When we look at our soil health and take into consideration the cold, wet soils of this spring and the later planting dates, we know we may have been in some fields where we shouldn’t have been. Whether you were in a conventional tillage or no-till situation, conditions were less than ideal. If your soil was in good shape to start this spring, you probably had the opportunity to come through those conditions in a much better position than those who were dealing with poor soil health.
Improving Soil Health
We first need to evaluate what is going on with our soil before making any adjustments or improvements. Ideally, we are looking for soil with a good “crumb” structure. Using a penetrometer, or even a shovel and doing some digging, can tell you a lot about your soil.
A plant root can only penetrate soil with 300 lb./sq/in of pressure. If a penetrometer reading is higher than this, you will want to look at options such as fall tillage, although this does not help an already growing crop. I hesitate in bringing up a cultivator, as this practice doesn’t work in a no-till situation, and there is less frequency of cultivating in many areas. Sometimes, simply getting air into compacted soil can create a big response for plant growth.
Cover Crops
If you are in a no-till situation, consider the use of cover crops. For compacted soils, radish, turnips, and rye can do a lot of good. The root systems of cover crops penetrate deeply and bring nutrients back to the top of the soil to be broken down, and essentially recycled for the next generation of plants. Depending on your soil type and what you wish to accomplish, there are a number of different cover crop mixes that may be more beneficial than the use of a single cover crop species.
Soil Biology
Soil is made up of 25 percent air, 25 percent water, and 50 percent mineral and organic matter. Biological activities are taking place in this environment to break down the plant residues which are present. This happens in the aerobic zone. With the presence of oxygen, the bacteria and fungi can thrive, given available food sources. The deeper our aerobic zone, the more live soil we are farming.
In a row crop rotation, I look for a 1/1 ratio of bacteria to fungi. Bacteria will break down simple carbon compounds, such as root exudates, to make it readily available to plant roots. Fungi primarily decompose the lignin and hard-to-digest soil organic matter. They also physically bind soil particles together, creating stable aggregates that increase the “crumb” structure of the soil. This allows more water to infiltrate, but with less chance of erosion. Mycorrhiza fungi will attach to growing plant roots and act like a giant spider web in the soil. The plant roots will feed simple sugars to the mycorrhiza in exchange for minerals etched from the soil and provided by the fungi.
Looking at your plant’s root system and your overall soil structure can give you a good idea of what is taking place in your soil. This, coupled with accurate soil and leaf tissue samples, should give you a better idea of your fertility levels and how to improve crop yields. For more information on soil health and improving yields, contact your local Beck’s agronomist.
~ Jerry Mathis, CCA – Field Agronomist