Des Moines Register
06-03-07
Erosion: Drive to increase corn acres could damage soil
By PERRY BEEMAN
REGISTER STAFF WRITER
Plowing trees and native grasses on land held in conservation to plant more corn
will reverse decades of work to prevent crop-related pollution, scientists say.
State researchers suggest that Iowa farmers will put 500,000 acres now in the
Conservation Reserve Program back into production, as a result of the demand
for corn-based ethanol and rising corn prices.
The federal government created the Conservation Reserve Program in 1985 to
reduce soil erosion, stabilize land prices and control agricultural over-production.
Iowa has 2 million acres currently enrolled.
In more recent years, the program has added more environmental goals. As
farmers bid to retire land from production for 10 to 15 years, the U.S. Department
of Agriculture awards points for projects that could reduce greenhouse gases by
pulling carbon out of the air, benefit wildlife and improve water quality by
reducing soil erosion.
"These are historic changes that have people worried about the environmental
consequences," said Bruce Babcock, director of the Center for Agricultural
and Rural Development at Iowa State University. "We will have more soil
erosion, more chemical runoff and less habitat. ... There is no free lunch."
From 1985 to 1993, the CRP program was credited with saving 694 million tons
of soil per year nationwide.
In fact, 20 pounds of soil washes away for every gallon of ethanol made,
according to Duane Sand, a consultant to the Iowa Natural Heritage Foundation,
a nonprofit conservation and land-preservation group. His soil-loss figure is
based on erosion data from the U.S. Department of Agriculture's National
Resources Inventory, and industry data on corn yields and ethanol production
per bushel.
Research by the Rathbun Rural Water Association has demonstrated that
planting crops on the most erosion-prone ground in the watershed - land now set
aside for conservation - would mean the equivalent of dumping an additional
6,200 dump trucks of silt into Lake Rathbun, according to the Army Corps and
Department of Natural Resources. That erosion would be four times the rate
acceptable for soil-conservation purposes.
Lake Rathbun, located in south-central Iowa near Centerville, is a water source
for 50,000 people and a prime fishing spot. Using that land for crops would
increase the amount of soil and algae-feeding phosphorus running into the lake
by 50 percent, said Marty Braster, the utility's environmental manager.
Additionally, ethanol producers' move toward making more cellulosic ethanol
from cornstalks won't necessarily benefit the environment. Cornstalks help
replenish the soil and sweep heat-trapping carbon dioxide from the sky, said
Spencer Tomb, a biology professor at Kansas State University.
On the other hand, the switch to cellulosic, done right, could be a boon to wildlife
and to water quality, various scientists have reported. Growing switchgrass or
other alternative crops to make ethanol could cut soil erosion. In addition, the
year-round ground cover would reduce greenhouse gases in the atmosphere.