Posted by & filed under Consumerism, Livestock, Soil Erosion & Contamination, Water Contaminaton & Loss.

by Lester R. Brown, Earth Policy Institute


Photo copyright © Craig Mackintosh

After the earth was created, soil formed slowly over geological time from the weathering of rocks. It began to support early plant life, which protected and enriched it until it became the topsoil that sustains the diversity of plants and animals we know today. Now the world’s ever-growing herds of cattle, sheep, and goats are converting vast stretches of grassland to desert.

One indicator that helps us assess grassland health is changes in the goat population relative to those of sheep and cattle. As grasslands deteriorate, grass is typically replaced by desert shrubs. In such a degraded environment, cattle and sheep do not fare well. But goats—being particularly hardy ruminants—forage on the shrubs. Goats are especially hard on the soil because their sharp hoofs pulverize the protective crust of soil that is formed by rainfall and that naturally checks wind erosion. Between 1970 and 2009, the world’s cattle population increased by 28 percent and the number of sheep stayed relatively static. Meanwhile, goat herds more than doubled. 

Growth in goat populations is particularly dramatic in some developing countries. While cattle herds in Pakistan doubled between 1961 and 2009 and the number of sheep nearly tripled, the goat population grew more than sixfold and is now roughly equal to that of the cattle and sheep populations combined. These livestock have grazed the countryside bare of its rainfall-retaining vegetation, contributing to the massive flooding that ravaged Pakistan in the summer of 2010. 

A giant dustbowl is now forming south of the Sahara in Africa’s Sahel region, thanks in part to overgrazing. Nigeria, Africa’s most populous country, reports losing 867,000 acres of rangeland and cropland to desertification each year. As human and livestock populations grow, herders and farmers compete for an ever smaller amount of land for each person and animal. The goat population in particular has skyrocketed as the soil has eroded. If Nigeria’s human population and livestock herds continue growing as they are today, the associated land degradation will eventually undermine herding and farming. 

A second giant dustbowl is developing in northern and western China, western Mongolia, and central Asia. After economic reforms in 1978 shifted the responsibility for farming from large, state-organized production teams to individual farm families, China’s livestock populations spiraled upward. The number of goats continues to grow as the land is stripped of vegetation and winds help remove the soil to convert rangelands into desert. 

We can contrast the situation in China with that in the United States, which has a comparable grazing capacity. While the two countries have similar numbers of cattle, the United States’ combined sheep and goat population of 9 million is minute compared with China’s 281 million. 

Unfortunately, all kinds of livestock degrade soils by removing vegetation and trampling the ground. Livestock rotation, mixed crop-livestock farming, and other sustainable agricultural practices can reduce soil erosion, raise cropland productivity, and lead to higher soil carbon content and soil moisture. In some situations, small numbers of livestock can be kept in restricted areas and forage can be brought to them, as in India’s cooperative dairy model. But in the end, the only viable way to eliminate overgrazing on the earth’s rangelands is to balance the size of flocks and herds with nature’s capacity for regrowth. 


Photo copyright © Craig Mackintosh

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9 Responses to “Growing Goat Herds Signal Global Grassland Decline”

  1. JBob

    Informative graphs, but a scatter-brained interpretation of them. What is his point? Why do some areas suffer land degradation and others don’t? I’m sure an analysis of private property rangeland vs commons would shed much more light on the subject.

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  2. Evan Young

    The statement that “all kinds of livestock degrade soils by removing vegetation and trampling the ground” is just plain false and is a paradigm that needs to be buried. The effect of livestock on soils is a question of management not the simple existence of them. We need to change our management of animals, not reduce their numbers. Please follow the links posted on Holistic Management to understand the soil building power of livestock.

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  3. Arian I.

    I agree with Mr. Young. Buffalo roaming the North American Great Plains is one reason why this region is nowadays one of the world’s great agricultural regions. Tens of thousands of years of accumulated buffalo poop is a big contribution♪

    And there is a project in the State of Vermont that uses livestock to assist topsoil formation.
    http://www.wholesystemsdesign.com/rapid-topsoil-formation

    That is being done in a temperate climate. I don’t know how it would work out in a tropical climate, but I imagine a higher initial biomass input would be necessary, due to the accelerated nutrient cycle.

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  4. John

    I too stumbled on the comment about all livestock degrading soil but in the context of the article its fairly clear what the author meant – overstocking of any kind of livestock will lead to environmental degradation.

    Despite that I enjoyed the article and thought the graphs were a simple easy way of getting the message across. I certainly had not quite realised just how much livestock populations had grown internationall.

    As an aside I’m always impressed by Craig’s photos, so often they are the reason why I get an article. Keep up the great work.

    Reply
  5. Craig Mackintosh PRI Editor

    I fully agree with the need to adjust our management of animals to be more holistic and in tune with what were once more natural grazing cycles. I put the post above up not to devalue livestock, but really just to give people an idea of population trends. This population data urges us to take holistic management of livestock far more seriously than we presently are.

    I would also go one step further to say that, holistically managed or not, I think there are limits to growth that also need to be kept in mind. Holistic Management relies on land having time to heal (buffaloes came in vast herds, but they didn’t stay in one place), and that cannot occur when populations levels are excessive. As China and other nations move up the food chain, land that was providing people with a great deal of food in the form of fruit and vegetables is now providing much less food in the form of meat (with an approximate 7:1 loss ratio). This is having significant impacts (see also) on our geopolitical situation, not to mention the environmental and social costs.

    Thanks for your comment John.

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  6. warren seal

    Great article Lester. Anyone who has grazed cattle intensely knows that the grass must rest or it will become overgrazed and die. A good approximate formulae is graze 1 week, rest 3 weeks–depending on soil moisture and animal intensity. Intense sheep grazing is harder on grass as they graze so close to the ground; goats are hardest of all as they graze everything down to the roots. It seems in the Sahel that they put the animals to pasture and leave them there. No wonder the pastures have turned barren.

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  7. Wayne Richards

    I have to agree with Mr. Brown that grazing degrades the crop land. The poop animals leave can only be a fraction of the grass they have eaten. The difference is, of course, the amount of heat they give off. That heat, wafting off to who knows where, has been provided but not reclaimed by the grassland, which is now the poorer by exactly that quantity. That’s just good ol’ Newton.

    I mostly agree with him also about the compression of the soil as the animals walk over it. Unfortunately, my scientific mind is somewhat warped at this point because I cannot erase from it the glorious line by Stephen Spender: “The force that through the green fuze drives the flower”.

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  8. Evan Young

    @ Warren Seal. I think you are on the right track, but rest periods have no formula, they are entirely dependent on climate, season, pasture species, number of animals, fertility, goals and more. Rest periods could be up to 3 months, as usual the answer is ‘It depends”.
    @Wayne Richards, given that grass species get most of their mass from the air and not from the soil is doesn’t matter that weight of manure is less that the amount of plants consumed. The manure is also heavy with microbes and other goodies that all benefit the soil. As for soil compression, this again all comes back to adequate rest periods. Properly functioning grasslands sequester more “greenhouse gases” than is emitted by the animals ranging on them. Also, like forests they have a moderating effect on the climate.

    Reply

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