Conventional farming uses way more fossil fuels than the average person might imagine. Of course there’s the diesel and gas fuels that are used driving farm implements, supplies, and products from here to there. But in addition to those, the main ingredients of fertilizers, herbicides, and pesticides are also fossil fuels. This is why, when oil prices rise, farmers see a triple whammy to their bottom lines.
So for every reason from economic to environmental, it makes sense for farmers to try and find ways to lower the amount of fossil fuels their farms use. But how can they do that without lowering output or increasing costs dramatically?
One way is to introduce new crop rotations that require less fertilizer and pesticide use. In the U.S. Corn Belt, most farmers get along by alternating between corn and soybean plantings over the course of two years. Although this is generally a profitable arrangement when oil prices are low, it requires large amounts of pesticides and fertilizers to keep it going because you are demanding much more out of the land than it can provide without external inputs. Because of that, this type of system is very sensitive to swings in oil prices.
Now, new results from a 6 year study indicate that by changing this type of crop rotation from a 2 year corn-soybean cycle into a three year corn-soybean-small grain/red clover cycle or a four year corn-soybean-small grain/alfalfa-alfalfa cycle, fertilizer and pesticide inputs can be dramatically reduced. In the 3 year cycle, fertilizer inputs decreased by 66% and herbicide inputs decreased by a whopping 80%. In the 4 year cycle fertilizer use decreased by 78% and herbicide use decreased by 85%.
The researchers from the study said that despite the lower inputs, the corn and soybean yields matched or bested the yields under a conventional 2 year rotation. The study ultimately found that the 3 year rotation can reduce fossil fuel use by 25%, and the 4 year by 56%, when compared to the 2 year rotation.
Of course, when you change from a 2 year rotation to a 3 or 4 year rotation, even though your yields for corn and soybean in a given year are the same or higher, you are producing less corn and soybeans overall due to the longer times between plantings of a given crop. The researchers indicate that, because of increases in labor costs associated with the 3 and 4 year rotations, many farmers are finding that even though they are hit with the triple whammy when oil prices increase, it still makes more financial sense to stick with the 2 year rotation.
If ethanol demand, oversees grain exports, or implementation of next generation ethanol from corn stover increase, the researchers conclude that farmers will have little incentive to switch away from systems that grow the most corn, but if oil prices rise without a corresponding increase in commodity prices, then these two lower input systems might become more popular.
As the researchers say, it’s very hard to predict what kinds of market demands the future holds, but at least now we know that farmers have options to maintain high yields profitably in the face of rising oil prices.
Image Credit: James Jordan/flickr