to proposals for targeting efforts to more highly erosive land. Cost effectiveness of soil erosion control efforts can be defined in terms of maximizing erosion reduction per dollar of federal expenditure when off-site water quality impact is considered the dominant objective. The purpose of this study was to evaluate (a) the extent to which the cost effectiveness of soil erosion control efforts was or could be increased by targeting to and within a critically eroding area, the North Fork Forked Deer (NFFD) Watershed of West Tennessee. The NFFD Watershed was an excellent case study area due to the severity of its erosion problem and an extensive base of collected data.
A special Agricultural Conservation Program (ACP) water quality project on the NFFD provided 75% cost sharing for application of BMPs sufficient to bring every field's erosion rate down to soil loss tolerance. In Chapter III summarization of the set of BMPs planned under this project was developed so as to be as comparable as possible with the findings of the National Summary Evaluation of the Agricultural Conservation Program, Phase I (NSE-ACP-I). BMPs included were establishment of permanent vegetative cover, improvement of permanent vegetative cover, terraces, diversions, winter cover, critical area treatment and conservation tillage. Comparison on the basis of the distribution of BMPs by pre-practice erosion rate class and cost per ton of erosion reduction indicated that targeting funds to a critical watershed increased cost effectiveness. This was apparently due primarily to the more highly erosive land base in the NFFD Watershed, rather than any targeting accomplished within the context of the project itself. This set of BMPs was viewed too in light of the pre-project situation in terms of acreage in various pre-practice erosion rate classes and compared to the recommended treatment goals in the project application. The conclusion was drawn that significant potential exists for targeting to highly erosive land within a watershed and more cost-effective BMPs in order to increase cost effectiveness.
Based on the development of the equi-marginal principle of cost efficiency for application to the soil erosion control problem at hand in Chapter II, an LP model of the NFFD Watershed was constructed and employed as reported in Chapter IV. The basic LP model had as its objective maximization of erosion reduction subject to a constraint on available cost sharing funds. The activities in the LP model were BMPs applicable to fields on eight farms synthesized to represent the land and owner-operator characteristics in the NFFD Watershed. Deviation of an "optimal" BMP set from the LP model served to emphasize the conclusion regarding potential for targeting to land within watershed and particular BMPs to increase cost effectiveness.
Policy implications outlined in Chapter V included support for further shifting of funds to critical watershed or areas but also the need to re-evaluate particular aspects of the current approach to include BMP implementation within a project or regular county program. The whole-farm requirement may limit cost effectiveness to the extent that treatment of slight erosive fields is mandated in addition to treatment of highly erosive fields. Possible modifications of the voluntary, first come-first served soil loss tolerance, and uniform cost-sharing aspects of the current approach merit consideration to allow for increased cost effectiveness. Of course, concern for the on-site productivity objective of soil erosion control may influence the advisability of some of these possible changes.
Sawyer, David Garland, "An evaluation of targeting as a strategy for attaining objectives of conservation and water quality in the North Fork Forked Deer Watershed. " Master's Thesis, University of Tennessee, 1983.