Posted on 9-5-2003

Organics Is Economic
May 6, 2003, Minnesota Farm Guide

Corn and soybean yields were only minimally reduced when organic production
practices were utilized in a University of Minnesota
research project.

The organic practices were compared with conventional production practices.
After factoring in production costs, net returns between the two production
strategies were equivalent, says Paul Porter, a U of M agronomist. Over 80
percent of corn and soybeans produced in the United States is grown in the
Midwest -- the vast majority with conventional production practices in a
corn-soybean rotation requiring annual synthetic fertilizer and pesticide
application. This corn-soybean rotation is practiced on over 100 million acres.

Organic production practices, in compliance with standards defined by the
United States Department of Agriculture's National Organic Program (NOP),
offer an alternative production system to conventional practices. The
study of the influence of rotation length on yield of corn and soybean when
grown utilizing organic and conventional production practices is published
in the March-April, 2003 issue of "Agronomy Journal," a publication of the
American Society of Agronomy. Porter is a co-author of the article. The
study was conducted at two Minnesota locations from 1989 to 1999.
Scientists evaluated a two-year corn-soybean rotation and a four-year
corn-soybean-oat/alfalfa-alfalfa rotation under conventional and organic
management and production strategies. The analysis of yield data began in
1993, after the first complete cycle of the four-year rotation had
occurred. From 1993 through 1999, corn yields from the conventional
two-year rotation averaged 143 and 139 bushels per acre at the two
locations, while corn grown in the organic four-year rotation averaged nine
percent and seven percent less, respectively. During the same time frame,
soybeans grown in the conventional two-year rotation averaged 43.1 and 40.7
bushels per acre, while organically produced soybeans averaged 19 percent
and 16 percent less, respectively.Weed control was a major factor for the
reduced yields in the organic production system, Porter says. The larger
yield reduction from organically produced soybeans relative to corn was
associated with increased weed pressure in the soybean crop because of its
placement in the rotation sequence. While there was a reduction in both
corn and soybean yields in the four-year organic strategy compared with the
two-year conventional strategy, the organic strategy had lower production
costs than the conventional strategy. Consequently, net returns for the two
strategies were equivalent, without taking organic price premiums into
account. "These results won't surprise producers who are successfully
using organic production systems," Porter says. "But they will probably be
met with skepticism by many in the agri-chemical business who make their
livelihood from the sale of synthetic fertilizer and pesticides."
Conventionally produced soybeans were more responsive than conventionally
produced corn to the expanded rotation length, Porter says. Whereas
conventionally grown soybeans in the four-year rotation yielded from three
to six percent more than soybeans grown in the two-year rotation,
conventionally grown corn in the four-year rotation yielded the same to
four percent less than corn grown in the two-year rotation.

These results suggest conventional soybean yields would be increased when
grown in a longer rotation than the commonly practiced corn-soybean
rotation, Porter says.