Building Soils for Better Crops Sustainable Soil Management by Fred Magdoff and Harold Van Es - HTML preview

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introduCtion

energy—as well as the diversion of crops to produce

dry grains, process food products, and transport them

ethanol and biodiesel and other trends—will cause

over long distances. With the price of energy so much

food prices to be higher in the future, resulting in a

greater than just a few years ago, the economics of the

worldwide upsurge in hunger.

“modern” agricultural system may need to be reevaluated.

• Too much nitrogen fertilizer or animal manure

The food we eat and our surface and groundwaters are

sometimes causes high nitrate concentrations in

sometimes contaminated with disease-causing organ-

groundwater. These concentrations can become high

isms and chemicals used in agriculture. Pesticides used to

enough to pose a human health hazard. Many of the

control insects and plant diseases can be found in foods,

biologically rich estuaries and the parts of seas near

animal feeds, groundwater, and surface water running off

river inflows around the world, including the Gulf of

agricultural fields. Farmers and farm workers are at spe-

Mexico, are hypoxic (have low oxygen levels) during

cial risk. Studies have shown higher cancer rates among

late summer months due to nitrogen enrichment from

those who work with or near certain pesticides. Children

agricultural sources.

in areas with significant usage of pesticides are also at

• Phosphate and nitrate in runoff and drainage water

risk of having developmental problems. When considered

enter water bodies and degrade their quality by

together, these inadvertent by-products of agriculture are

stimulating algae growth.

huge. The costs of all these negative effects on wildlife,

• Antibiotics used to fight diseases in farm animals can

natural resources, human health, and biodiversity in

enter the food chain and may be found in the meat we

the United States is estimated at between $6 billion and

eat. Perhaps even more important, their overuse on

$17 billion per year. The general public is increasingly

farms where large numbers of animals are crowded

demanding safe, high-quality food that is produced with-

together has resulted in outbreaks of human illness

out excessive damage to the environment—and many are

from strains of disease-causing bacteria that have

willing to pay a premium to obtain it.

become resistant to many antibiotics.

To add to the problems, farmers are in a perpetual

• Erosion associated with conventional tillage and

struggle to maintain a decent standard of living. As

lack of good rotations degrades our precious soil and,

consolidations and other changes occur in the agriculture

at the same time, causes the silting up of reservoirs,

input (seeds, fertilizers, pesticides, equipment, etc.), food

ponds, and lakes.

processing, and marketing sectors, the farmer’s bargain-

• Soil compaction reduces water infiltration and

ing position weakens. For many years the high cost of

increases runoff, thereby increasing flooding, while

purchased inputs and the low prices of many agricultural

at the same time making soils more drought prone.

commodities, such as wheat, corn, cotton, and milk, caught

• In some parts of the country groundwater is

farmers in a cost-price squeeze that made it hard to run

being used for agriculture faster than nature can

a profitable farm. At the time of writing this edition, the

replenish this invaluable resource. In addition,

prices for many agricultural commodities have recently

water is increasingly diverted for urban growth in

seen sharp increases and then a rapid decrease. On the

dry regions of the country, lessening the amount

other hand, the costs of purchased inputs also increased

available for irrigated agriculture.

greatly but then did not decrease as much as crop prices

The whole modern system of agriculture and food is

did. The wide swings in prices of crops and animal prod-

based on extensive use of fossil fuels—to make and power

ucts have created a lot of stress among farmers.

large field equipment, produce fertilizers and pesticides,

Given these problems, you might wonder if we should

xii

Building SoilS for Better CropS: SuStainaBle Soil ManageMent