Feed Crops Harmful to American farmland

Factory farms also harm American farmland through their consumption of massive quantities of feed crops. Consider this: The average cow eats roughly 30 pounds of food each day. ^viii The beef industry raises more than 30 million cows each year. ^ix Some of those cows feed themselves by grazing on pasture, but the vast majority are raised in feedlots, where they eat corn and soybeans. The result: American cropland is pushed hard to produce an extraordinary amount of grain.

In response to this demand, conventional crop producers have adopted intensive growing practices. These methods increase crop yields, but they also damage the soil and throw natural systems out of balance, primarily due to erosion and loss of fertility.

Crop farming is an ”extractive” process, meaning that as plants grow, they take nutrients from the soil and turn it into plant matter. When the plants are harvested, the nutrients leave the soil’s system. Sustainable practices replenish these nutrients, using compost, manure, or “green manures,” which are plants that naturally deposit nutrients in the soil. Instead of replenishing the soil, intensive practices use chemical fertilizers to supply only what is necessary to grow the next round of crops. Chemical fertilizers are not as effective as natural sources of fertility, and are known to cause long-term depletion of organic matter, soil compaction, and degradation of overall soil quality. ^x In 2005, American farmers used more than 22 million tons of chemical fertilizers. ^xi

Tilling is another aspect of farming that has gone out of balance in industrial practice. When land is plowed, old organic matter is turned under the soil in order to plant a new crop. However, when soil is bare it is most susceptible to erosion. ^xii There are many ways to protect against this. Farmers can leave strips of land untilled, to act as a catch for water-borne erosion. Instead of plowing up and down hills, leaving furrows that carry wet soil straight downhill, they can plow with the contours, making furrows that act as tiny retaining walls. And they can grow cover crops in the off-season, whose plants anchor the soil with their roots.

In the drive to produce ever more grain, however, precautions like these are often not taken. Currently, the average rate of soil erosion on US cropland is seven tons per acre per year. ^xiii This is a serious problem, because erosion causes fertile farmland to lose nutrients and water retention ability. Because the first thing to go is precious topsoil, the soil removed by erosion contains about three times more nutrients and 1.5 to five times more organic matter than that which remains behind. ^xiv The National Sustainable Agriculture Information Service writes that erosion is the single greatest threat to soil productivity in the United States.

origin: http://www.sustainabletable.org/issues/environment/