A UNITED STATES Department of Agriculture study just out suggests that conventional chemical-based agriculture will have to adjust dramatically if many present farmlands are not to become wastelands within the next century. Writing in the magazine Nature concerning the study of neighboring farms about 20 miles south of Spokane, Ore., Profs. John P. Reganold and Lloyd F. Elliot and graduate student Yovonne L. Unger have concluded that while organic farming is sustainable into the indefinite future, conventional, chemical-based farming is not.
The study focused on two adjacent winter wheat fields with the same soils, one organically managed since it was first plowed in 1908, the other, similarly managed until 1948, when it was subjected to the increasing use of chemical fertilizers and pesticides.
``Observable differences'' in the rate of erosion on the two farms can be traced to the period when the one farm converted to chemicals, the researchers say. Today, 40 years later, the organically farmed field has six more inches of topsoil than its chemically fertilized neighbor.
In addition the organic field has a much greater water-storage capacity, according to the study; was less likely to form a water-shedding crust; and had ``significantly higher levels of polysaccharides,'' a soil ``glue'' produced by microorganisms which makes for good soil structure.
Most significant, at current rates the highly erosion-prone topsoil on the chemical farm ``will be lost in 50 years,'' according to the study.