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7.4 Industrial agriculture, which increases production, comes with environmental impacts

7.4–7.9 Issues

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In the early days of our species, humans lived off the products of natural ecosystems, foraging for nuts, berries, and other wild plant materials, and hunting wild animals, such as mammoths and musk ox. At the end of the last ice age, some 10,000 years ago, a radical shift occurred as human communities began to domesticate food plants: corn and squash in the Americas, wheat and barley in the Middle East, and rice in China. We also began breeding livestock for a variety of purposes, including meat, milk, leather, and wool. As beneficial as such technologies have been to human societies, they have inevitably had an impact on the environment, particularly with the rise of industrial agriculture developed to meet our rapidly growing urban populations.

polyculture The growing of multiple domesticated crops that may be intermixed with useful wild species.

crop rotation A method farmers use to maintain soil fertility and reduce the buildup of pests by rotating crops on two-, three-, or four-year cycles.

monoculture A planting of a single variety of crop, generally over a large area, that creates an attractive target for pests and pathogens of the crop.

At first, humans performed the work of cultivating and harvesting crops with the help of simple tools and animal power. Haphazard gardens near settlements might have included a polyculture of multiple domesticated crops intermixed with useful wild species. With little or no knowledge of soil chemistry, early farmers learned to maintain soil fertility by rotating crops on two-, three-, or four-year cycles; they alternated between grains, which deplete nitrogen, and plants such as legumes, which enrich it. Formal experiments with natural fertilizers (e.g., bat guano and bone meal), which began in the 18th century, soon reduced the need for crop rotation. By the 1920s, most farmers in the United States and Europe were cultivating monocultures, vast fields of single crops, which could be maintained year after year with the application of natural and synthetic fertilizers, along with pesticides. These monocultures also had the benefit of being easily tilled, seeded, fertilized, and harvested using tractors powered by fossil fuels, which vastly decrease the amount of labor required on the farm (Figure 7.10).

A QUEST FOR HIGHER PRODUCTION AND EFFICIENCY REDUCED BIODIVERSITY IN MODERN AGRICULTURE

FIGURE 7.10 The apparent biodiversity in traditional polycultures contrasts sharply with the large tracts of land planted to monocultures in contemporary industrial agriculture.

The gains in production made with industrial agriculture spread to the developing world with the Green Revolution, which was spearheaded by a dedicated plant breeder named Norman Borlaug (Figure 7.11). Working with wheat in Mexico, Borlaug made several thousand crosses between genetic varieties, producing high-yielding strains that could be grown in a wide range of ecological conditions and that were resistant to many diseases that infect wheat. The results were dramatic. In just 25 years, the national average wheat yield in Mexico increased four-fold, from 750 kilograms (1,650 pounds) per hectare to 3,000 kilograms (6,600 pounds) per hectare.

NORMAN BORLAUG SHOWING THE RESULTS OF WHEAT BREEDING EXPERIMENTS, WHICH WERE KEY TO THE GREEN REVOLUTION

FIGURE 7.11 Borlaug’s work at hunger relief drew on early life experiences. His childhood was spent working on his family’s farm in Iowa, where he developed a basic understanding of farming methods and a feel for the problems faced by farmers. His work during the Great Depression brought him in contact with people suffering the ravages of hunger, an experience that motivated him to live a life dedicated to reducing hunger around the world.

(Art Rickerby/The LIFE Picture Collection/Getty Images)

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Although the Green Revolution emphasized the planting of single varieties of wheat and other grains, why did it depend ultimately on biodiversity to make its gains in production possible?

The revolution that Borlaug began in Mexico spread, first to other Latin American countries and, by the 1960s, to India and Pakistan, which were facing famine. In 1970 Borlaug received the Nobel Peace Prize in recognition of his life-saving work there. But because the Green Revolution involved intensive agriculture, with its range of attendant problems (see Figure 7.24, page 207), it has come under criticism. Even Borlaug recognized that one of the ways to continue to increase production, with reduced environmental impact, may be to return, at least partly, to the past, by incorporating crop rotation and a greater diversity of crops into agricultural systems.

Think About It

In the mid-1960s, some scientists were predicting widespread deaths due to famine by the 1970s. Luckily, this did not occur. How did the Green Revolution alter the predicted course of history?
Because predictions of famine made half a century ago did not materialize, is there no cause for concern about future famines?