Suchergebnisse

"How to restore and maintain the productivity of the soil is the most important phase of the conservation problem. We are no longer a new nation. We have deluded ourselves with the idea that we have unbounded resources in land, in forests, in mineral wealth. We have been prodigal in the utilization of these resources. We must pay the penalty of this prodigality. In many of our older communities soil fertility has been reduced below the point of profitable production. Nation-wide effort at the present time, through federal and state agency, is directed toward the restoration of fertility in these localities. On the prairies of the West fertility is beginning to wane. In order that our heritage in the prairie country may not follow the descent of the East and the South, it is necessary that intelligent and vigorous effort be made to farm correctly. We must cease abusing the soil. The renting of land on short leases for the purpose of growing grain for market is one of the surest means of reducing the productive power of the soil. The domestic animal, with well-managed pastures and rational systems of crop rotation, is preeminently adapted to the development of permanent systems of profitable farming. Landowners must realize this and must take steps to improve renting methods by stocking farms with a full complement of domestic animals, where the renter is not able to do this for himself, and by giving longer leases, whereby the renter may reap the reward of intelligent management."--Introduction (p.5). ; Cover title. ; Disposal of land by the government -- Importance of cheap and abundant food -- Steps in agricultural development -- Difficulties in changing types of farming -- Exploitive farming too long continued -- Decrease in population and abandonment of land in the older states -- The present situation -- Conditions in older countries -- The solution of the problem -- Effect of live stock on soil fertility -- Effect of legumes -- Dependence on our own resources -- Examples of successful farming. ; "How to restore and maintain the productivity of the soil is the most important phase of the conservation problem. We are no longer a new nation. We have deluded ourselves with the idea that we have unbounded resources in land, in forests, in mineral wealth. We have been prodigal in the utilization of these resources. We must pay the penalty of this prodigality. In many of our older communities soil fertility has been reduced below the point of profitable production. Nation-wide effort at the present time, through federal and state agency, is directed toward the restoration of fertility in these localities. On the prairies of the West fertility is beginning to wane. In order that our heritage in the prairie country may not follow the descent of the East and the South, it is necessary that intelligent and vigorous effort be made to farm correctly. We must cease abusing the soil. The renting of land on short leases for the purpose of growing grain for market is one of the surest means of reducing the productive power of the soil. The domestic animal, with well-managed pastures and rational systems of crop rotation, is preeminently adapted to the development of permanent systems of profitable farming. Landowners must realize this and must take steps to improve renting methods by stocking farms with a full complement of domestic animals, where the renter is not able to do this for himself, and by giving longer leases, whereby the renter may reap the reward of intelligent management."--Introduction (p.5). ; Mode of access: Internet.

Land degradation is a major cause of poverty in rural areas of developing countries. In many areas, farming populations have experienced a decline in real income due to demographic, economic, social, and environmental changes. Land degradation is a result of several factors of both physical and socio-economic nature. The immediate consequence of land degradation is reduced crop yield followed by economic decline and social stress. The integrated process of land degradation and increased poverty has been referred to as the "downhill spiral of unsustainability" leading to the "poverty trap" (Greenland et al., 1994). Soil erosion is one facet of land degradation that affects the physical and chemical properties of soils. The physical parameters are primarily organic matter content, structure, texture, bulk density, infiltration rate, rooting depth, and water-holding capacity. Changes in chemical parameters are largely a function of changes in physical composition. The consequences of topsoil erosion on soil productivity depends on the depth and quality of the topsoil relative to the subsoil. In areas where the topsoil is acid and the organic matter content is initially low, surface erosion may, in fact, increase crop yields due to the exposure of a more favourable subsoil. Tigray is the northern region of Ethiopia (Fig. 1). It consists of several agro-climatic zones, determined mainly by altitude, rainfall and temperature. The eastern parts of the region, including the Danakil depression, are extremely dry. The highlands of central Tigray vary in altitude from about 1 300 m to over 3 000 m in the highland areas of Adwa. Most parts of Degua Tembien and parts of Abergelle have rolling to hilly high plateaus. Most of the areas between 1 500 and 2 300 m have an annual rainfall of less than 900 mm. Rainfall in the area is unpredictable, and it is quite common to observe both water logging and drought during one cropping season. The population density in the region is relatively high, and small units of land are extensively cultivated by subsistence farmers. The severity of soil erosion in the Tigray region and in Ethiopia in general, is the result of the mountainous and hilly topography, torrential rainfall, and low degree of vegetational cover. According to Hamilton (1977), deforestation started already 2 000 years ago. In many parts of Tigray, soil erosion has made cultivation of old farmland impossible. Farmers have been forced to constantly cultivate new and more marginal areas. The objective of this presentation is to review soil erosion and conservation research as well as conservation efforts made in Tigray. We have included both traditional measures and activities promoted by non-government organizations (NGO's) and government projects. Main emphasis is placed on stone terracing and stone bunds since these are the most widely used soil conservation measures in the region. Relatively limited research has been made in Tigray. We have therefore included some important findings from other parts of the Ethiopian highlands for comparison.

Reprint of Journal paper no.1861, Ia. agricultural experiment station project 1085.

El artículo muestra la importancia de desarrollar prácticas agrícolas de tipo conservacionista toda vez que tales prácticas tienen efectos positivos, no solo sobre el grado de sostenibilidad de la producción agrícola sino también sobre los ingresos de los productores. La erosión de los suelos se plantea como un problema real para mantener los niveles de producción agrícola. En términos generales, la erosión se presenta como una externalidad negativa en el sentido de que su efecto de mediano y largo plazo recae sobre el bienestar de agentes no involucrados en el proceso de producción. Sin embargo, los productores directos también se ven afectados por que la productividad de la tierra disminuye y por tanto los beneficios asociados a la producción se reducen en el tiempo. Dos acciones complementarias para contrarrestar los efectos de la erosión y hacer una asignación eficiente de los recursos se proponen en este artículo. La primera es el uso de tecnologías apropiadas y la segunda es considerar la erosión como un costo de producción y, por esa vía internalizar el daño causado a la tierra.