Healthy soils are critical to successful farming operations. They increase the ability of crops to withstand weather variability — including short-term extreme weather events during the growing season — as well as the capacity to store water, sustain a healthy microbial community, and maintain good nutrient cycling potential. And these benefits are most evident when growing conditions are less than ideal.
Soil health is defined by the level at which it will continually sustain plants, animals, and human lives. The properties of soil influence plant water availability, off-field nutrient losses during rain events, and the availability of nutrients for fuel, food, and fiber production. Put simply, healthy soils are critical to sustaining bountiful agricultural production and supporting wildlife habitats.
What affects soil health?
Soil organic matter is a central property that influences its health, and it is heavily affected by management practices like tillage. This — in addition to crop rotation, crop diversity, and weather conditions — impacts the soil’s physical, biological, and chemical functions. A well-managed soil can increase the storage and supply of nutrients to plants, microbial diversity, and carbon storage.
Intensive tillage and mono-cropping systems can cause soil degradation, weakening soil structure, and reduction in the microbial community that is essential for healthy crops. Soil degradation is always associated with intensive tillage, especially during the spring season. This is when soils are most vulnerable to water erosion in areas with high rainfall or wind, as there is a lack of crop residue cover to protect the soil surface.
Sustaining crop production
The benefits of increasing organic matter with conservation practices such as no-till (NT) can be translated into yield savings, especially in times of drought. A long-term study conducted in Iowa found that there is a 50-70% increase in water recharge in the soil profile with NT as compared to conventional tillage. This increase in water storage can have significant effects on yield.
In the 2012 drought, corn yield reduction in some parts of the state exceeded 40% with conventional tillage compared to 15% with NT. This is due to the benefits of NT in improving the biological, chemical, and physical properties of soil, largely because of the crop residue left on the soil surface. Residue can minimize erosion and protect original soil organic matter from decomposition.
To the average person, it may just look like “dirt,” but soil is essential for the farms that feed and fuel the world. Healthy crops and hearty yields start from the ground up.