“I’d like you to come out here and tell me why these two fields we’ve farmed for the past 38 years are suddenly too wet to work anymore.”
This type of call has become all too common at Soil and Water offices across the Midwest in the past few years. Record precipitation and its subsequent fallout is something we’re likely to be dealing with for a long time. Weather data shows that we’ve been in a long-term trend toward “wetter and warmer” for decades.
As climatologists watch the big picture change, those of us who work close to the land see the effects on a smaller, more personal scale. Folks don’t call us asking what they can do about the weather, they ask what they can do on their own farms to adjust and compensate for it.
Last spring’s relentless rainfall played havoc individual fields. Low areas were inundated repeatedly, and high ground suffered the erosive consequences of one heavy rainfall event after another. In a simpler world, one would imagine that when the rain stops, the waters recede, and things dry up a bit we can simply pick up where we left off.
Unfortunately, things don’t always work that way. Fully saturated ground is far more susceptible to erosion, especially when unprotected by cover or even residue from the previous fall’s harvest, than ground that has had a chance to dry out between wet periods.
The punch of water from a storm carries silty fines off on their way immediately, and heavy rains working on already wetted soils transport larger particles; sand, gravel, shale, into the system to be deposited downslope or downstream.
Tough to detect
In an area like Holmes County where I work, even heavily forested hillsides flush debris to flat, silt loam valley floors where it falls out — sometimes in bars and low rises — that can alter overland drainage overnight. It doesn’t take much of this deposition to trap water on a dead flat field, and very often its tough to detect a rise with the naked eye — even on a field that you’ve farmed for 40 years.
The first of the two fields mentioned at the beginning of this column found itself in just such a situation. An almost imperceptible low rise had reached a critical point where surface flow could no longer make it “over the hump” without dropping further outwash in the same spot and trapping water behind in a growing pool. Caught early, this hump could be blended with some creative, directional tillage. A laser level could come in awfully handy in the diagnosis and remedy. Your local SWCD office may be able to help in that regard.
The second field was a victim of outwash deposition as well, but it manifested in an entirely different way. Here, the field had been systematically tiled perhaps 70 years prior and the low-slope of the clay tile main had finally clogged with silt to the choking point. With nowhere else to go, the pressurized storm flow blew out the main resulting in a gurgling flow that saturates surrounding soil even in the smallest rain events. Another relatively simple fix — if one can only find a period dry enough to get machinery out to site.
Now is a fantastic time to look for problems and plan solutions. Your local SWCD should be happy to help with advice.
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