July-August 2002: Volume 57, Number 4
Table of Contents
Features
- Modern Day Roosevelt--restoration of the Hackberry Flats wetlands in southwestern Oklahoma
- How Good is Good Enough? What Information is needed for Agricultural Water Quality Planning and How Can it be Provided Affordably?
Research
- Predicted impact of management changes on soil carbon storage for each cropland region of the conterminous United States
M.D. Eve, M. Sperow, K. Howerton, K. Paustian and R.F. Follett
- The cost of soil erosion to downstream navigation
L.T. Hansen, V.E. Breneman, C.W. Davison, and C.W. Dicken
- Adoption of conservation production systems in two Ohio watersheds: a comparative study1
T. L. Napier and T. Bridges
- Profitability and nutrient losses of alternative manure application strategies with conservation tillage
E. Wang, W. L. Harman, J. R. Williams, and J. M. Sweeten
- Farm economics to support the design of cost-effective BMP programs to improve water quality: nitrogen control in the Neuse River Basin, North Carolina
G.A.A. Wossink and D.L. Osmond
Departments
- Home Front-column written by the Society's executive director
- Viewpoint-guest editorial written by a leading conservation professional
- Raise Your Voice-letters to the editor
- Notebook-new section
- Conservogram-the Soil and Water Conservation Society in Action
Predicted impact of management changes on soil carbon storage for each cropland region of the conterminous United States
(Full text appears in the Journal of Soil and Water Conservation, Vol.57, No. 4)
M.D. Eve, M. Sperow, K. Howerton, K. Paustian and R.F. Follett
ABSTRACT: The exchange of carbon dioxide between the atmosphere, biosphere and pedosphere is an important consideration when assessing agricultural and environmental management or policy decisions and their relationship to climate change. Field experimentation is the best way to gather data, but experimental data are specific to the management, soils and climate that represent the research site. Inadequate field data exist to address all management options across all soil types and climates. We have used the Intergovernmental Panel on Climate Change inventory approach to estimate changes in soil carbon storage resulting from various land use and management options. We generate a regional assessment of the relative impact of implementing changes in agricultural management on soil carbon storage. For each agricultural region of the United States, we present an estimated annual change in soil carbon storage for each management option. Results should prove especially useful in evaluating management options and tradeoffs.
Keywords: Carbon dioxide, carbon sequestration, global warming, IPCC, soil organic carbon, soil quality
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The cost of soil erosion to downstream navigation
(Full text appears in the Journal of Soil and Water Conservation, Vol.57, No. 4)
L.T. Hansen, V.E. Breneman, C.W. Davison, and C.W. Dicken
ABSTRACT: The objective of this work is to estimate how changes in soil conservation affect costs to downstream navigation. Models are developed to account for the hydrology and the subsequent flow of sediment within the conterminous states. The hydrologic models, along with detailed data on the location and costs of dredged harbors and shipping channels, provide an avenue for approximating erosion’s impact on navigation costs. Results indicate that a ton of eroded soil in some areas imposes no costs to navigation, while costs reach $5 per ton in other areas. Costs vary significantly across relatively small geographic areas because some watersheds affect no downstream shipping channels or harbors, while others affect major shipping areas and can have high sediment disposal costs.
Keywords: Dredging, harbors, navigation, sediment costs, shipping channels, soil conservation, soil erosion
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Adoption of conservation production systems in two Ohio watersheds: a comparative study1
(Full text appears in the Journal of Soil and Water Conservation, Vol.57, No. 4)
T. L. Napier and T. Bridges
ABSTRACT: Data were collected from land owner-operators who were managing farms within the Darby Creek watershed and within a selected area in the upper Scioto River watershed in central Ohio during the late winter of 1998 and the summer of 1999. Information was collected to assess the types of agricultural production systems used by farmers within each watershed during the previous growing season. Information about agricultural production systems being used in each watershed was compared to determine if farming practices differed between the two watersheds. Study findings revealed that agricultural production systems employed by farmers within the upper Scioto River watershed were not significantly different from those being used within the Darby Creek watershed. This finding was inconsistent with research expectations derived from the traditional diffusion model. Farmers within the Darby Creek watershed had been expected to report adoption of significantly more conservation production systems because they had been exposed to more extensive conservation programming designed to motivate them to adopt and to use conservation practices. Farmers within the upper Scioto River watershed had been exposed to relatively little conservation programming even though the two watersheds were located approximately 40 miles apart. Study findings strongly suggest that massive human and economic resources employed to motivate land owner-operators to adopt and use conservation production systems within the Darby Creek watershed were not successful in accomplishing that objective.
Keywords: Adoption behavior, conservation, production systems, watershed
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Profitability and nutrient losses of alternative manure application strategies with conservation tillage
(Full text appears in the Journal of Soil and Water Conservation, Vol.57, No. 4)
E. Wang, W. L. Harman, J. R. Williams, and J. M. Sweeten
ABSTRACT: Profitability and nutrient loss in runoff and sediment of alternative manure utilization strategies integrated with conservation tillage in irrigated agriculture were examined for the Tierra Blanca Creek watershed in the central Texas panhandle. Average and maximum nitrogen (N) and phosphorus (P) losses in runoff and long-term accumulations of P in the topsoil were simulated. These factors were considered to be environmental indicators of water and soil quality when applying manure and commercial fertilizers. Costs and profitability of alternative manure management strategies were compared to determine how to best safeguard the environment while maximizing profits. The study found that both objectives could be achieved with the application of N fertilizer combined with a reduced manure rate using conservation tillage to eliminate fallowing. A sensitivity analysis of the price of anhydrous ammonia indicated that a 50% increase would, however, reduce the profitability of this strategy to less than that of the two all-manure utilization strategies.
Keywords: Conservation tillage, economics, environment, manure, net present return, nutrient accumulations, nutrient loss, water quality
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Farm economics to support the design of cost-effective BMP programs to improve water quality: nitrogen control in the Neuse River Basin, North Carolina
(Full text appears in the Journal of Soil and Water Conservation, Vol.57, No. 4)
G.A.A. Wossink and D.L. Osmond
ABSTRACT: This paper shows how farm economics information that is widely available can be used to help guide local resource managers and watershed groups in their efforts to design cost-effective programs to improve water quality. The focus is on the economic elements driving farmer and landowner decisions and how those compare with incentive payments to alter these decisions. The approach is illustrated for the case of Best Management Practices (BMPs) mandated for nitrogen control in the Neuse River Basin in North Carolina. The empirical research shows that the economics of the BMPs are very different for the three regions in the basin as distinguished by physiographic conditions. Economic differences in implementing BMPs should be taken into account by state and federal authorities when they are determining cost-share programs. The research also shows that the cost-share payments offered for grass buffers might not be in line with the relative reduction in nitrogen emission offered by this BMP.
Keywords: Best Management Practices, cost-share payment, crop budgets, economics
