Showing papers on "Soil conservation published in 1983"

An Economic Model of Soil Conservation

Abstract: By introducing soil depth and soil loss into a simple model of agricultural production, this paper seeks to determine when the private path of erosion differs from the socially optimal path. Considering the depletion of soil only and abstracting from the environmental disruption caused by erosion, the paper argues that under most institutional arrangements the social and private rates of erosion are the same. The paper concludes that public policy should be directed toward reducing erosion only when it leads to significant pollution externalities.

Productivity of soils: Assessing long-term changes due to erosion

Abstract: An approach to evaluating the long-term effects of erosion on the productive potential of the U.S. soil resource base is presented. This approach involves the application of a numerical index method for quantifying productivity to soil and land use data bases compiled by the Soil Conservation Service. The relative productive potential of soil was evaluated in terms of the environment it provides for root growth based upon the soil9s available water capacity, resistance to root growth and development, and adequacy of pH to a depth of 100 centimeters (39.4 inches). The productivity of soils in Major Land Resource Area (MLRA) 105 in Minnesota now and after 25, 50, and 100 years of erosion was calculated using erosion rates reported in the 1977 National Resource Inventory. The results indicated that the weighted average reduction in soil productivity was less than 5 percent for soils in this MLRA, with the greatest reduction occurring on soils having slopes that exceed 6 percent.

Landownership and the Adoption of Minimum Tillage

Abstract: Full-owner operators and landowners with small holdings have lower minimum tillage adoption rates on cultivated cropland than do other landownership groups after accounting for land quality and regional location. Nonfamily corporate structure does not significantly influence the adoption decision. These conclusions about minimum tillage adoption were obtained from a logit model using 7,649 cultivated cropland observations from across the United States. This study indicates that small operating size poses more of an obstacle to minimum tillage adoption than does separation of ownership from farm operation.

What is conservation tillage

Abstract: Confusion exists over the meaning of the term “conservation tillage.” Writers often use the term interchangeably with minimum tillage, reduced tillage, mulch tillage, no-till, and so on. In the most recent edition of the Resource Conservation Glossary (5) alone, there are 16 terms, which if defined loosely, are all some form of conservation tillage. No wonder the general public is confused by the terminology when those of us who work daily in soil conservation speak ourselves in many tongues. Perhaps the term that leads to the most confusion is “minimum tillage.” Minimum tillage is defined by the Resource Conservation Glossary as the minimum soil manipulation necessary for crop production, or meeting tillage requirements under the existing soil and climatic condition. Admittedly, this overused term has been the bellwether for the benefits of good tillage practices over the past 30 or more years. At one time, the term “minimum tillage” was almost synonymous with plow-plant and wheel-track planting in the Corn Belt and stubble mulch tillage in the wheat-growing areas of the Great Plains. Because the definition, at least in the Resource Conservation Glossary , includes no mention of soil and water …

Adopter characteristics and adoption patterns of minimum tillage: Implications for soil conservation programs

Abstract: A population of farmers in three central Iowa watersheds were surveyed on their use of conservation practices. A temporal distribution by date of adoption was created for the farmers for generally applicable conservation practices. Personal, social, and economic characteristics of the farmers were examined relative to time of adoption, and comparisons were made with the characteristics of traditional adopter types. Results show a similarity between adopters of conservation practices and innovative practices in general. Implications for soil conservation programs are discussed.

Productivity Effects of Cropland Erosion in the United States

Abstract: A systematic appraisal of the effects of erosion on productivity of the soil and the costs of producing crops concludes that these effects will remain small The present soil conservation policy of limiting erosion on all soils to no more than five tons per acre per year takes no account of the economic value of the soil in crop production and ignores the issue of the proper timing of erosion control Because of these defects, the current standard is an inadequate guide for individual farmers and for the nation as a whole The authors propose an alternative standard based on the proposition that soil and other agricultural resources should be managed so that future generations will not have to pay more to produce food and fiber than we do now 83 references, 4 figures, 20 tables

Soil conservation and water quality improvement: What farmers think

Abstract: DEBATE continues in the American agricultural community over policy for achieving soil conservation and the reduction of nonpoint-source pollution. This debate is sharpened by the goals to reduce nonpoint-source pollution expressed in such legislation as Section 208 of the Federal Water Pollution Control Act Amendments of 1972, the Clean Water Act of 1977, the Soil and Water Resources Conservation Act of 1977, and the Rural Clean Water Program outlined in the Agricultural Appropriations Act of 1980. “Best management practice” is a term commonly used to identify a practice or system of practices for controlling agricultural nonpoint-source pollution. Technical information on such practices attests to their effectiveness for improving water quality. But adoption of best management practices by farmers has been hampered by differences in perceptions between public officials and farmers as to what factors influence decisions. Most economic modeling studies of soil conservation and water quality issues use linear programming. Such studies assume that a farmer's primary motivation is profmaximization. But, there may be other factors involved in a farmer's adoption of best management practices. Personal valuse and beliefs, neighborhood and social pressures, and traditions may have as much or more …

Runoff curve numbers for conservation tillage

Abstract: Conservation tillage effects on runoff vary. A new set of Soil Conservation Service runoff curve numbers reflect these effects, based on residue cover.

Soil suitability for conservation tillage

Abstract: MECHANICAL application of a conservation tillage system is but one part of the crop production package. The other part involves the soil and whether or not the soil's physical properties will permit use of conservation tillage and maintain crop yields. In the past, standard tillage techniques were altered only on those soils experiencing severe soil losses or other problems. Efforts to conserve soil focused on keeping the soil in place. Tillage techniques that encourage soil conservation have been available to farmers for years. Widespread adaptation of these techniques has not occurred, however, in part because of the uncertainty of crop yields obtained using these systems. Early conservation efforts promoted complete elimination of plowing. These efforts generally proved unsuccessful in maintaining crop yields, but they did reduce soil loss. One system promoted disking as a substitute for moldboard plowing (7). Another, called mulch tillage, used a field cultivator to stir the soil and kill the weeds in preparing the seedbed. The procedure left much of the previous crop residue on the soil surface (3). Present tillage systems are variations of these early efforts (6, 17). Thorough tilling of the soil was once regarded as a necessary agricultural practice on …

Tillage practices for soil and water conservation in the semi-arid zone I. Management of fallow during the rainy season preceding cotton

Abstract: Field and laboratory experiments were conducted on a crusting loess soil in the northern Negev (Israel) with the aim of improving the efficiency of the use of rain by row crops, either in dryland or irrigated farming, and to decrease erosion. The specific objective of the experiments described was to develop methods that enhance infiltration of rainfall during the winter fallow season in an area with a mean annual rainfall of 400 mm which is subject to wide variation. It was found that the traditional tillage system consisting of deep ploughing (35–45 cm) of dry soil in the fall followed by disking, smoothing and ridging is the worst choise as it could result in runoff losses of as much as 60% of the rainfall, accompanied by accelerated erosion. This water loss can be critical to the success of dryland cotton and also determines whether or not a pre-irrigation of about 25% of the total annual water allotment must be given to irrigated cotton. The traditional practice was compared with: deep ploughed land left fallow during the entire rainy season; ridging after subsoiling instead of deep ploughing; subsoiling and ridging carried out in one minimum tillage operation; direct ridging without primary tillage and basin tillage of ridges following either deep ploughing, subsoiling or minimum tillage. This study showed that by far the most effective method for enhancing infiltration and eliminating runoff was the basin tillage system. The method is adaptable both to mechanized farming and to farming based on animal power or manual labour, and its application can ensure success where rainfall is limiting. It was found that laboratory characterization of soil hydraulic properties with a static rainfall simulator allows prediction of runoff on crusting soils. This means that the need for, and the effectiveness of, conservation measures may be estimated using disturbed soil samples, which is quicker and cheaper than field tests.

Soil erosion in the Palouse: An aerial perspective

Abstract: “AN oasis of farmland…where, on the steepest slopes, 30-degree farming goes on.” That is how a recent issue of National Geographic depicted the Palouse region in the Pacific Northwest ( 1 ). Soils of the Palouse are deep, formed in an extensive deposit of loess and shaped by subsequent water erosion ( 11 ). They are the result of a unique climate, which is excellent for production of winter small grain. However, production practices cause severe erosion because the soil is exposed during the season of precipitation. Most precipitation occurs as rain or snow during the winter months, when a third to a half of the cropland is seeded to winter wheat, which, for a variety of reasons, often provides only minimal cover until spring. Rainfall and snowmelt are often added to the soil when there is a shallow, impermeable frost layer. These factors, combined with steep north slopes and the silty loessial soils, cause most of the erosion that occurs in the region ( 5 ). A half century of erosion control Erosion in the Palouse has been thoroughly studied for 50 years. Farming methods to reduce erosion have been recommended since establishment of the Pacific Northwest Soil Conservation Experiment …

SOILEC Simulating the economics of soil conservation

Abstract: SOILEC is a computerized, long-run, physical and economic simulation model designed to serve two purposes (2). First, the model provides a guide for policymakers wishing to set subsidy levels in contracts with farmers to achieve given conservation targets. Second, the model analyzes for farmers the physical and economic trade-offs involved in management decisions to accomplish soil erosion control. SOILEC ( soil conservation economics is an outgrowth and extension of research in the University of Illinois Department of Agricultural Economics ( 4, 5, 6, 7, 8, 9 ), particularly that by K. E. Bost ( 1 ), who developed a model of soil erosion's impacts on soil productivity and farm production costs for 16 representative soils in the state. Much of the research, particularly that of late, has been done under a cooperative agreement with the U.S. Department of Agriculture's Soil Conservation Service (SCS). The primary thrust of the research has been to develop a tool that SCS field staff can use to help farmers in their conservation planning. How SOILEC works SOILEC estimates sheet and rill erosion using the universal soil loss equation (12). The relationship of soil loss to productivity reduction is based on estimates of soil productivity for four erosion phases: uneroded—no topsoil loss; moderately eroded four inches of A horizon remaining; severely eroded—no A horizon remaining; and very severely erodedtopsoil eroded to undesirable underlying material (3). …

Conservation tillage use

Abstract: AMERICAN farmers are changing the ways they till the soil. In the past decade, a shift has occurred from almost complete reliance on the moldboard plow and turning the soil each year to conservation tillage practices that disturb the soil less and leave more residue on the soil surface. Several factors have encouraged farmers to adopt conservation tillage practices. Foremost among these factors have been economic pressures, particularly high fuel prices. More double cropping is occurring also, which requires the use of practices involving less field preparation for seeding the second crop. In addition, government programs have encouraged practices that reduce soil erosion and improve water quality. The only data available that depict changes in tillage practicces nationally are those published by No-till Farmer (5–9) . These data are compiled annually. They come mainly from conservation districts and from state offices of the Soil Conservation Service and are based heavily on observations and judgments about the changes occurring. Procedures no doubt vary from area to area and from year to year. Some definitions Conservation tillage includes both minimum tillage and no-till systems. No-Till Farmer defines these systems, in contrast to conventional tillage, as follows: …

Implementing LESA in Whitman County, Washington

Abstract: In response to criticisms that its land capability classification and land inventory and monitoring systems were of little value to local planners in determining what land should remain in agriculture, the Soil Conservation Service (SCS) in 1981 created LESA, the agricultural Land Evaluation and Site Assessment. The system has been implemented in two counties within each of six states: Florida, Illinois, Maryland, Pennsylvania, Virginia, and Washington. Pilot counties in all other states are now being added to the list. One of the first pilot tests of LESA was in Whitman County, Washington, where local officials have worked closely with state and federal officials to adapt the system to local circumstances. The approach reported here is still being refined and tested. Land evaluation LESA is actually a combination of two separate subsystems: a land evaluation subsystem and a site assessment subsystem. The land evaluation subsystem incorporates four rating systems: land capability classification, land inventory and monitoring, soil productivity, and soil potential. SCS recommends that one of the latter two ratings be used in conjunction with the first two ratings. Soil potential ratings, which are preferred, indicate the relative quality of a soil for a particular agricultural use. These ratings integrate soil …

Soil Erosion Awareness and Use of Conservation Tillage for Water Quality Control

Abstract: Water pollution through loss of topsoil from farmland continues to be a major problem, despite nearly 50 years of providing farmers technical and financial assistance for soil and water conservation. The technology for controlling erosion and water pollution is available, but farmers have been slow in implementing control practices. Past research has shown that farmers tend to be unaware of the seriousness of the erosion problem on their own operations. Using a random sample of farmers from central Iowa, the relationship is examined between awareness of a soil erosion problem and the use of conservation tillage. Results indicate that awareness of a soil erosion problem effects the use of conservation tillage, and that awareness can be enhanced by experiential educational strategies such as the development and implementation of a soil and water conservation plan.

Rainfall erosion indices for canada east of the rocky mountains

Abstract: The use of the universal soil loss equation in Canada to estimate soil loss potential for soil and water conservation planning purposes has been limited by the lack of published rainfall erosion indices and by the arduous procedure generally accepted for determination of these indices. This study was conducted to develop and test relatively simple methods to develop annual rainfall erosion indices and associated seasonal distribution patterns. An approach to the determination of a rainfall-runoff factor to accommodate the effect of winter conditions has also been included. The relatively simple techniques for estimating average annual rainfall erosion indices and seasonal distribution patterns of rainfall erosion have been found to yield comparable values to those determined by more tedious methods. These erosion indices and associated distribution patterns have proven useful for the development of a first approximation of rainfall erosion maps for Canadian locations east of the Rocky Mountains. Key words...

Legumes in conservation tillage systems: A research perspective

Abstract: RENEWED interest in the use of legumes in conservation production systems for soil conservation and nitrogen fixation suggests the identification of (a) current uses of legumes in conservation tillage systems and (b) research required to develop further the technology for using legumes in such systems. With this in mind, 40 scientists participated in a work-planning conference in January 1983 at the University of Nebraska-Lincoln. Purpose of the conference, sponsored by the Agricultural Research Service (ARS), was to assess the potential for using legumes in conservation tillage systems and to identify research needs. This was done in six subject areas: germ plasm; host- Rhizobium relationships; cropping systems and nitrogen cycling; weeds, diseases, and pests; water conservation and use; and soil erosion control. Germ plasm Research currently is limited on development of legume germ plasm for conservation tillage systems. Most work is focused on development of improved forage cultivars for hay and pasture or for grain legumes. Few states have more than one geneticist working full-time on forage legume improvement. Several states have none. But a number of legume cultivars exist that have had little or no evaluation for use other than as a forage crop. Most breeding efforts are to improve productivity, reduce disease and insect losses …