Is runoff the true soil issue in Ohio?

Whether you live in the state of Ohio or not, you have probably heard of the harmful algal bloom (HAB) on Lake Erie, or the Dead Zone (Hypoxic conditions) in the Gulf of Mexico.

Both issues are wreaking havoc amongst many different demographics of the population. Recreational boaters, commercial fisherman, conservationists, lawmakers and many others have been thrown into a nightmarish situation trying to solve the issues that are causing the degradation of our water resources.

Contamination?

The blame often is placed on the contaminated runoff flowing from our agricultural operations and farm fields. As it rains, runoff flows across the fields, picking up small soil particles which have nutrients such as Nitrogen (N) and Phosphorus (P) attached to them.

These soil particles, along with the nutrients, eventually end up in our water systems. Lakes, rivers and bays are being polluted with excess soil runoff and an overabundance of nutrients.

Experts commonly look at ways to filter this runoff with wetlands, filter strips and riparian buffers, all of which are great management practices. But what if we look at the problem not as a runoff issue but an infiltration issue.

Rainwater or snow melt is absorbed into the soil, filling the small open pore spaces between soil particles. When the structure of the soil is degraded, usually through tillage or disturbance, those open spaces are not as plentiful.

Commonly a layer of compaction is formed that limits water infiltration into the soil. Generally, plants need a few things to grow — soil, water and sunlight. Most years we have periods of large amounts of rain and periods of drought.

Healthy soil

Why are we not looking at how we can increase the health of our soil, thus increasing the infiltration rate of that soil as well as its holding capacity? By doing so, we will be able to increase the infiltration of water and have it flow through our soil layers regenerating our ground water as well as increasing water availability for our crops.

How many farmers or landowners know what the infiltration rate of their fields or gardens are? We are seeing many more strong downpours in recent years. If we get two inches of rain in an hour, how much is making its way into your soil? We seem to always wonder and ask how much rain was in the rain gauge, but that information tells us very little for our crops.

What we need to know is how much rain has infiltrated into our soil. If your infiltration rate is only 0.5 inch per hour and we receive 3 inches of rain in an hour, it’s not doing your crop much good.

Soil organic matter

So how do you increase your infiltration rate? That begins with building soil organic matter (SOM). Before settlement in this area of Ohio, it is believed the SOM was around 6%. Now on crop ground, the average is probably around 1.5 to 2%. Tillage and conventional farming practices have reduced the levels of SOM down to barely anything.

An important thing to note about SOM is that for every 1% increase in SOM that soil can hold 17,000 to 25,000 more gallons of water per acre. What we need to look at is how to build that soil organic matter to increase the amount of water our soil can hold and make it available to our plants.

To increase SOM, we must limit disturbance, keep the soil armored with plant life year around, add diversity through animals and plants, keep a living root in that soil year around, and integrate livestock grazing into our operation more. By working with these principles through a variety of implementations, we can solve a lot of resource issues.

Inventive ideas

Farmers are coming out with inventive ways to accomplish these points each year. Diverse mixes of cover crops planted into the cash crops with high-boy seeders or aerial application are great ways to see lots of biomass growth even before harvest. Some people are seeding corn on 60″ rows and planting covers between them to add diversity to their fields and make up for a yield loss by grazing livestock.

It amazes me the ingenuity of farmers when they try to tackle these issues. In doing so, they often come up with easier management strategies and healthier, more nutrient-dense food. Soil that acts like a sponge can sustain growth much easier than depleted/over-tilled soil.

As the soil heals and more pore space is opened, roots can grow further down and access more water and nutrients — in turn offering the potential for a good yield with lesser inputs.

If you would like to learn more about practices to increase soil health and infiltration, feel free to contact your local soil and water or NRCS office.