2019-01-09 / Local News

Consider this for a resolution: Give your soils a check-up this year

By Don Donovan
District Conservationist, NRCS

Those of us in agriculture have seen and will continue to see and hear the term “soil health” pop up more and more in the months ahead. First of all, what is meant by soil health? In general, soil health can be regarded as overall soil quality, or you might say that it refers to the environment a soil provides for plant growth.

I want to draw attention to the aspect of soil health that deals with the balance and quantity of beneficial microbial life in the soil. Soil with a healthy population of both bacteria and fungi will provide many agricultural benefits resulting from improved aggregation, nutrient cycling, and organic matter production.

I am guessing most land users have not thought much about soil life. You may be aware of the good things that visible organisms such as earthworms do for the soil. However, we should also be concerned with the part that microscopic organisms play in soil function. It has a lot to do with the battle between bacteria and fungi for the resources within the root zone of our crop plants.

An important aspect of soil biology is that certain types of fungi are critical in aggregating soil, which improves natural drainage and at the same time, water-holding capacity, among other benefits, as well as enhancing the ability of plant roots to take up nutrients. So, the biological condition of the soil has a big impact on other characteristics that we are used to seeing, such as drainage, tilth, residue decomposition, and plant condition.

You may be wondering how to evaluate soil health. Most of us do not have a microbiology lab in the shop…soil microbial analysis is actually a possibility, but these tests are not yet widely available. There are simpler ways to evaluate soil health through some simple observations of soil condition. A shovel full of soil, especially when compared to that of other fields with different soil types or management, can tell us a lot about soil structure (aggregation), drainage, and whether there are concerns such as compaction. Earthworms are always a good sign.

A soil test report is another good tool to use. If your organic matter (OM) content is decreasing over time, it is likely your soil health is declining with it; or, if you note an OM percent increase over several sampling cycles, that is definitely a good indication. In my opinion, building soil OM should be a high priority in a soil health management system.

A healthy soil is a more productive soil – now how do we manage for it? It boils down to two basic principles: Disturb the soil as little as possible and keep something growing in the field as much of the time as possible. The impact of tillage is not easily seen over a short period of time, but over years and decades, the effect is destructive to soil health. Tillage does in fact destroy soil organic matter, in addition to the potential for erosion, tillage results in the breakup of soil aggregates which house beneficial fungi and allow soil bacteria to go on a feeding frenzy with newly exposed sugars and other “glues” that bind soil aggregates. In short, soil bacteria literally eat a small portion of soil OM after tillage, all the while multiplying and disrupting microbial balance, which makes it more difficult for the soil to re-establish structure.

As for the second principle, any crop farmer serious about improving soil function should consider cover crops. The fungi that benefit our crops need living plant roots to thrive. Cover crops offer many agronomic benefits, and important among them is the maintenance of mycorrhizal fungi that live in association with plant roots and increase nutrient uptake. Your cover crop will also generate organic matter, reduce erosion, and do work for you that no piece of equipment can match.

If interested in the health of your soil, contact District Conservationist Celia Tharp at the local Natural Resource Conservation Service or NRCS office at (765) 564-4480 ext. 3. Together, you can visit the farm and discuss strategies to improve soil function. There are financial assistance programs available to help with changes to your system.

Return to top