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close this bookBriefs for Food, Agriculture, and the Environment - 2020 Vision : Brief 1 - 64 (IFPRI)
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View the document2020 BRIEF 1 - AUGUST 1994: ECONOMIC GROWTH AND DEVELOPMENT
View the document2020 BRIEF 2 - AUGUST 1994: WORLD SUPPLY AND DEMAND PROJECTIONS FOR CEREALS, 2020
View the document2020 BRIEF 3 - AUGUST 1994: WORLD PRODUCTION OF CEREALS, 1966-90
View the document2020 BRIEF 4 - AUGUST 1994: SUSTAINABLE FARMING: A POLITICAL GEOGRAPHY
View the document2020 BRIEF 5 - OCTOBER 1994: WORLD POPULATION PROJECTIONS, 2020
View the document2020 BRIEF 6 - OCTOBER 1994: MALNUTRITION AND FOOD INSECURITY PROJECTIONS, 2020
View the document2020 BRIEF 7 - OCTOBER 1994: AGRICULTURAL GROWTH AS A KEY TO POVERTY ALLEVIATION
View the document2020 BRIEF 8 - OCTOBER 1994: CONSERVATION AND ENHANCEMENT OF NATURAL RESOURCES
View the document2020 BRIEF 9 - FEBRUARY 1995: THE ROLE OF AGRICULTURE IN SAVING THE RAIN FOREST
View the document2020 BRIEF 10 - FEBRUARY 1995: A TIME OF PLENTY, A WORLD OF NEED: THE ROLE OF FOOD AID IN 2020
View the document2020 BRIEF 11 - FEBRUARY 1995: MANAGING AGRICULTURAL INTENSIFICATION
View the document2020 BRIEF 12 - FEBRUARY 1995: TRADE LIBERALIZATION AND REGIONAL INTEGRATION: IMPLICATIONS FOR 2020
View the document2020 BRIEF 13 - APRIL 1995: THE POTENTIAL OF TECHNOLOGY TO MEET WORLD FOOD NEEDS IN 2020
View the document2020 BRIEF 14 - APRIL 1995: AN ECOREGIONAL PERSPECTIVE ON MALNUTRITION
View the document2020 BRIEF 15 - APRIL 1995: AGRICULTURAL GROWTH IS THE KEY TO POVERTY ALLEVIATION IN LOW-INCOME DEVELOPING COUNTRIES
View the document2020 BRIEF 16 - APRIL 1995: DECLINING ASSISTANCE TO DEVELOPING-COUNTRY AGRICULTURE: CHANGE OF PARADIGM?
View the document2020 BRIEF 17 - MAY 1995: GENERATING FOOD SECURITY IN THE YEAR 2020: WOMEN AS PRODUCERS, GATEKEEPERS, AND SHOCK ABSORBERS
View the document2020 BRIEF 18 - MAY 1995: BIOPHYSICAL LIMITS TO GLOBAL FOOD PRODUCTION
View the document2020 BRIEF 19 - MAY 1995: CAUSES OF HUNGER
View the document2020 BRIEF 20 - MAY 1995: CHINA AND THE FUTURE GLOBAL FOOD SITUATION
View the document2020 BRIEF 21 - JUNE 1995: DEALING WITH WATER SCARCITY IN THE NEXT CENTURY
View the document2020 BRIEF 22 - JUNE 1995: THE RIGHT TO FOOD: WIDELY ACKNOWLEDGED AND POORLY PROTECTED
View the document2020 BRIEF 23 - JUNE 1995: CEREALS PROSPECTS IN INDIA TO 2020: IMPLICATIONS FOR POLICY
View the document2020 BRIEF 24 - JUNE 1995: REVAMPING AGRICULTURAL R&D
View the document2020 BRIEF 25 - AUGUST 1995: MORE THAN FOOD IS NEEDED TO ACHIEVE GOOD NUTRITION BY 2020
View the document2020 BRIEF 26 - AUGUST 1995: PERSPECTIVES ON EUROPEAN AGRICULTURE IN 2020
View the document2020 BRIEF 27 - AUGUST 1995: NONDEGRADING LAND USE STRATEGIES FOR TROPICAL HILLSIDES
View the document2020 BRIEF 28 - AUGUST 1995: EMPLOYMENT PROGRAMS FOR FOOD SECURITY IN SUB-SAHARAN AFRICA
View the document2020 BRIEF 29 - AUGUST 1995: POVERTY, FOOD SECURITY, AND THE ENVIRONMENT
View the document2020 BRIEF 30 - JANUARY 1996: RISING FOOD PRICES AND FALLING GRAIN STOCKS: SHORT-RUN BLIPS OR NEW TRENDS?
View the document2020 BRIEF 31 - APRIL 1996: MIDDLE EAST WATER CONFLICTS AND DIRECTIONS FOR CONFLICT RESOLUTION
View the document2020 BRIEF 32 - APRIL 1996: THE TRANSITION IN THE CONTRIBUTION OF LIVING AQUATIC RESOURCES TO FOOD SECURITY
View the document2020 BRIEF 33 - JUNE 1996: MANAGING RESOURCES FOR SUSTAINABLE AGRICULTURE IN SOUTH ASIA
View the document2020 BRIEF 34 - JUNE 1996: IMPLEMENTING THE URUGUAY ROUND: INCREASED FOOD PRICE STABILITY BY 2020?
View the document2020 BRIEF 35 - JULY 1996: SOCIOPOLITICAL EFFECTS OF NEW BIOTECHNOLOGIES IN DEVELOPING COUNTRIES
View the document2020 BRIEF 36 - OCTOBER 1996: RUSSIA'S FOOD ECONOMY IN TRANSITION: WHAT DO REFORMS MEAN FOR THE LONG-TERM OUTLOOK?
View the document2020 BRIEF 37 - OCTOBER 1996: UNCOMMON OPPORTUNITIES FOR ACHIEVING SUSTAINABLE FOOD AND NUTRITION SECURITY - An Agenda for Science and Public Policy
View the document2020 BRIEF 38 - OCTOBER 1996: WORLD TRENDS IN FERTILIZER USE AND PROJECTIONS TO 2020
View the document2020 BRIEF 39 - OCTOBER 1996: REDUCING POVERTY AND PROTECTING THE ENVIRONMENT: THE OVERLOOKED POTENTIAL OF LESS-FAVORED LANDS
View the document2020 BRIEF 40 - OCTOBER 1996: POLICIES TO PROMOTE ENVIRONMENTALLY SUSTAINABLE FERTILIZER USE AND SUPPLY TO 2020
View the document2020 BRIEF 41 - DECEMBER 1996: STRUCTURAL CHANGES IN THE DEMAND FOR FOOD IN ASIA
View the document2020 BRIEF 42 - MARCH 1997: AFRICA'S CHANGING AGRICULTURAL DEVELOPMENT STRATEGIES
View the document2020 BRIEF 43 - JUNE 1997: THE POTENTIAL IMPACT OF AIDS ON POPULATION AND ECONOMIC GROWTH RATES
View the document2020 BRIEF 44 - JUNE 1997: LAND DEGRADATION IN THE DEVELOPING WORLD: ISSUES AND POLICY OPTIONS FOR 2020
View the document2020 BRIEF 45 - JUNE 1997: AGRICULTURE, TECHNOLOGICAL CHANGE, AND THE ENVIRONMENT IN LATIN AMERICA: A 2020 PERSPECTIVE
View the document2020 BRIEF 46 - JUNE 1997: AGRICULTURE, TRADE, AND REGIONALISM IN SOUTH ASIA
View the document2020 BRIEF 47 - AUGUST 1997: THE NONFARM SECTOR AND RURAL DEVELOPMENT: REVIEW OF ISSUES AND EVIDENCE
View the document2020 BRIEF 48 - FEBRUARY 1998: CHALLENGES TO THE 2020 VISION FOR LATIN AMERICA: FOOD AND AGRICULTURE SINCE 1970
View the document2020 BRIEF 49 - APRIL 1998: NUTRITION SECURITY IN URBAN AREAS OF LATIN AMERICA
View the document2020 BRIEF 50 - JUNE 1998: FOOD FROM PEACE: BREAKING THE LINKS BETWEEN CONFLICT AND HUNGER
View the document2020 BRIEF 51 - JULY 1998: TECHNOLOGICAL OPPORTUNITIES FOR SUSTAINING WHEAT PRODUCTIVITY GROWTH TOWARD 2020
View the document2020 BRIEF 52 - SEPTEMBER 1998: PEST MANAGEMENT AND FOOD PRODUCTION: LOOKING TO THE FUTURE
View the document2020 BRIEF 53 - OCTOBER 1998: POPULATION GROWTH AND POLICY OPTIONS IN THE DEVELOPING WORLD
View the document2020 BRIEF 54 - OCTOBER 1998: FOSTERING GLOBAL WELL-BEING: A NEW PARADIGM TO REVITALIZE AGRICULTURAL AND RURAL DEVELOPMENT
View the document2020 BRIEF 55 - OCTOBER 1998: THE POTENTIAL OF AGROECOLOGY TO COMBAT HUNGER IN THE DEVELOPING WORLD
View the document2020 RESUMEN No. 56 - OCTUBRE DE 1998: AYUDA A LA AGRICULTURA EN LOS PAÍSES EN DESARROLLO: INVERSIONES EN LA REDUCCIÓN DE LA POBREZA Y NUEVAS OPORTUNIDADES DE EXPORTACIÓN
View the document2020 BRIEF 57 - OCTOBER 1998: ECONOMIC CRISIS IN ASIA: A FUTURE OF DIMINISHING GROWTH AND INCREASING POVERTY?
View the document2020 BRIEF 58 - FEBRUARY 1999: SOIL DEGRADATION: A THREAT TO DEVELOPING-COUNTRY FOOD SECURITY BY 20207
View the document2020 BRIEF 59 - MARCH 1999: AGRICULTURAL GROWTH, POVERTY ALLEVIATION, AND ENVIRONMENTAL SUSTAINABILITY: HAVING IT ALL
View the document2020 BRIEF 60 - MAY 1999: CRITICAL CHOICES FOR CHINA'S AGRICULTURAL POLICY
View the document2020 BRIEF 61 - MAY 1999: LIVESTOCK TO 2020: THE NEXT FOOD REVOLUTION
View the document2020 BRIEF 62 - OCTOBER 1999: NUTRIENT DEPLETION IN THE AGRICULTURAL SOILS OF AFRICA
View the document2020 BRIEF 63 - NOVEMBER 1999: PROSPECTS FOR INDIA'S CEREAL SUPPLY AND DEMAND TO 2020
View the document2020 BRIEF 64 - FEBRUARY 2000: OVERCOMING CHILD MALNUTRITION IN DEVELOPING COUNTRIES: PAST ACHIEVEMENTS AND FUTURE CHOICES
View the document2020 BRIEF 65 - MARCH 2000: COMBINING INTERNAL AND EXTERNAL INPUTS FOR SUSTAINABLE INTENSIFICATION

2020 BRIEF 44 - JUNE 1997: LAND DEGRADATION IN THE DEVELOPING WORLD: ISSUES AND POLICY OPTIONS FOR 2020

Sara J. Scherr and Satya Yadav

Sara J. Scherr is a research fellow in the Environment and Production Technology Division of the International Food Policy Research Institute. Satya Yadav is a research associate in the Department of Agricultural Economics and Rural Sociology at the University of Arkansas.

By the year 2020 land degradation may pose a serious threat to food production and rural livelihoods, particularly in poor and densely populated areas of the developing world. Appropriate policies are required to encourage land-improving investments and better land management if developing countries are to sustainably meet the food needs of their populations.

Land degradation takes a number of forms, including depletion of soil nutrients, salinization, agrochemical pollution, soil erosion, vegetative degradation as a result of overgrazing, and the cutting of forests for farmland. All of these types of degradation cause a decline in the productive capacity of the land, reducing potential yields. Farmers may need to use more inputs such as fertilizer or manure in order to maintain yields, or they may temporarily or permanently abandon some plots. Degradation may also induce farmers to convert land to lower-value uses. For example, farmers may plant cassava, which demands few nutrients, instead of maize, or convert cropland to grazing land.

Farmland degradation can also have important negative effects off the farm, including deposition of eroded soil in streams or behind dams, contamination of drinking water by agrochemicals, and loss of habitat.

Existing estimates of the current global extent and severity of the problem should be considered indicative at best. The Global Land Assessment of Degradation (GLASOD), based only on the impressions of experts, estimates that nearly 2 billion hectares worldwide (22 percent of all cropland, pasture, forest, and woodland) have been degraded since mid-century. Some 3.5 percent of the 2 billion total is estimated to have been degraded so severely that the degradation is reversible only through costly engineering measures, if at all. Just over 10 percent has been moderately degraded, and this degradation is reversible only through major on-farm investments. Of the nearly 1.5 billion hectares in cropland worldwide, about 38 percent is degraded to some degree. Africa and Latin America appear to have the highest proportion of degraded agricultural land, and Asia has the highest proportion of degraded forestland (Figure 1).

Various sources suggest that 5 to 10 million hectares are being lost annually to severe degradation. If this trend continues, 1.4 to 2.8 percent of total cropland, pasture, and forest-land will have been lost by 2020. Declining yields (or increasing input requirements to maintain yields) could be expected over a much larger area. These data are, however, likely to overestimate the problem, as they do not account for the effects of land improvements, which also appear to be widespread.

THE IMPACT ON GLOBAL AGRICULTURAL PRODUCTION

Globally, there are few studies of the impact of degradation on agricultural production. Pierre Crosson, in a 1994 study, analyzed GLASOD results and other data and concluded that there has been a 17 percent cumulative productivity loss over 45 years (1945-90) as a result of degradation. During that same period, growth in global food production and long-term declines in grain prices were unprecedented; clearly other factors offset the effects of degradation on aggregate performance.

A 1995 study by Rattan Lal of the impact in Africa based on field data estimated that yield reductions due to past erosion may range from 2 percent to 40 percent, with a mean of 8.2 percent for the continent and 6.2 percent for Sub-Saharan Africa. If accelerated erosion continues unabated, yield reductions by the year 2020 may be 16.5 percent for the continent and 14.5 percent for Sub-Saharan Africa. Evidence from four Southeast Asian and three Middle Eastern countries indicates a degradation-induced decline in productivity greater than 20 percent.


Figure 1 - Regional land degradation by type of land use, 1945-90

Sources: L. R. Oldeman, Global Extent of Soil Degradation (Wageningen, the Netherlands: International Soil Reference and Information Centre, 1992); L. R. Oldeman, R. T. A. Hakkeling, and W. G. Sombroek, World Map of the Status of Human-Induced Soil Degradation. An Explanatory Note: rev. ed. (Wageningen, the Netherlands: International Soil Reference and Information Centre, and Nairobi: United Nations Environment Programme, 1990).

Note: Degraded land includes slightly, moderately, strongly, and extremely degraded areas.

HOT SPOTS

Declining food supplies from specific regions due to degradation are likely to have only a modest effect on global food supplies, because of the potential for substitution from other producing areas. However, land degradation could have dramatic effects in specific countries and subregions.

Nutrient depletion is predicted by the experts to cause serious problems in the mid-altitude hills of Nepal, in poor soil quality areas of northeastern India and Myanmar now undergoing transition to permanent agriculture, and in areas in northeastern Thailand, where farmers consistently extract more nutrients from the soil than they put in. It is also expected to cause major problems in large areas of Africa under transition to short fallow or permanent cropping, in areas of reduced silt deposits in the Nile delta, in the subhumid Mesoamerican hillsides, and in the semi-arid Andean valleys, northeastern Brazil, and the Caribbean Basin lowlands, where agriculture is undergoing intensification.

Salinization will be a major threat in the irrigation systems of the Indus, Tigris, and Euphrates River basins, in northeastern Thailand and China, in the Nile delta, in northern Mexico, and in the Andean highlands.

Agrochemical pollution is expected to be critical in cotton-producing areas in Turkey, in high-density and coastal areas in East and Southeast Asia, on banana plantations in Central America, in areas of intensive agriculture in Bolivia, and in peri-urban agriculture in Southeast Asia and Mexico City.

Soil erosion will create serious production problems in southeast Nigeria, in Haiti, and on the sloping lands of the Himalayan foothills, southern China, Southeast Asia, and Central America. Major wind erosion problems will develop in West Asia as rangelands are converted to grain production, in the Sahel, in West Africa owing to poor mechanization techniques, in the dry Andean Valley, and in the Brazilian cerrados.

Vegetative degradation of rangelands will accelerate by 2020, as a result of overgrazing and overexploitation of vegetation for fuel, in the trans-Himalayas and in Southern and North Africa. The spread of Imperata grassland areas in Southeast Asia will also contribute to degradation.

Agriculture-induced deforestation by 2020 will threaten critical habitats in parts of Southeast Asia, Madagascar, the humid Amazon, the hillsides and Atlantic lowlands of Central America, the Pacific rain forest of Colombia and Ecuador, and the Chaco region of Latin America.

STRATEGIES TO REDUCE LAND DEGRADATION

Historical and socioeconomic evidence suggests that farmers often respond actively to degradation by modifying their farming systems or practices and through land-improving investments. Unfortunately, no global or even national data are yet available estimating the scale and effects of land improvements (for example, area under terracing or other soil conservation practices), although data collection efforts are beginning.

Although some types of degradation are irreversible, most can be prevented or reversed by, for example, adding nutrients to nutrient-depleted soil, rebuilding topsoil through soil amendments, reestablishing vegetation, or buffering soil acidity. The practicality of rehabilitating degraded landscapes depends on the costs relative to the value of the output or environmental benefits expected.

Despite the lack of quantitative data, it is clear that land-improving investments are creating a number of "bright spots" in the developing world. Agroforestry, community forestry, and afforestation are beginning to have large-scale positive impacts in numerous countries. Conservation farming is spreading widely in countries including Morocco, the Philippines, and Thailand and regionally in East Africa, parts of West Africa, Mesoamerica, and parts of South America. Water management is improving through water-saving irrigation, water harvesting, aquaculture, small-scale irrigation, and saliniza-tion control.

Diversification into higher-value perennial crops is protecting soils in Africa, Asia, and Latin America. Dryland range rehabilitation schemes are showing positive results in Syria and Jordan, Southern Africa, Mexico, and northern Argentina. Farmer incentives for land investment are improving through range cooperatives in Jordan; more favorable property rights in Cambodia, Ethiopia, Laos, and Vietnam; and community-based natural resource management in many areas.

POLICY RECOMMENDATIONS

An effective response to land degradation calls for improving the incentives for farmers to care for their land and improving their access to the knowledge and inputs required for proper care. Based on lessons learned from past successes and failures in managing land degradation, the following policy actions should be considered:

· Increase research and technology development for land management, and improve the spread of information, through widely linked, user-friendly information systems for farmers.

· Promote land-improving investments (for example, building up soil organic matter, planting trees, and installing small-scale irrigation) through technical assistance and new financing arrangements suitable for low-income farmers.

· Encourage long-term land improvements by securing property rights and rights of access to natural resources, particularly for the poor.

· Develop planning systems for sustainable land use that involve key resource user groups.

· Improve the economic environment for fanners by developing market infrastructure, correcting distorted price incentives, and encouraging rural income growth and diversification.

· For marginal regions, encourage more public investment in infrastructure, social services, and agricultural support services.