Soil Microbes are Key Partners for Drought Management By DR. KARL WYANT | Vice President of Ag Science, Heliae® Agriculture; Chair, Western Region CCA Board of Directors
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anagement practices that improve soil health and soil quality have gained considerable attention over the past few years, and especially during the past year, as drought conditions have impacted large areas of North America. In this article, I focus on how the living, biological components of the soil (e.g., bacteria and fungi) can be key microbial partners in your future drought management strategy.
Soil Health and Drought Management
Figure 1. Here are two concepts to help organize the contribution of microbes to soil health and structure (Concept 1) and the substances that are released by the microbes themselves (Concept 2) that help crops get through a drought period (courtesy K. Wyant.)
I detail how soil microbes impact soil physical properties, including the structure (e.g., aggregation and pore space) and the ability of the soil to move and store water. Additionally, I explain how soil microbes can help crops get through drought conditions using the substances they secrete. Finally, I close with a call to action to measure your soil biology so you can make management decisions now before the next season gets underway. If needed, a CCA can help you interpret data and make an actionable plan that can help tackle the continued drought conditions that are expected for the near future. Let us begin with a quick reminder of what soil health means to a grower and how it is connected to the living component underground and drought management. Soil health is directly related to the interaction, or lack thereof, between organisms and their environment in a soil ecosystem 18
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and the properties provided by such interactions. When you think of soil health, think of the biological integrity of your field (e.g., microbial population and diversity) and how the soil biology supports plant growth. There is a direct link between soil health and how a soil can be managed to meet the challenges of drought conditions.
as water infiltration. If you are not capturing and moving water into the soil, you will have a tough time storing water in your field. Simply put, healthy soils have good structure, which excel at receiving and storing moisture. But how exactly do microbes improve water penetration and infiltration?
Concept 1: Soil Microbes Help Increase Water Penetration and Infiltration
Abundant and diverse soil microbial communities produce “free” services for your farm soil, including the ability to receive and store moisture. The key to this ability lies in the ability of microbes to contribute directly to improving soil structure by binding soil particles together, which, in turn, helps water move from the soil surface and into the root zone.
Soil microbes help restore soil structure which helps water move from the soil surface downwards. This is known as water penetration. Once the water has penetrated the soil, it moves down into the soil for storage. This is known
Soil bacteria produce a sticky, gluelike gel called extracellular polymeric substances (EPS) that form a protective slime layer around bacteria as they grow. The EPS acts as an adhesive to bind soil particles, thereby improving
Soil Microbes and Drought Management
Soil microbes impact your ability to manage drought via two major pathways, i.e., the “Two Concepts of Drought Management” (Figure 1).
January / February 2022