Lawncology® 38: Saturated Soils

When it rains it pours! That saying couldn’t be more true with the sudden shift from mild temps to winter rains and cold daytime highs gripping the eastern United States. While having this water is welcome after last year’s drought in the south east, it can become overbearing and intolerable for our own minds and wellbeing as well as for our soil. There is only so much saturation that any soil can handle and depending on your soil type, this will vary greatly.

Soil types such as clay, sand or loam all have a different water holding capacity and further, as organic matter increases across any soil system, both the plant available water and the soil holding capacity go up in kind. This is great under normal precipitation, but what happens when soil becomes over saturated, does this change the soil or the relationship to the plant? This has become a question that I have gotten multiple times in areas that were hard hit by hurricanes and floods and the answer is yes, there is an impact on structure of the soil and the life that abides within.

Water is life giving. Without it, nothing on this planet would exist. Too much of it and the same result can happen… Plants can drown just as any human or animal can, at some point there becomes too much water that displaces air and the result is hypoxia. Lack of oxygen in the soil will nearly eliminate soil life and if the soil itself isn’t washed away, create a bed of decaying soil life for new life to birth into as the water recedes. So… there‘s that.

Secondly, if we aren’t talking about water totally covering turf (like in a flood) and just hypersaturation of the soil, we run into the same problem but different. The soil life will still suffer but then, so will the roots of the turf. Root rot is fairly common and if this doesn’t fully happen, shallow roots most definitely can. There will be a shed of roots into the soil profile (which will build OM and ultimately help) but in the meantime, the roots will be looking for air as well. This can lead to stress later on if water management isn’t handled correctly after the heavy rains end.

When the highly saturated soils continue for an extended period of time and the roots begin to thin, the next domino to fall is the density of the turf itself. As root systems fail and the ability for nutrients to be moved upward into the leaf tissue is lessened, the overall vigor of the turf will decrease greatly. This leads to the next domino… weeds. Maybe you were expecting me to say fungus, but that comes later. Weeds will propagate quickly in these newly found open spots in the soil and their roots will go to work in the areas where the turf has lost the most of its foundation. Natures soil builders (weeds) are going to grow rapidly to fix the problems from all that water.

Another thing that happens under intense water saturation is the loss of overall nutrients in the soil. Most of your soluble or more mobile nutrients are going to move with the water, salts have a tendency to rise up from deeper soil layers and cause issues in the root zone as well. All of this needs to be considered when you go out to start feeding your lawn or lawns that have been soaked for too long. An overall adjustment to the nutrient load for the rest of the year will likely need to take place.

I suppose I could mention fungus now. Depending on how much attention is paid to soil building after these rain events, the probability of higher fungal outbreaks in the summer goes up tremendously. Anaerobic soil and decreased digestion of dead matter will provide a wonderful summer home for a fungi. Sounds like a lot of fun, right?

Here’s the way that I’ve always handled these scenarios and honestly, a proactive approach will be your best friend. Potassium. This is going to be vital if prolonged saturation is present. This electrolyte can help to keep roots from over saturating and actually preserve them longer in these situations. Watch your pre-emergent. This is going to be a hard one based on the severity of the thinning of the turf and roots, loading up a pre-m can slow the recovery of your turf, but it’s a fine line to walk due to the possibility of high weed infestation. Depending on your turf type, you may have the ability to increase turf density in the summer months and be free and clear to get that chemical down early. Humic. You have to rebuild what was lost and encourage new growth of soil life. And lastly, nutrient load. Your soil will be depleted and trying to immediately refill the bucket isn’t the best approach. Start slow on your nutrition and build it back up.

There will always be extremes that lie far outside of normal, but the above steps can help even in heavier rain periods that don’t over saturate the soil. We are all just playing a game with the weather and it’s up to us as operators to make the best decisions for our businesses, our customers lawns, and for the soil, as we can when mother nature is holding all the aces.

Lawncology YouTube Channel

Lawncology® YouTube (13:47) “Soil Test Readings, The B.A.B.E Principal”

What’s up everybody! Back from my week in Florida playing with my kids and teaching CEU’s for the FPMA. It was fun to be back in the teaching saddle and running through some of my favorite topics in a classroom. This particular lesson was about easily interpreting soil tests and seeing where improvements can be made with simple observations. The tests you see here in this study were from ….