U.S. RARC

Farming Systems Trial

In 1981, we began to study the transition process that occurs when converting from conventional to organic farming. Corn/soybean production was selected as the focus because huge tracts of land, particularly in the Midwest, are devoted to the production of these crops for animal feed. The FST is now one of the longest running experiments designed specifically to study organic cropping systems. Scientists from around the world come to the Research Center to see this famous experiment. The FSTŐs three cropping systems were designed to represent three distinct farming operations:

No synthetic fertilizers and/or pesticides (including herbicides) are used in the organic systems. Instead, biological processes and cultural practices are substituted for chemical inputs and farm-generated inputs are emphasized.

Organic with animals.In this system it is assumed the farmer raises livestock. The animal-based system raises some crops for feed and uses manure as a nitrogen source for corn. The diversified five-year crop rotation includes corn grain, soybeans, oats or wheat, red clover/grass hay, and corn silage.

Organic, legume-based cash grain.This system features a diversified rotation but has no animal component. The system operates under two constraints: 1) a cash grain crop must be produced every year, and 2) legume green manure crops are the primary nitrogen source for corn and small grains. Weed control in both organic systems is done with cultivation, relay cropping, and crop rotation. As with the other organic system, no fertilizer nitrogen or pesticides are applied.

Conventional cash grain. This system represents a conventional corn-soybean rotation with herbicide, insecticide, and fertilizer applied according to current state extension recommendations. While we donŐt like putting chemicals on our land, we do it in order to compare the organic systems to a system that uses the standard agricultural practices that have been proven to produce high yields.

Results and Current Activities

Our results from the first 14 years show that comparable yields can be obtained without the use of chemical pesticides or fertilizers. Corn, which is the most demanding crop in terms of nutrients, suffered a 25% yield reduction during the first four years but had yields comparable to the conventional system in subsequent years. For this reason, transition from conventional input farming to organic farming is much easier when the process begins with a soybean crop or small grain overseeded with a legume.

Yields are highly variable from year-to-year because of climatic variability. During drought years, all corn yields are reduced because of insufficient water. However, we have noticed that yields in the organic corn are not reduced as much as the conventional corn, suggesting that the organic systems may be more resistant to drought-stress.

The FST is entering its 15th field season this year and is at a crossroads where cropping history, combined with previously collected information, can yield a wealth of knowledge that will be essential in defining soil health and identifying the linkage between soil health and crop nutritional value. We have a unique opportunity to study two well-defined food-production systems that are clearly diverging in terms of soil organic matter levels and overall soil quality. While research in the FST has demonstrated only a small net increase in overall soil organic matter in the organic systems and a small decrease in the conventional system, dramatic differences in soil organic matter quality are evident, and we believe these differences in the organic matter quality account for improvements in soil tilth observed in the organically managed soils.

Some of the findings in these plots contradict established ideas about the principal factors controlling soil organic matter quality. We are poised to answer many fundamental questions about the effects of agricultural management practices on the basic processes that we think contribute to maintaining healthy soil. This also represents a prime opportunity to investigate the effects of these differences in soil organic matter on crop health and nutritional value. In short, there is no other comparable experimental site in the country. Many of the Soil Health Initiative activities will be carried out in this experimental site. This year we will be publishing the results from the first decade of the experiment in the major U.S. agronomy journal.