Soil is like an engine, helping to drive higher yields and profits. And the investments in making that engine run—seed, fertility, crop protection—aren’t small. It pays to keep that engine operating at peak performance—to occasionally look under the hood—and evaluate the overall health of the soils you farm.
Well-managed soils are healthier and produce better crops. Here are key measures of soil health and tips for improving soil health.
Measure #1: Pore space
Most soils are about half solids and half pore space, with the pore space being either air or water. And that pore space is where the action is.
When you create soil compaction, usually with tillage or wheel traffic, you’re removing the larger pores in the soil. Compacted soil interferes with water infiltration, root penetration and the amount of available water and biological activity.
Deep ripping isn’t always the answer because it doesn’t actually eliminate compaction. It just moves the compacted band deeper into the soil profile.
Measure #2: Organic Matter
Organic matter (OM) binds the soil together and improves soil structure by increasing pore space and the soil’s water-holding capacity. It also improves biological activity and increases the cation exchange capacity, which allows for the movement of nutrients from the soil to the plants.
While you can lose OM to erosion or by speeding up decomposition with tillage, other techniques—such as no-till or cover crops— can help to increase OM. In fact, soil OM can increase by up to 10 percent with a commitment to proper management, according to the Natural Resources Conservation Service (NRCS).
Measure #3: Microrganisms
There’s a whole host of organisms that live beneath the soil surface. We’re all familiar with earthworms and nematodes, but there are others busily involved every day in recycling nutrients. The diversity and balance of all of these critters living together can be heavily impacted by how you manage your soils.
According to the NRCS, there are four main areas to consider when promoting soil health:
Tip #1: Reduce soil disturbance
- Tillage results in bare and/or compacted soil that is destructive and disruptive to soil microbes
- Misapplication of farm inputs can disrupt the symbiotic relationships between fungi, other microorganisms, and plant roots.
- Overgrazing reduces root mass, increases runoff and increases soil temperature.
Tip #2: Increase plant diversity
Because a diversity of plant species supports the diversity of soil microorganisms, the key to improving soil health is ensuring several types of plants or animals are present in a cropping system. This fully functioning “soil food web” allows a soil to express its full potential.
- Growing different plants in rotation increases plant diversity.
- Using cover crops aids soil health and soil function, reduces input costs and increases profitability.
Tip #3: Keep living roots growing
The rhizosphere is an area of increased microbial activity, close to the root, where roots exude microbial food to attract and feed microbes that provide nutrients (and other compounds) to the plant.
- Grow long-season crops or a cover crop following a short-season crop to feed microbes as much as possible during the growing season.
- Healthy soil needs well-fed microbes. Providing plenty of easily accessible food to soil microbes helps them cycle nutrients that plants need to grow.
- Sugars from living plant roots, recently dead plant roots, crop residues and soil organic matter all feed the many and varied microbes present in the soil.
Tip #4: Cover the soil surface
- Soil cover conserves moisture, reduces temperature, intercepts raindrops (to reduce their destructive impact), suppresses weed growth, and provides habitat for members of the soil food web that spend at least some of their time above ground.
- Keeping the soil covered while allowing crop residues to decompose (so their nutrients can be cycled back into the soil) can be a bit of a balancing act.
- Consider how your crop rotation (including any cover crops) and residue management decisions can keep the soil covered and fed at the same time.