Three or four year crop rotation vs corn/soybean rotation
In many circles, it is taken as a matter of fact that to be able to feed an additional 2 billion people by 2050, farmers everywhere are going to have to adopt the intensive agricultural practices that have been perfected in the US heartland where massive amounts of corn and soybeans are harvested almost every year. For the most part, this production system also separates crop agriculture from livestock agriculture composed of large chicken complexes, huge hog production facilities, and massive feedlots.
The implication of all of this is that only with this type of system will agriculture be able to meet the food demands of a rapidly growing population. Sustaining this model of agricultural production involves the heavy use of herbicides, insecticides, and synthetic fertilizers, all of which have significant environmental impacts. The system is also heavily dependent upon the use of fossil-based energy to produce the synthetic fertilizers that are crucial to the system and the fuel that is needed to cultivate fields, plant the crops, harvest them, and transport the corn and beans to feed mills that prepare the rations used in the various meat production systems.
Iowa State University with funding from the United States Department of Agriculture (USDA), the Leopold Center for Sustainable Agriculture, the Iowa Soybean Association, and the Organic Center conducted a field study from 2003-2011 that compared the typical 2-year corn/soybean rotation, with 3-year and 4-year rotations that included both crops and livestock.
The results of their study was published in a PLOS-One paper titled, “Increasing cropping system diversity balances productivity, profitability, and environmental health” . The researchers “hypothesized that cropping system diversification would promote ecosystem services that would supplement, and eventually displace synthetic external inputs used to maintain crop productivity.”
The authors write “One of the key challenges of the 21st century is developing ways of producing sufficient amounts of food while protecting both environmental quality and the economic well-being of rural communities. Over the last half century, conventional approaches to crop production have relied heavily on manufactured fertilizers and pesticides to increase yields, but they have also degraded water quality and posed threats to human health and wildlife. Consequently, attention is now being directed toward the development of crop production systems with improved resource use efficiencies and more benign effects on the environment.”