It’s a good idea to pay a visit to your doctor every year — even if you’re feeling fine. A complete physical exam can give you the peace of mind to keep doing what you’re doing, or it could uncover areas of concern.
Soil is no different. “By evaluating the health of soil, we can get an idea of what’s good; what’s bad; learn where to start making improvements; and set benchmarks to measure progress,” explains Farm Journal Field Agronomist Ken Ferrie. “The process can tell you if a piece of land you’re thinking about renting or purchasing is a sound investment.”
What to Assess
There’s no time like the present to add a soil physical exam to your arsenal of management tools. Start by evaluating these three aspects of soil — its chemical, physical and biological properties.
- The chemical component can be monitored with a soil test. Fixes are relatively easy, Ferrie says. Apply fertilizer to achieve balance and maintain it to stay balanced.
- The biological components of soil can be detected through in-field and lab testing. Test in the spring when soil moisture is close to field capacity, Ferrie suggests.
- The physical component is a little more complicated because there are a variety of potential causes and corresponding solutions. Physical aspects include soil texture, aggregate stability, available water capacity, surface and subsurface hardness and infiltration rate. Tools such as slake tests and soil probes and penetrometers help you accurately diagnose problem areas.
Set Soil Goals
Chemical properties can be improved in a relatively short time with management techniques, says Joseph Amsili, Cornell University Extension associate and New York Soil Health Initiative program coordinator. However, soil organic matter, which is a keystone soil health indicator, is one of the slowest to change.
“By understanding these properties, you can brainstorm short-term and long-term goals,” he says.
For example, say you determine a field has a subsurface compaction issue. A short-term management plan might include some deep ripping and cover crops (radish or sorghum sudangrass) that are well adapted to breaking up compaction.
A long-term strategy, Amsili says, could include avoiding heavy loads and traffic when the subsoil is wet.
Expand Your Herd
Ultimately, soil health boils down to the health of soil organisms, Ferrie says. Simply put, healthy soil contains more life.
“It’s no exaggeration to say the ‘livestock’ in your soil are as important as the livestock in your feedlot or dairy, and just as sensitive to their environment,” Ferrie says.
You want those soil-dwelling creatures to be plentiful and active, decomposing residue and recycling its nutrients into forms your crops can use. You can actually see a few of those valuable creatures, such as earthworms and night crawlers, but most are invisible to the naked eye and live beneath the soil’s surface.
Working together, soil organisms create what you might call the cycle of life. “The first wave is macro-organisms such as night crawlers, which introduce residue to the soil,” Ferrie says. “Then fungi, bacteria and actinomycetes join in. As they break down carbon chains for their food source, they release nutrients, such as nitrogen, phosphorus and sulfur, which are held in the carbon chains.”
The soil organisms mineralize these nutrients into inorganic, or soluble, forms that can be taken up by plants and microbes.
Increasing your microbial populations involves the same practices you’ve been using to grow higher yielding crops, Ferrie says. Improve oxygen and water infiltration (shoot for the ideal 60/40 oxygen to water ratio in the soil) by removing dense and compacted layers.
Try to incorporate cover crops or other cash crops into your rotation.
“Various species of microbes prefer different residues,” Ferrie points out. “Diversifying the microbe populations makes your soil more resilient to stress.”
Similar to every aspect of management, soil health requires a long-term strategy.
“Soil health is somewhat like human health,” Ferrie says. “The immediate consequences of being overweight and out of shape may not be a big deal when you’re young, but they can shorten your life, or reduce the quality of your life, many years later.”
Soil Sample With Purpose
Typically, soil health sampling falls into one of two broad categories, says Cornell University Extension’s Joseph Amsili. They include:
General field sampling is ideal for establishing a baseline before applying treatments or for areas where you want to assess general needs. Once baseline conditions of the farm are understood, the information can be used to further define problems and opportunities.
Troubleshoot sampling is more targeted and is ideal for comparing areas with uneven crop performance or different field management units (Area ‘A’ versus ‘B’). With targeted sampling you are trying to answer a particular question.
Download the Soil Health Stewardship guide for instructions on how to evaluate your fields.
