|Livestock to 2020 - The Next Food Revolution. 2020 Vision for Food, Agriculture, and the Environment. Discussion Paper 28. (IFPRI, 1999, 79 p.)|
Rapidly increasing livestock production can cause serious damage to the environment, but it can also be harmonious with or even beneficial to the environment when appropriate types and levels of production are in place. 11 Technological progress can further reduce damaging effects while increasing output. This chapter will identify the environmental problems that are now or likely to become the most severe and the policies that exacerbate these problems. It will also identify technologies and policies that can enhance the environmental sustainability of livestock production as the Livestock Revolution unfolds.
11 This chapter draws on Steinfeld, de Haan, and Blackburn (1997) and de Haan, Steinfeld, and Blackburn (1997).
Historically, livestock have played a critical role in the process of agricultural intensification. Livestock recycle nutrients on the farm, produce valuable output from land that is not suitable for sustained crop production, and provide energy and capital for successful farm operations. The integration of livestock and crop operations is still the main avenue for sustainable intensification of agriculture in many regions of the developing world. This is especially true in semiarid and subhumid savanna areas receiving 600 to 1,200 millimeters of annual rainfall. Much of the interior of West, East, and Southern Africa, northeast Brazil, and much of South Asia belong to this agroclimatic category.
Livestock can help maintain soil fertility in soils lacking adequate organic content or nutrients (Ehui et al. 1998). Adding manure to the soil increases the nutrient retention capacity (or cation-exchange capacity), improves the soils physical condition by increasing its water-holding capacity, and improves soil structure. Animal manure also helps maintain or create a better climate for micro flora and fauna in soils. Grazing animals improve soil cover by dispersing seeds, controlling shrub growth, breaking up soil crusts, and removing bio-mass that otherwise might be fuel for brush fires. These activities stimulate grass tillering and improve seed germination, and thus improve land quality and vegetation growth.
Livestock enable farmers in the resource-poor areas of developing countries to allocate plant nutrients across time and space. Land that cannot sustain crop production can be used for grazing to produce manure that can make other land more productive. Grazing livestock can accelerate transformation of nutrients in crop byproducts to fertilizer, speeding the process of land recovery between crops.
Large parts of the developing world, especially in subhumid Africa, are only now beginning to gain the benefits of farming that mixes crops and livestock. As disease constraints are removed, large livestock animals can be integrated into crop operations, providing farm power and manure. In other parts of the world, such as Asia, high cropping and land-use intensities have been sustained over centuries by integrating crop and livestock activities. Livestock continue to be kept for manure and power in these areas, but food production is becoming more prominent with increasing commercialization.
Mixed livestock and crop farming takes on a different form in the more intensified production systems in both developed and developing countries. Crop and livestock operations are integrated into a local system where waste from each operation is processed and transported to become a cheap input for the other. Regionwide integration of livestock and crop operations emerges fairly soon in mixed farming. Small-scale rural infrastructure, such as feeder roads and light motorized or animal transport, facilitate this integration. In more intensive industrial farming systems, the potential for overloading fields with nutrients from farm manure becomes a problem.
Environmental Problems in the Low-Intensity Livestock Systems of Developing Countries
Traditional, low-intensity livestock production methods remain in many regions of the world. Production levels in these systems are determined by locally available resources. Increased demand pressure can push these systems to produce beyond their capacity. This can bring them into conflict with the environment, necessitating changes in traditional practices to reduce damage.
Livestock graze on about 26 percent of the worlds land area. Grazing systems in developing regions mainly rely on native grassland and are only partially mixed with crops. These systems usually do not involve inputs from outside the system. Overgrazing can cause soil compaction and erosion, and can decrease soil fertility, organic matter content, and water infiltration and storage. Overgrazing in hilly environments can accelerate erosion.
The United Nations Environment Programme (UNEP) estimates that since 1945 about 680 million hectares, or 20 percent of the worlds grazing lands, have been significantly degraded (Oldeman, Hakkeling, and Sombroek 1991). Recent evidence suggests, however, that grazing systems are more resilient than once thought, even in the worst cases, where drought has extended desert margins. Satellite imagery shows recent vegetation growing in the West African Sahel at the same northern limits where it once grew before the big droughts of the 1970s and 1980s (Tucker, Dregne, and Newcomb 1991).
Arid grazing systems have extremely limited potential for increasing productivity and great potential for suffering lasting damage. Production in these areas has adapted continuously to highly variable rainfall and feed availability (Behnke, Scoones, and Kerven 1993). Where irrigation or crop production have interfered with livestock resources and movement patterns, ecologically sound systems often have been disrupted. Populations have become sedentary around water points in many cases. The resulting overgrazing and land degradation have threatened the livelihood of pastoral communities.
Flexibility and mobility are essential for achieving sustainable rangeland use in arid areas. Unfortunately, both were seriously impaired in the past by policies that settled pastoralists and attempted to regulate stocking rates from above rather than in consultation with stock raisers. Well-intentioned changes often disrupt traditional systems and sometimes make them unsustainable. For example, new water points induce settlement of large animal and human populations in dry areas. They also make possible year-round grazing instead of allowing stocking levels to fluctuate so that they are low during the dry season. The resulting overload of animals on the range severely degrades grazing resources around the new source of water.
Semiarid zones can sustain more intensive agriculture than arid zones, making possible greater human and livestock populations. Crop encroachment on pastures, deforestation through fuelwood collection, and overgrazing of remaining pastures can then ensue. Crop encroachment on marginal land not only exposes the soil directly to the erosive effects of winds and heavy rains, but it hampers the flexibility of animal movement by obliterating passages between wet- and dry-season grazing areas. Drought emergency programs that hand out subsidized concentrate feed further contribute to range degradation by enabling too many animals to be maintained on the range and preventing natural regeneration of the range vegetation after drought. These feed subsidies increasingly have become an entitlement for pastoralists, especially in North Africa and the Middle East.
Human population pressure is a key contributor to environmental degradation in many areas where livestock are kept. When institutional failure allows people to extract private goods (livestock production) from public goods (common rangeland) without limit, the degradation is even greater. The situation is aggravated further when stock numbers can be kept high at all times because of water development and local cropping in previously pastoral areas. These well-intentioned but ecologically harmful policies often explain why degradation tends to be more severe in semiarid zones than in arid rangelands.
Tropical rainforests cover about 720 million hectares and contain approximately 50 percent of the worlds biodiversity. More than 200 million hectares of tropical rainforest have been lost since 1950. Contributing factors include ranching, crop cultivation, and forest exploitation. Ranching-associated deforestation has been linked to the loss of some unique plant and animal species in South and Central America, the worlds richest source of biodiversity. In Central America the area under pasture has increased from 3.5 million to 9.5 million hectares since 1950, and cattle populations have more than doubled from 4.2 million to 9.6 million head (Kaimonitz 1995).
Clearing forest and savanna to establish pastures in humid areas causes soil nutrients to leach out rapidly under high rainfall and high temperatures. Weeds soon displace grasses and artificial pastures can only be sustained for a period of up to 10 years. More than 50 percent of the pasture areas in the Amazon are now ungrazed fallow, with a significant portion being abandoned because of degradation. Natural regeneration of forests is difficult, especially when the cleared areas are large.
Policies that make titling of land easy and provide financial incentives for large ranches have been the main reasons for ranch-induced deforestation (Kaimonitz 1995). In the late 1960s and 1970s, Brazil subsidized agricultural loans and beef exports, playing an important role in ranch expansion. These policies have now been phased out and investment in large ranches by absentee owners has declined, and so has the rate of deforestation. In Central America in the 1980s rainforests disappeared at an annual rate of 430,000 hectares per year. In 1990-94 that rate was 320,000 hectares annually. The lesson of the 1960s and 1970s is that subsidizing horizontal expansion of livestock production can cause great environmental damage and create disincentives for intensification.
Increasingly evident in the Amazon today are small crop farmers who switch their cleared-forest fields over to livestock grazing only after the soil nutrients necessary to raise crops have been expended (Faminow and Vosti 1998). How these farmers will survive on land that is increasingly degraded is uncertain. No clear alternatives exist.
In many regions farm sizes may shrink because of population pressure, urban encroachment, and subdivision among heirs. Expanding farm operations into communal or new land under these conditions often leads to deforestation or overgrazing. As communal grazing and new land become increasingly scarce, whole farming systems may lose their livestock component. First to go are large stock such as cattle, jeopardizing the nutrient balance in farms along with farmers livelihoods. Reported nutrient deficits range from about 15 kilograms of nitrogen per hectare per year in Mali, to more than 100 kilograms of nitrogen per hectare per year in the highlands of Ethiopia (de Wit, Westra, and Nell 1996).
In virtually all tropical highland areas (for example, the Himalayan hills, African highlands, An-dean countries, and Java) relatively high human population densities are traditionally sustained by complex mixed fanning systems. Further population growth in many of these regions has made it impossible for the traditional mixed systems to survive. Modified mixed smallholder farming is possible when market development permits investment in intensive technologies and inputs.
Environmental Problems of High-Intensity Industrial Livestock Production
As livestock production intensifies, producers adopt technologies that minimize overt direct costs associated with land and labor and take maximum advantage of free access to environmental public goods and capital subsidies. These highly intensive industrial production methods are the rule in developed countries and growing rapidly in importance in the developing world.
Escalating demand for animal products leads to animal concentrations that are out of balance with the waste absorption and feed supply capacity of available land. High concentrations of animals close to human agglomerations often cause enormous pollution problems. Large areas of Western Europe (Netherlands, northwestern Germany, Brittany [France], the Italian Po valley), the northeastern United States, and, increasingly, coastal Southeast Asia and large plain areas in China now show enormous nutrient surpluses that range from 200 to more than 1,000 kilograms of nitrogen per hectare per year (Steinfeld, de Haan, and Blackburn 1997).
Globally pig and poultry industries produce 6.9 million tons of nitrogen per year, equivalent to 7 percent of total inorganic nitrogen fertilizer produced in the world. Excess nitrogen and phosphorus leach or run off the land, affecting groundwater quality and damaging aquatic and wetland ecosystems. Tests in Pennsylvania have shown that about 40 percent of the soil samples from mixed dairy and crop farms exhibited excessive phosphorus and potassium levels. Surplus nutrients from saturated soils leach into surface water and pollute the environment (Narrod, Reynnells, and Wells 1994). A similar scenario is unfolding in Brittany, where one in eight districts had soils with nitrate levels of more than 40 milligrams per liter in the 1980s. Now all eight districts report such nitrate levels, which can cause extensive damage to the regions aquatic systems (Brandjes et al. 1995).
Excess concentrations of livestock and livestock waste also produce gases. Some, such as ammonia, remain local. Others, such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) affect the worlds atmosphere by trapping the suns energy and contributing to global warming.
There are three main sources of livestock-related carbon dioxide emissions. First, domesticated animals emit carbon dioxide as part of basic metabolic functioning or respiration, at an estimated level of 2.8 billion metric tons annually. Second, carbon dioxide emissions result from biomass burning, part of which can be attributed to land clearing and bush fires on pasture used to enhance pasture growth. Third, carbon dioxide is released when fossil fuels are consumed for livestock-related manufacturing and transportation.
Livestock and manure management contribute about 16 percent of the global annual production of 550 million tons of methane. Ruminants mainly produce the methane as a by-product of digesting large amounts of grasses and other fibrous feeds. Pigs and poultry emit relatively low amounts of methane because they cannot digest these fibrous feeds. Methane emissions per unit of product are highest when feed quality is low, which is common, especially in the lowland tropics and subtropics of developing countries.
Twenty percent of methane emanating from animal production comes from manure stored under anaerobic conditions, such as in holding ponds (USEPA 1995). The high levels of methane emanating from anaerobic conditions are usually associated with high levels of productivity and intensity and large production units.
Animal manure also produces nitrous oxide, the most damaging greenhouse gas (320 times more so than carbon dioxide). Animal waste contributes about 0.4 million tons of nitrogen per year, or 7 percent of the total global emissions (Bouwman, Batjes, and Bridges 1992).
The feed requirements of expanding meat and milk production exceed what can be sustained by traditional feed resources such as grazing land and crop by-products. Increasingly the world livestock sector resorts to external inputs, notably high-energy feed such as cereals and oilcakes. Roughage is decreasing in importance as feed and being replaced by cereal and agro-industrial by-products. A corresponding shift toward producing monogastric animals, mainly poultry and pigs, is taking place. While ruminant meat accounted for 54 percent of total meat production in the developing countries in 1970 (FAO 1995a), it accounted for 35 percent in the early 1990s. This species shift is driven in part by the better conversion rates for concentrate feeds offered by monogastric animals.
Feedcrops differ in their pesticide needs and propensity to deplete soil moisture, water, and nutrients. In general, cereal crops (maize in particular) have the potential to cause greater environmental damage than other crops. Cereals require heavy fertilizer and pesticide use and a great deal of water and offer poor ground cover in the early stages of plant development. Legumes, such as soybeans and pulses, generally have the least potential for damage. Maize and wheat deplete nitrates and phosphates the most, while cassava and sweet potatoes deplete the most soil nutrients.
The Environmental Challenge
Industrial livestock production is rapidly springing up close to urban centers in developing countries, because of weak infrastructure, high transport costs, and weak regulation. Like many cities in East and Southern Africa, Dar-es-Salaam, the capital of Tanzania, now has 20,000 dairy cows kept within the city limits. Urban piggeries are increasingly common in Asia, especially coastal China. Large-scale poultry operations are found in periurban areas throughout the developing world.
Industrial and intensive mixed farming systems present the most severe environmental challenge in the livestock sector. These systems have often benefited from policy distortions and the absence of regulations or their lack of enforcement. The regulatory vacuum has often given this type of production a competitive edge over land-based systems. Furthermore, some policies have misdirected resource use and encouraged the development of technologies that are inefficient outside the distorted context. Many developing countries not only provide direct subsidies for feed but also for energy and capital, which constitute some of the major direct costs of industrial production. Economywide policies that offer subsidies for energy and credit often end up favoring industrial production over less-intensive mixed farming and grazing.
Technology can offer solutions to many environmental problems, especially under industrial conditions. But most policy frameworks enable the cheap supply of animal products at the expense of the environment. Self-sufficiency in animal products and continuous supply of high-value food commodities to urban populations are often the overriding policy objectives, particularly in developing countries.
In the developed world the pollution of land, water, and air has raised acute awareness of the environmental problems associated with industrial livestock production. In many cases this has triggered the establishment of policies and regulatory measures that address these problems. Developing countries, on the other hand, typically exhibit an absence of appropriate and enforceable regulations, together with a surge in demand and a lack of effective political expression of concern about growing environmental and health hazards.
Concerns about the long-term productivity of natural resources, including land, water, air, and biodiversity, will not be reflected in market prices unless governments and international organizations define and establish mechanisms to reflect the present and future value of natural resources. Institutions that provide regulatory frameworks need to be developed, local groups need to be empowered, and a legal authority that implements environmental policies needs to be established or reinforced. Prices should be adjusted through taxation to correct for uncharged environmental costs and encourage efficient resource use. Appropriate technological change, the key to solving environmental problems, must be facilitated by government support.