Climate change and agriculture

Recently there has been much political discussion on the effects of global climate change and how new regulation will affect farmers in Minnesota and around the nation. Our Intern Kimberly Maas looked into some recent research from the Agriculture Research Service (ARS) concerning this topic. As expected the answers are not as simple and clear cut as we would like. The interactions of climate and agriculture are an incredibly complex system and we are just beginning to grasp the connections between common agricultural land use practices and climate. Luckily for us, the scientists at the ARS are contributing some objective scientific information to what has become a very heated political debate. Here is what Kimberly found:

Scientists of the Agricultural Research Service have been looking at alternative tillage methods and fertilizer use that help keep reduce the amount of greenhouse gases released into the atmosphere. Scientists have compared conventional methods of plant growth and harvest with alternatives. For over five years, ARS has conducted research in 32 research locations across the country. These locations compare and communicate with one another to work toward creating a national database of how greenhouse gases fluctuate and how carbon is stored. The benefit of multiple research stations is that emissions of greenhouse gases vary from region to region dependent upon such variables as the amount of rainfall, quality of soil, and temperature.

In a six-year study conducted by ARS, no-till corn was planted into the remnants of brome grass sod. The researchers discovered that the switch from grass to corn did not contribute to a change in the amount of greenhouse gases that were emitted. Researchers found that during the switch from grass to corn, yields may decrease due to outside weather conditions. However, the amount of carbon from brome grass that was lost during the switch was replaced by an increase in the amount of carbon put into the soil from corn.

Such practices as chisel and moldboard plowing are known to increase emissions over a short period of time. However, by one year, the emissions from plots with intensive amounts of tillage and those without were the same. Researcher Ronald Follett and his team discovered during 6 years of work, that by using a no-till system, the pattern of organic carbon in the soil held even through both good years and bad dry years. During years when the soil is dry and parched, the release of carbon into the atmosphere should be worse than years when there is no drought.

Reducing emissions is more complicated than cutting back on the amount of nitrous fertilizer that is applied or in changing crop rotation cycles. Crop rotation systems do not have an overall impact on the amount of green house gasses emitted back into the atmosphere. However, rotation methods may still have an overall impact on other conditions such as the economy and soil erosion. When it comes to reducing the emission of green house gases, what is really important to consider is tillage. The type of tillage such as no till, or strip till can have an effect on the amount of gas emissions released back into the atmosphere.