Submitted to: Trade Journal Publication
Publication Type: Trade Journal
Publication Acceptance Date: 11/10/2014
Publication Date: 12/1/2014
Citation: Osborne, S.L., Lehman, R.M. 2014. Feed your soil through diversity. South Dakota Corn Magazine Emerge, p. 21.
Technical Abstract: Our soil resource is fundamental to plant and animal life, therefore, proper management is essential. One of the key tools to maintain our soil resource is diversity both below and above ground. Diversity is an important concept in all areas of our lives, from the food we eat, to the weather we experience in South Dakota. Our soils are a living organism that must have a diversity of food to thrive, just like our own bodies. We cannot eat just one specific type of food, we must have diversity to get the vitamins and minerals our bodies need to thrive. The soil and the organisms that live within the soil are no different. So this leads to the question; how do we give our soils and soil microorganisms the diversity they need to thrive? One possible solution would be to have a diverse mixture of crops growing in the soil all year long. But within our current production system this is not always an economical option. Other factors, such as producing feedstocks for biofuel production; as well as traditional food, feed and fiber crops, may also drive cropping diversity. Cover crops are an option that producers can utilize to add diversity to their current production system without replacing their traditional cash crop. Cover crops can be defined as any annual, biennial, or perennial plant grown alone or in combination with the cash crop. One way a producer could introduce diversity into their production systems would be growing a combination of cover crop species in a mixture. Another important aspect is to ensure that these cover crops and their roots are present when our traditional crops are not, late fall after harvest and early spring prior to planting. Just like us the soil needs to be feed year around not just in the spring and summer. Having diversity in the crops grown along with the presence of these crops and roots in times when the soil is otherwise bare can have a substantial impact on improving our soil resource and thus soil health. Cover crops have been shown to increase our soils’ ability to withstand the forces of both wind and water erosion, and increase its ability to capture and store water. The presence of crop crops can have a positive impact on the belowground biological diversity. A healthy and diverse soil microbial population increases the range of mechanisms that promote biological carbon and nutrient cycling, providing nutrients to the crops at the times of highest demand. Increasing soil microbial diversity is also important to support specific groups of microorganisms which have specific functions, such as arbuscular mycorrhizal fungi (AMF). These fungi live in association with plant roots and increase the supply of immobile nutrients (phosphorus, copper and zinc) to plants. An added benefit of the presence of AMF is increasing the volume of soil from which plant roots can take up essential nutrients and water. When AMF are present, plant roots can explore approximately 1000 times more soil volume than when there are no AMF present. This provides additional advantages to the plant in terms of drought resistance, pest resistance, and improving soil structure. A plant host is required for AMF to grow and reproduce, and cover crops provide a green bridge between annual crops for these important soil organisms. Good soil health can protect yields under stressful conditions, and cover cropping is a great way to promote soil health by maintaining a growing plant on fields for as much of the year as possible. Growing plants pump carbon and nutrients into the ground, feeding soil organisms, and do the same as they senesce by virtue of their residues. Above-ground, cover crops have visible effects on soil aggregation and resistance to erosion – try it and make your own observations!