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Soil Health during Drought
by Jacob Hawes, Soil Conservationist
In the last several weeks, many farmers have expressed a concern over the lack of precipitation received this spring and the looming potential for a drought heading into summer. Although drought is experienced by all farmers, those who no-till will have a big advantage. At the surface level residue from the previous year provides a layer of protection that prevents evaporation by shielding the ground from the sun and wind. There is much more going on below the surface in no-tilled fields where the soils are able to better tolerate dry conditions and maintain moisture.
Within the soil is an entire ecosystem made up of earthworms, arthropods, plants, bacteria, fungi and more, working together to recycle nutrients and improve soil health. One essential element is a glycoprotein called glomalin, that is a critical component to improving soil health. This protein is produced on hyphae, or root like structures, of mycorrhizal fungi that colonize plant roots. When glomalin is produced, it increases the rigidity of the hyphae allowing it to extend further from its host plant and improves the ability to scavenge and transport water, minerals, and nutrients back to the plant. Fungal hyphae only last for several weeks, but as they breakdown the glomalin that was produced can remain intact for decades and acts as a glue that holds soil particles and organic matter within the soil together to form aggregates. These aggregates help improve the stability of soil and help prevent leaching of nutrients while increasing carbon storage in the soil. Glomalin could be responsible for up to one-third of the carbon storage within the soil. As aggregates form and soils stabilize macropores, or channels made by other soil life, remain intact and increase the soils’ ability to act as a sponge by improving water infiltration and the water holding capacity.
The production of glomalin isn’t a fast process and can take several years of no-till for soils to reach their potential. Adding cover crops into your rotation can accelerate glomalin production by keeping the soil biology alive throughout the year and reducing the time it takes for mycorrhizal fungi to colonize and begin producing glomalin each season. Additionally, avoid over-applying synthetic fertilizers and unnecessarily applying fungicides that can restrict or even kill the beneficial fungi and other organisms in the soil. Lastly, avoid tillage at all cost. Each time tillage occurs, the mycorrhizal network in the soil is fragmented and the glomalin holding soil aggregates together is broken down. With each tillage pass aggregates get finer and finer, eliminating the pores in the soil, essentially sealing the soils surface and severely reducing water infiltration into the soil.
If a drought is just around the corner, take note of the fields that you see this spring that are no-tilled and be sure to check back during the driest part of the summer. While surrounding fields may be wilting and yellow, the no-till fields will often still be vibrant and green. For some farmers on the fence about no-till, this may be just the push they need to make the switch or change up their management system.
