The foundation to a successful crop production system depends on good soil. Sound soil management is required to meet essential plant needs for water, nutrients, oxygen, and a medium to hold their roots with as little management as possible.
Terms like “soil health” and “soil quality” have become popular terms when discussing soils.
In many cases, the term soil health is used interchangeably with soil quality. In general, soil health, as a measure of soil functions, can be defined as the optimum status of the soil’s biological, physical and chemical functions.
In simpler words, this means healthy soils can sustain plant and animal productivity, soil biodiversity, maintain or enhance water and air quality, and support human health and wildlife habitat.
The definition of soil health provided by USDA-NRCS states, “soil health is the continued capacity to function as a vital living ecosystem that sustains plants, animals and humans.”
A healthy soil is not just a medium to grow plants, but rather a living, dynamic and changing environment that is influenced by what we do and the practices we adopt as human actions. Soil is a dynamic and living organism.
Soil health suggests that soil is an ecosystem that needs to be carefully managed to function optimally. Important soil functions would include:
• Retaining and cycling nutrients
• Supporting plant growth
• Allowing infiltration, promote storage and filtration of water
• Supporting the production of food, feed, fiber, and fuel
• Suppressing disease, insects, and weeds
• Sequestering carbon
• Detoxifying harmful chemicals
When soil does not perform to its potential, the long-term result can jeopardize productivity and environmental quality, thus affecting production and profit. If we know what constitutes a healthy soil we can then better manage our soils.
So, let’s look at the different characteristics that make a healthy soil:
Soil tilth refers to the overall physical characteristics of the soil and its suitability for crop production. Soil with good tilth is crumbly, well structured, dark with organic matter, and has no large and hard clods.
To me good tilth goes hand-in-hand with good soil structure. Soil structure refers to the way soil aggregates, particles, and pore spaces are arranged. Soil management practices, like plowing, cultivating, applying lime, adding organic matter, and stimulating biological activity, can influence structure.
Lack of structure can affect plant growth in many ways. Poor structure affects air exchange and water movement, which in turn affects nutrient utilization. Lack of structure influences the quantity and size of pores which can directly impact root growth and development.
Sufficient depth refers to the extent of the soil profile through which roots can grow to find water and nutrients. A soil with a shallow depth as a result of a compaction layer or past erosion can be more susceptible to damage in extreme weather, thus putting a crop at more risk to flooding, pathogen attack, or drought stress.
A healthy soil will retain more water for plant uptake during dry times but will also allow air to rapidly move back in after rainfall, so that organisms can continue to thrive.
An adequate and accessible supply of nutrients is necessary for optimal plant growth and for maintaining balanced cycling of nutrients within the system. An excess of nutrients can lead to potential water quality issues, high nutrient runoff, as well as toxicity to plants and microbial communities within the soil profile.
Plant pathogens and pests can cause diseases and damage to the crop. In a healthy soil, the population of these organisms is low or is less active. Healthy plants are better able to defend against a variety of pests.
Soil organisms help with cycling nutrients, decomposing organic matter, maintaining soil structure, biologically suppressing plant pests, etc. A healthy soil will have a large and diverse population of beneficial organisms to carry out these functions and thus help maintain a healthy soil status.
A healthy, well aggregated soil is resilient, full of diverse organisms and is more resistant to degradation from wind and rain erosion, excess rainfall, extreme drought, vehicle compaction, disease outbreak, and other potentially damaging influences.
It is important to recognize soil constraints that limit crop productivity, farm sustainability, and environmental quality. Management practices can be adjusted to alleviate these problems. The following is some of the more common soil constraints commonly observed in unhealthy soils:
Soil compaction can occur at the surface and subsurface soil profile. Be sure that the soil is ready for equipment prior to tilling.
Poorly aggregated soils are more susceptible to erosion and runoff which increases risk of lost productivity. Aggregates are formed whenever mineral and organic particles clump together.
Weed Pressure, when plants are unhealthy and “weak” they are less able to compete against weeds for water and nutrients and defend themselves against pests.
High pathogen pressure, root pathogenesis negatively impacts plant growth and root effectiveness as well as minimizes contributions from microbiota in proper functioning of important soil processes.
Low water and nutrient retention, lower organic matter in soils indicate poor structure and lower water holding capacity. Therefore nutrient mobility and plant growth will be limited.
As you work your soils, good sound soil management can begin, and the dividends of better crop production can hopefully be seen.
Further needs would be to conduct a soil test which your local County Extension Office can assist you with, if needed.
Knowing and understanding the health of your soil along with knowing your soil fertility will certainly help in implementing proper soil management techniques.
Tony Nye is the state coordinator for the Ohio State University Extension Small Farm Program and has been an OSU Extension Educator for agriculture and natural resources for over 30 years, currently serving Clinton County and the Miami Valley EERA.