The overall purpose of this research project is to provide demonstrations of and more information about practical alternative and sustainable cropping systems for farmers in Iowa. These cropping systems include oilseed, cereal, and perennial legume species uncommon to current Iowa crop rotation, which is primarily dependent on two species, corn and soybean. Improving farmer economic stability and reducing the negative ecological impacts of current Iowa farming practices are additional goals of this project. Three different crop rotations are being evaluated on an Iowa State University research farm. The first rotation (Rotation A) represents a corn-soybean system common to Iowa. The two other rotations represent alternatives to the common and include ‘third’ crops, double-cropping, and legume interseeding. In one alternative rotation (Rotation B), a corn crop will be succeeded by a double- crop of spring wheat and winter canola. In the other alternative rotation (Rotation C), corn will be succeeded by a double-crop of spring canola and winter wheat. The winter annual is planted shortly after the spring annual is harvested, thus providing ample time for the winter annual to establish and the best opportunity for winter survival. Red clover is then frost-seeded into the winter annual (canola or wheat) the following late winter/early spring. The red clover remains after harvest of the winter annual and over-winter into the following spring before being terminated for another corn crop completing the rotation. These latter two rotations ensure winter cover (in the form of a winter annual or perennial legume) in two of the three winters in each rotation. Moreover, these alternative rotations include three cash crops (corn, canola, and wheat) as well as a green manure legume crop (red clover) that may also increase farmer profitability by reducing farm input costs incurred by pest control and fertility requirements. The reduced reliance on these inputs may play a role in reducing the ecological footprint of farming practices. Furthermore, the increased winter cover can serve to reduce system leakages contributing to farm ecological footprint in the form of soil erosion and nutrient leaching.
The main objectives of this project are to:
1. increase the amount of information available to growers regarding canola as an alternative
oilseed or ‘third’ crop in Iowa;
2. increase the amount of information regarding winter canola, winter wheat, and red clover as
cover crops in Iowa;
3. assess the ecological and economical impact of the alternative cropping systems to be studied.
Ecological implications, such as entire-system fertility and mechanical input requirements among the rotations are being assessed. These implications will surely impact the financial competitiveness of the rotations. The diverse rotations generally require more passes through the field, yet costs of seed and fertility may in fact be greater in the conventional rotation making them more expensive. We continue to hypothesize that the reduction of synthetic fertilizer and weed control methods due to the inclusion of the alternative crops, compared to conventional cropping systems, will result in the economical competitiveness of rotations incorporating alternative crops.