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The Daily Journal |
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ENVIRONMENT By Danielle Knight WASHINGTON - Increasing livestock populations in Africa, the Middle East and Asia are placing mounting pressure on deteriorating rangelands, according to researchers. Africa, the Middle East, Central Asia, the northern part of the Indian subcontinent, Mongolia, and most of northern China have lost billions of dollars in livestock production capacity as a result of overstocking land with cattle, sheep and goats, says Lester Brown, president and founder of the Earth Policy Institute, a Washington-based environmental think-tank. ''It will take an enormous effort to stabilise livestock populations at a sustainable level and to restore the world's degraded rangelands,'' says Brown. As a result of growth in human population and increased demand for meat in developing nations, the world's population of cattle has increased from 720 million in 1950 to about 1.5 billion in 2001, according to statistics compiled by FAO.The number of sheep and goats expanded from 1.04 billion to 1.75 billion during the same time period. This increase in livestock production since 1950 has led to severe overgrazing worldwide, according to Christopher Delgado, a senior research fellow a the Washington-based International Food Policy Research Institute. Since mid-century, 20 percent - some 680 million hectares - of global rangeland has been degraded by overgrazing, he says. Overstocking rangeland reduces soil fertility and ultimately the size of the herd that can be sustained, says Brown. Once severely damaged by overgrazing, grasslands are hard to restore, he adds. ''Overgrazing of rangelands initially reduces their productivity but eventually it destroys them, leaving desert,'' says Brown. Herds in nearly all developing countries have come to need more fodder than local rangelands and forage resources can sustainably yield. The number of livestock in Africa often exceeds grasslands capacity by half or more, he says. Some 230 million cattle, 246 million sheep and 175 million goats on the continent are supported almost entirely by grazing, he says. In India, with the world's largest cattle herd, the demand for livestock feed in 2000 was an estimated 700 million tons, while the sustainable supply amounted to just 540 million tons, warns Brown. ''In states with serious land degradation, such as Rajasthan and Karnataka, fodder supplies satisfy only 50-80 percent of needs, leaving large numbers of emaciated, unproductive cattle,'' he says. China faces similar overgrazing problems, especially in the northwest, where there are no land ownership rights and no fences to limit overgrazing, says Brown. As a result of economic reforms in 1978, there has been little incentive for individual families to limit the size of their flocks and herds, so livestock numbers have soared, he argues. In Gonge County in eastern Qinghai Province, for example, grasslands can support an estimated 3.7 million sheep. But, by the end of 1998, the region's flock had reached 5.5 million, resulting in deteriorating land quality and the creation of a new desert, according to Brown. ''The result is fast-deteriorating grassland, desertification, and the formation of sand dunes,'' he says. To further illustrate his argument, Brown points out the difference in livestock populations between China and the United States, which have comparable grazing capacity. While the United States has 98 million head of cattle and 9 million sheep and goats, China has 130 million cattle and 290 heads of sheep and goats, according to FAO statistics. Chinese officials estimate that 2,330 square kilometres of land turn to desert each year. In response to the crisis, the government is considering planting a huge belt of trees that would separate the desert from fertile ground, says Brown. According to a review of desertification that appeared in the 1995 edition of the Journal of Arid Environments, a scientific publication, land degradation is taking a heavy economic toll in lost livestock productivity. In the early stages of overgrazing, the costs show up as lower land productivity. But if the process continues, says the article, it destroys vegetation, leading to soil erosion. Livestock production losses from rangeland degradation exceeded 23 billion dollars annually, says the article. Together, Africa and Asia account for two thirds of the global loss. The annual loss of rangeland productivity has cost Africa seven billion dollars, while Asia lost 8.3 billion dollars. In comparison, North America and South America lost 2.8 billion dollars and 2 billion dollars from production losses, respectively. One of the keys to reducing livestock populations, says Brown, is to spread the practice of feeding crop residues and other left over plant material to livestock that would otherwise be burned for fuel or fertiliser. China has a large potential to increase fodder by feeding corn stalks and wheat and rice straw to cattle and sheep, he says. The world's leading producer of rice and wheat, China annually harvests an estimated 500 million tons of straw, corn stalks, and other crop residues. Feeding crop residues to livestock in the major crop-producing provinces of east central China - Hebei, Shandong, Henan, and Anhui - has already created a so-called Beef Belt where beef output dwarfs that of the northwestern grazing provinces of Inner Mongolia, Qinghai, and Xinjiang, says Brown. Researchers are also working on ways to restore overgrazed rangelands in developing nations. The Syrian-based International Centre for Agricultural Research in the Dry Areas (ICARDA) has developed low-cost techniques to reclaim overgrazed and exhausted rangeland. Scientists with the research institute, for example, have developed a simple implement that slightly depresses the soil in double rows, 20 centimetres apart. The tool then seeds grass in these twin depressions, which follow the contour of the land, enabling them to trap rainwater runoff and restore vegetation. |
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