Accelerated global population growth is generating ever-increasing pressure on natural resources. The exploitation of resources for economic development, especially since World War II, has led to great degradation of the environment in certain areas of the world. Soil erosion, salinization, deforestation, species extinctions, contaminated water, polluted air, increased atmospheric carbon, potential global warming, and the human suffering that results—all are becoming too obvious and serious to be ignored by passengers in our green spaceship. ×Ö´®6

Over the last four decades, the environmental movement has gained great support in the developed countries, including the United States. In the 1980s, people became concerned about long-term protection of the environment via sustainable use and development, and about incorporating that concern into an overall economic development plan for developing countries. ×Ö´®4

Most of the developed countries in the world, including the United States, have invested significantly to correct past errors and strengthened their efforts to protect and enhance their resource bases. Many developing countries, however, are very much behind in their efforts toward sustainability because they do not have the necessary knowledge, capital, and strength of purpose—for this last must be supported by widespread public concern.

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Sustainable Development

In 1987, the World Commission on Environment and Development defined sustainable development as that which "meets the, needs and aspirations of the present without compromising the ability of future generations to meet their own needs." ×Ö´®3

Sustainable development intersects and interrelates the physical, biological, social, political, institutional and economic spheres. Preservation, protection, and enhancement of natural resources—including soil, water, air, plants and animals—are key items in the physical sphere of sustainable development. ×Ö´®8

Another important objective is to preserve biodiversity, which means far more than the preservation and protection of endangered species and may entail the protection of entire ecosystems. Protecting the gene pools of important agricultural crop plants is a major task of sustainable development. ×Ö´®1

To improve the lot of the rural poor, to reassess the sustainability of "primitive" or indigenous cultures, and further to preserve cultural diversity are primary socialpolitical-institutional objectives of sustainable development. ×Ö´®1

Another key goal of sustainable development is to provide technical and financial assistance to less developed countries, regions, and sectors and thus to promote longterm, transgenerational economic benefits. ×Ö´®6

Soil and Water Conservation

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Controlling Soil Erosion. Key activities in controlling soil erosion include: use of sustainable cropping practices such as crop rotation systems, conservation tillage systems, strip cropping, and contour cropping; establishment of grass and trees as ground cover and of windbreaks and shelterbelts; construction of terraces, grass waterways, checkdams, irrigation canals, ponds, and watershed protection systems.

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Many success stories of applying soil erosion control in developed countries and some developing countries have been printed in international reports and journals. In the United States, a vigorous and consistent erosion control program has been established since 1935 under the leadership of the Soil Conservation Service. The latest U.S. National Resource Inventory (1987) shows that 37.3 percent of U.S. cropland is adequately protected against erosion, as is 44 percent of pastureland, 25.5 percent of rangeland, 28.7 percent of grazed forest land, 46.3 percent of ungrazed forest land, and 83.3 percent of other land. Nationwide, 38.2 percent of nonfederal rural land is adequately protected.

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Although more than 50 years of erosion control efforts in the United States have brought the average annual water and wind erosion on cropland below 5 tons per acre (3.8 tons per acre of sheet and rill erosion and 3.3 tons per acre of wind erosion in 1987), there are still 123 million acres of U.S. cropland estimated to be highly erodible in 1987. ×Ö´®6

Protecting Water Quality. The soil erosion control practices already mentioned all help to reduce sediment delivery to waterways. Other activities include reduced use of pesticides, herbicides, and nutrients; organic waste management; and special precautions to protect wellhead, filterstrip, and sinkhole areas. The wetland reserve, environmental easement, and integrated farm management programs of the 1990 farm legislation, when implemented, should help to improve the safety of the Nation's food and drinking water. The 1990 farm bill also seeks to encourage sustainable agricultural practices. Protection of wildlife habitat is an important soil and water conservation activity that contributes to sustainable development.

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Increase in Income and Employment ×Ö´®4

One important feature of sustainable development is the generation of income and employment for the economy. The investment in soil and water conservation will increase the level of national expenditure and thus create an effective demand for labor and other economic resources produced in various economic sectors. This tends to generate direct and indirect expansionary effects on an economy. The speed and realization of the chain reactions of the expansionary process in an economy will depend upon the structure of the economy. The resulting output and employment increase will depend on the amount of initial investment and the linkage effects among the sectors of the economy.

SCS Activities ×Ö´®7

Since 1935, the Soil Conservation Service has been providing technical assistance and limited financial assistance to land users in their implementation of soil and water conservation measures. These cover the development and implementation of conservation plans; identification, development and distribution of grass species for soil protection; assistance in watershed planning for flood prevention; technical and financial conservation assistance to the Great Plains area, the part of the United States most vulnerable to wind erosion; development and conservation of rural resources; and reclaiming rural abandoned mine areas.

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SCS also conducts soil surveys, annual snow surveys, and river basin surveys, which serve in part to support its activities in conservation and resource protection. Since 1960, annual expenditure in SCS conservation activities has been maintained at over $600 million in 1982 dollars. The income and employment effects of investing 1 dollar in conservation in the United States are estimated to generate one-third more than the initial investment to the U.S. economy. Thus, investment in soil and water conservation would contribute to economic development of an economy.

Prevention of Productivity Loss

Investment in soil and water conservation maintains the sustain-ability of soil productivity by preventing or at least retarding the loss of soil productivity. Further, it reduces off-site damage and ensuing maintenance cost, and improves safety for humans and other species, thus contributing to the sustainability of the entire ecosystem. ×Ö´®2

The seriousness of erosion's threat to soil productivity can be shown in a report by Walter V.C. Reid, who says, "[Forty] percent of the productive capacity of Guatemala's land has been lost to erosion; in Haiti, the loss has been so great that no top quality soil remains. In Africa, without conservation measures, 16 percent of the rainfed cropland of 1975 will be lost to erosion by the end of this century... As soil productivity declines, the pressure to exploit remaining resources mounts, and further decline in productivity follows. Worldwide, more than half of the forest land cleared annually can be attributed to replacement of degraded agricultural soil." Throughout much of the Tropics, forest land converted to agricultural and livestock uses loses its productivity extremely quickly, in 1 to 3 years.

Using the Erosion-Productivity Impact Calculator (EPIC), a simulation model developed in the U.S. Department of Agriculture to measure the effects of soil erosion on productivity, and data from all major U.S. land resource areas (defined as areas with similar climate and soil regimes), it is found that even under current conditions of erosion control for a 100-year period, at the national level the loss in productivity over the next 100 years is projected to be less than 5 percent. However, a broad, elongated strip along the Pacific coast, which is currently extremely productive, is projected by the model to lose much of its productivity—in one area, more than 60 percent—while nearly all of the eastern half of the country is projected to lose between 0.1 and 9.9 percent, and in some areas considerably more, of its productivity.

Continuous investment in soil conservation nationwide is crucial, particularly in regions that are vulnerable to potential soil loss.

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Recommendations for a Better World ×Ö´®2

Severe global degradation of soil and water resources evoked questions about the eventual sustain-ability of the Earth's entire ecosystem. Soil and water conservation has been effectively practiced by many cultures in many parts of the world throughout human history. Nonetheless, we find that the decline of many cultures was closely associated with the erosion of their resource bases. ×Ö´®7

In recent years, international technical cooperation and assistance have demonstrated that great advances can be achieved in agricultural, forest, and range productivity in all developing countries at extremely low capital costs through soil and water conservation techniques such as conservation tillage, windbreaks, terraces, and contouring; intercropping agroforestry, and use of green and organic fertilizers. Application of these practices certainly could serve as the starting point. However, to make sustainable development an achievable goal, more attention should be paid to projected population growth.

Ideally we should seek to take the following measures: ×Ö´®8

• Make soil and water conservation an ethical imperative in every human culture.
• Focus on the development of an environmental data base, such as soil surveys, water resource inventories, watershed and river basins, species inventory, gene pools, seed banks, water quality data, use of nutrients and chemicals, and natural resource inventory. The data collected should be fully compatible, so that trends can be detected over a period and geographic differences compared. These data should help reveal the seriousness of the resource degradation problems, and highlight the needed areas for action.
• Foster global cooperation and coordination on environmental policies and practices and try to make them at least equally as if not more important than other national policies such as commodity and trade policies. The currently much-talked-about "debt-for-nature swaps" are a good example of creative thinking and public-private cooperation in policy.

The "debt-for-nature swap" is an approach that is being used by environmental groups to buy up foreign debts with privately contributed donations, and to trade the right to collect these debts from the financially troubled debtor countries in exchange for commitments from these debtor countries to acquire parks, protect tropical forests, and conserve environmental resources. "Debt-fornature swaps" have been applied in such countries as Ecuador, Costa Rica, the Philippines, Madagascar, Zambia, the Dominican Republic, and Poland. ×Ö´®3

In 1990, President Bush included debt-for-nature swaps in his "Enterprise for the Americas" initiative, and Congress authorized swaps for some $1.7 billion in third world debts. ×Ö´®3