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Science Matters by David Suzuki
Whether you ply the aisles of a hangar-like megamart every week, pick up a few things each day from the corner store or have produce delivered to your door, food is one of our biggest purchases - and one that has a major impact on the natural world.
Think about the sheer weight of the food your family goes through each week. All that food has to be grown and transported, and often processed and transported again, before we pick it up. Each step requires energy and infrastructure in addition to the land, energy, fertilizers, water, pesticides and more needed to grow crops in the first place. Together, these inputs take their toll on the environment through groundwater pollution, oxygen depletion in our coastal waters from agricultural runoff, pesticide accumulation, soil nutrient depletion and other problems.
For consumers, choosing less-processed, locally grown food and organic produce can help reduce this damage. But developing a truly sustainable agricultural system that doesn't degrade our natural resources will require widespread changes in farming practices. This is especially true if we are to feed the extra three billion souls expected to inhabit the earth with us over the next 50 years.
The recent World Summit on Sustainable Development would have been the natural place for a plan to start making such changes. But agricultural initiatives, like most concrete plans at the Summit, were watered down or disappeared entirely. A suggestion by economist Jeffrey Sachs of Columbia University to triple the world budget for agricultural research went nowhere.
That's a terrible shame, because we can do much better. One major problem is inefficiency. Vast amounts of water, for example, are wasted through poor irrigation techniques. Agricultural researchers writing in a recent edition of the science journal Nature point out that existing technologies such as drip and pivot irrigation, as well as adding manure to soil and reducing tillage can all increase irrigation efficiency, without reducing crop yields.
Fertilization efficiency could also be vastly improved. Currently, less than half of the nitrogen fertilizer applied to fields is actually absorbed by crops. Instead, most of it ends up leaching into rivers and lakes. Efficiency could be improved by applying smaller amounts of fertilizer closer to the roots when the crops are best able to absorb it. Crop rotation, multiple cropping and closing the nitrogen loop by applying organic fertilizers such as manure can reduce the need for synthetic fertilizers.
Pesticides too are still used indiscriminately, even though crop rotation, growing two or more crops at the same time, and other methods have been shown to be able to reduce or eliminate the necessity of applying many toxic chemicals. Using these methods would also increase the useful life of many pesticides, because the more a pesticide is used, the faster pests develop resistance to it.
Agricultural trends indicate that over the next 50 years, the greatest impact on the environment from farming will likely come from increased meat consumption. Globally, meat production has increased by 60 per cent over the past four decades. Unfortunately, it is often a terribly inefficient way to produce food because it takes between three and 10 kilograms of grain to produce a kilogram of meat.
Compounding the problem is the continued increase of high-density feedlot-type facilities, which add the burdens of animal waste disposal, antibiotic resistance and a higher incidence of disease to an already inefficient process. The authors of the article in Nature argue that raising animals in pastures is less damaging because the animals eat plants growing there, then fertilize them with their manure. They conclude: “When appropriately stocked and managed, grassland-ruminant ecosystems are an efficient, sustainable method of producing high-quality protein with minimal environmental impacts.”
Agriculture has had perhaps a greater influence on human society than any ther innovation. It's enabled our population to explode and our cultures o flourish. Now, our challenge is to make sure our successes in griculture don't degrade the other natural resources we also depend on.
To discuss this topic with others, visit the discussion forum at www.davidsuzuki.org
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