Showing papers on "Soil conservation published in 1987"

Virginia farmers' soil conservation decisions: an application of tobit analysis

Abstract: tergenerational considerations, and income Using data from a survey of farm operators (Ervin and Ervin; Nowak and Korsching; Lee in two Virginia counties, the authors analyze and Stewart; Forster and Stem). farmers' soil conservation decisions. Results Several issues have not been adequately indicate that financial factors, including in- treated in previous studies. The first is the apcome and debt, are the most important in- propriate model of farmers' conservation befluences on the sample farmers' use of conser- havior. In their conceptual model of the convation practices. Additional factors such as servation decision-making process, Ervin and perception of erosion, education level, off-farm Ervin recognize three components: the peremployment, and tenancy also influence con- ception of an erosion problem, the decision to servation expenditures. Factors influencing adopt conservation practices, and the amount conservation tillage acreage differ from those of soil conservation effort. Previous researchinfluencing expenditures for other conserva- ers have analyzed only one of the three comtion practices. In particular, age and race of ponents or have analyzed the components the operator and on-farm erosion potential are separately. significantly related to the use of conservation A second issue is the consideration of contillage but not other practices. These results servation tillage versus other conservation are discussed in terms of their implications for practices. Previous studies have combined conservation programs.

The Impact of Soil and Fertilizer Phosphorus on the Environment

Abstract: Publisher Summary This chapter describes the impact of soil and fertilizer phosphorus on the environment. Phosphorus in the form of phosphate (P) is essential for plant growth and its application to agricultural land often improves crop production. Production per unit area is increased with fertilizer P. The increased plant cover that is possible with proper use of fertilizer can reduce soil erosion from the cultivated area. Addition of phosphorus to fish ponds may also increase fish production. Potentially toxic chemical elements may be introduced into the food chain by adding P fertilizer to the soil. Increase in the amounts of soluble and particulate P transported in surface runoff have been measured after the application of fertilizer P. Phosphorus losses in surface runoff may be reduced by incorporating fertilizer material into the surface soil, away from the zone of extraction and detachment, and by using conservation or minimum tillage methods to reduce soil erosion. The detachment and transport of particulate phosphorus is also elaborated.

World Agriculture and Soil Erosion

Abstract: A dequate food supplies depend on productive land. Soil erosion is a major environmental problem that threatens world food production (UNEP 1980). Today the human population is greater than ever before, and more people are malnourished (Swaminathan 1983). At present, one billion people are malnourished and the problem is growing rapidly (Latham 1984). Currently 97% of the world's food supply comes from land rather than oceans and other aquatic systems (CEQ 1980). Therefore, the control of soil erosion for a sustainable agricultural system is essential to any program to improve world food security and development. Just at a time when agricultural efforts are focused on increasing crop yields, land degradation is increasing. The dimensions of land destruction

Soil erosion and crop productivity

Abstract: Soil is a natural resource of great importance in agriculture, especially because it provides crops with water, nutrients and rooting space. Nevertheless, soil degradation is accelerating, with negative effects on human health, natural ecosystems and climate change, as well as on the economy. Recently, researchers have estimated soil loss from farmlands at about 6 tonnes per hectare, per year. In this context, the Commission adopted in September 2006, a comprehensive EU strategy specifically dedicated to soil protection.

A small rainfall simulator for the determination of soil erodibility.

Abstract: A small rainfall simulator is described, which can be used in the field as well as in the laboratory for the determination of infiltration and erosion characterisitcs of soils. It is particularly suitable for soil conservation surveys, as it is light to carry and easy to handle in the field. A description is given of a standard procedure for the determination of topsoil erodibilities in the field and some results are presented. The method appears to be highly sensitive to soil properties influencing soil erodibility, such as clay content, organic matter content and soil pH. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Off-Site Costs of Soil Erosion: A Case Study in the Willamette Valley

Abstract: This study attempts to provide relative magnitudes of average and marginal costs of off-site sediment-related costs in Oregon's Willamette Valley. Water treatment; road, river channel, and dam maintenance; and hydroelectric generation are examined. Road maintenance and water treatment are nonnegligible average cost items. These costs should not be interpreted as justification for erosion control as marginal cost estimates for water treatment indicate that controls on the margin would yield roughly one-third the average cost. Erosion can cause both on- and off-site damages. It has been argued that off-site damages impose significant costs upon society (Crosson). Alterations in off-site costs potentially could increase the social benefits of soil conservation activities; however, few studies have quantified the off-site economic costs of erosion and the magnitude of the various possible components of off-site cost (as discussed in Crosson and Brubaker). The major objective of this research is to execute a pilot case study examining a number of off-site items through which soil erosion may impose costs on society, constructing preliminary estimates on the relative magnitude of these costs. The case study region is the Willamette Valley of Oregon. The major objective of the study is to develop an estimate of the total cost arising through a number of items and to quantify the relative magnitude of these items, identifying

Soil loss tolerance: Fact or myth?

Abstract: THE concept of tolerable soil loss, as now applied in soil conservation programs, does not serve the long-term interest of mankind in assuring the indefinite productive capability of cropland. Why? Because soil loss tolerances—T values—presently assigned to cropland soils are based on faulty premises concerning rates of topsoil development and mineral weathering processes. The concept of soil loss tolerance rests upon two assumptions: first, that soil scientists can assess reliably and objectively the maximum rates of soil erosion that can be tolerated and, second, that policymakers can objectively weigh that assessment against countervailing interests or needs, however these may be defined. Both assumptions should be challenged. Short-term political considerations may demand that public policy allow soil resources to degrade, gradually but unceasingly, to a state of agricultural uselessness. But continued support of such a policy must clearly acknowledge the extent and quality of known information about soil development rates under agricultural conditions. Soil loss tolerance values are too important to continue to be based on what amounts to quasi-scientific folklore. The T-value concept The intense nationwide soil conservation movement, initiated in the United States in the 1930s, included a strong quest for practical knowledge …

Soil erosion and water treatment costs

Abstract: The relationship between communities9 water treatment costs and soil erosion is estimated. Twelve communities in Ohio9s Corn Belt were selected for analysis. Independent variables, other than soil erosion, used in the analysis included treatment plant size, storage time of unmated water, and turbidity improvement due to water treatment. Results indicate that a 10% reduction in annual gross soil erosion results in a 4% reduction in annual water treatment costs. For Ohio communities, reduced annual water treatment costs would total $2.7 million, with a 25% reduction in soil erosion.

Land reclamation in iceland

Abstract: Erosion is one of the most severe ecological problems in Iceland. It has been estimated that more than 50%o of the original vegetative cover has been lost since settlement in 874 and active erosion continues to be widespread throughout the country. Since its founding in 1907, the Soil Conservation Service of Iceland (SCS) has emphasized control of wind erosion and reclamation of eroded areas. Methods have primarily involved stabilizing sand dunes with Elymus arenarius and reseeding eroded lands with grasses such as Festuca rubra and Poa pratensis. Approximately 2%o of Iceland has been fenced off by the SCS to exclude livestock grazing from areas experiencing severe erosion. The vegetation has recovered considerably within these protected areas and in other areas where grazing intensity has been reduced. The rate of recovery varies greatly depending on elevation, soil type, proximity to natural seed sources, and reclamation practices.

The Environmental Effects of Conventional and Organic/Biological Farming Systems. I. Soil Erosion, with Special Reference to Britain

Abstract: Soil erosion is a world-wide phenomenon having a serious effect upon many agricultural soils. Until recently it was considered that erosion in Britain was limited to only a few susceptible soils in specific areas. However, the increasing monitoring of soils over the past 20 years has shown that water induced erosion is now a widespread and growing threat to farmland in many parts of Britain. This increase in the incidence of erosion can be directly related to changes that have taken place in agricultural practise in recent decades, with traditional mixed farming systems based on complex rotations being replaced by increasingly intensive and specialised cropping systems. After a brief introduction to the world situation, the review concentrates upon an assessment of soil erosion in Britain; concluding that the threat to the soil is almost entirely due to water and not wind erosion. A detailed assessment of the evidence describing the extent and rates of water- induced erosion is followed by a desc...

Soil productivity, soil conservation and land evaluation

Abstract: ICRAF's main contributions to research related to soils have been a symposium, Soils Research in Agroforestry; a review of soil productivity aspects of agroforestry; a further review of the potential of agroforestry for soil conservation, covering both erosion control and maintenance of fertility; the construction of a computerized model to predict soil changes under agroforestry systems; and a handbook of practical methods of agroforestry for soil and water conservation in dryland Africa In research on land evaluation, an environmental data base has been established, leading to a capacity to obtain information, for environmental conditions similar to those of a given site or area, on publications, multipurpose trees, crops, existing agroforestry systems and current experimental work Land evaluation for agroforestry cannot be achieved merely by synthesis of methods from agriculture and forestry, but will require more data on the performance of agroforestry land utilization types Recognition of problems of environmental degradation has become an integral part of planning for agroforestry research By means of a partial synthesis between land evaluation and diagnosis and design, a procedure of site selection for agroforestry research and development has been established

Physical and Conservation Constraints and Management Components for SAT Alfisols

Abstract: The Alfisols of the semi-arid tropics are well-drained soils, but possess low water-storage capacities. They are, therefore, cropped only during the rainy (monsoon) season. With traditional rainfed farming, the soils are both unproductive and prone to excessive runoff and erosion. Efforts to improve management of these soils for conventional cropping have succeeded in increasing crop yields over traditional management systems, but effective practices for improved soil and water conservation remain to be formulated. This is primarily because of the extreme structural instability of the soils. Physical components of improved management have been subject to many0927 investigations and many promising trends have emerged, but no integrated set of practices can, as yet, be confidently recommended for sustaining agricultural productivity on small farms. In this background paper, evidence primarily from research at ICRISAT is used as a basis for discussion of the physical constraints and the promising developments that have been made in improving the conservation and management of these soils.

Farm level dynamic analysis of soil conservation: an application to the piedmont area of virginia

Abstract: however, these studies did not consider policy A conceptual optimal control theory model implications of their findings relating to soil which considers farm level decision making conservation issues. In addition, the decision with respect to soil management is developed. rules i these studies were not clear cut with A simplified version of the theoretical model is respect to their implications for farm manageapplied to the Piedmont area of Virginia. The ment practices. model includes the productivity impacts of The model presented in this article is an imboth soil erosion and technological progress. provement in both the theoretical and emBoth the theoretical model and its empirical pirical application of control theory to soil application are improvements over previous erosion analysis. The theoretical model is efforts. Results suggest that farmers in the more comprehensive than previous efforts, study area can achieve substantial reductions especially with respect to its treatment of inin soil erosion by adopting alternative farming vestment in soil conservation capital and soil practices. productivity. The empirical model's results can be applied directly at the farm level.

Factors related to adoption of soil conservation practices in the Dominican Republic

Abstract: Data were collected in 1982 from 281 land operators in the Ocoa watershed located in the southwestern portion of the central mountains of the Dominican Republic. The purpose of the study was to determine if factors shown in the United States were predictive of adoption behavior in the Dominican Republic. The findings demonstrated that socioeconomic factors were very poor predictors of adoption of soil erosion control practices as measured in this study. Diffusion-type factors were shown to be relatively good predictors of adoption.

Anatomy, physiology, and psychology of erosion

Abstract: Soil can be considered as a living thing, drawing energy for its continued existence from organic matter added by the green plants on its surface. It competes with other components of the biota for this organic matter and if deprived of a sufficient supply, it goes into decline. This decline is marked by a decrease in the population of soil micro-organisms followed by collapse of the soil components. As the system loses coherence, surface particles become liable to movement by wind or water and the soil is liable to erosion. If the soil is viewed in this way, then the problem of erosion can be approached logically by considering its anatomy, physiology and psychology. Under anatomy the physical features of the Earth's landmass are reviewed, together with the air mass that envelopes it and their relationship to particle transport. Physiology covers the processes that develop soil erosion is considered from the viewpoint that continuous ground cover by green plants would prevent erosion. This view is modified to accept that where the cover is altered or destroyed by other species, then erosion may take place. Psychology attempts to understand why the species most capable of rapid and total removal of vegetative cover, man, does so either collectively or singly around the world. The findings of this last section are based on the work of an IFAS study which questioned farmers on over 10,000 small farms in the tropics and sub-tropics from the Philippines to Peru.

Consideration of risk in soil conservation analysis

Abstract: Farm-level soil conservation decisions with uncertain income are examined. Results from a stochastic economics model show that the variability in farm income due to crop prices, crop yield, weather and farmers9 risk attitudes influence the selection of a soil conservation management system. Public conservation programs can be more effective if they are based on analyses considering uncertainty. Two decision criteria, expected utility maximization and safety-first, were selected to compare the ranking of certain management systems under each criterion.