Farmer’s report: It’s really wet out there

A story line so good that Hollywood could probably save itself by picking it up for a movie production; Wisconsin barely survived the worst drought it has recently seen, to now being asked to survive one of the wettest springs it has ever seen. ‘But, how wet is it really’ is the question that has been in my head for a while. Certainly, it has rained more than enough. We see just as many unplanted acres as we see corn fields, but does that constitute as evidence for detrimental conditions brought by the weather? After digging into a bit of data the short answer is: yes, and it is worse than you think. Today we will dive into the amount of moisture in our farm fields, and why it hasn’t been easy for our farmers to work with it.

To simplify our discussion on excessive moisture we will look at data collected at the University of Wisconsin Agricultural Research Station in Stratford to provide the context needed to make the information relevant for understanding (looking at a spot with similar soil type and excellent data collection to be comparable to your farm acres). For easier comprehension I am also looking at the time frame of May 1st to June 24th for 2023, 2024, and the normal (the 30 year average) numbers. So when you see me talk about numbers, unless specified to a specific or an alternative date and time, it is referring to our spring season of the 54 days from May 1st to June 24th.

At the Ag Research Station, the total precipitation has been 11.22 inches. If this seems high, you would be correct. This is more than 2.5 inches above normal, and 7 inches more than this time last year. At first it would seem a welcoming sight, considering the drought that sucked the ground water dry last year, but this heavy rainfall has cascaded into more issues in the fields, such as over saturation. The average soil moisture has been recorded at 45% at 4 inch depth, which is considered excessive. So imagine taking a coffee mug and scooping up a cup of dirt; 45% of that mug is just water.

At the Stratford station, the ideal range for silt loam soil is 20-25% moisture, and since May there has not been a day the soil moisture was less than 25%. In fact, the lowest soil moisture was 38%. Basic Soil 101 is that soil should be 50% organic matter (OM), 25% air and 25% water. This means that there is little to no oxygen present below the soil, which leads to more issues than benefits for the fields.

The swelling of water is shifting the dynamics of the biome, making it soil anaerobic. Think of it as a finished basement that stayed moist, and got black mold: instead of a place to have fun, it is a room dead-set to kill you. Anaerobic soil reduces the crop’s efficiency to take in nutrients (up to 1/18th), to respirate, loss of nitrogen, and nonbeneficial bacteria that attacks the crop. It is so prolific it makes the ground even smell different, taking on a rotten-sour smell. When we see firing corn (corn that takes on a pale green color and bright yellow leaves near the base), it isn’t just the loss of nitrogen but also because the crops are unable to fully take in nutrients and respirate.

Evapotranspiration refers to a plant’s ability to release water through respiration and take in water from the ground. This is largely driven by Growing Degree Days or Units (often referred to as GDDs or GDUs) which is a measurement of time and temperature (above 50 F degrees). The sunnier the day, the more GDUs, the more overcast/cooler days you get fewer GDUs. In May, it is often to see 3-9 GDUs accumulated, and as high as 20 on sunny-hot days. GDUs can reflect the pace of the growing season and are used to predict the life cycles of plants and even insects. At the Stratford location the GDU count is 46 units behind the 30 year normal. This indicates that crops that normally can suck a lot of water out of the ground are doing it at a slower pace. In summary; it is gosh-darn wet, and is on pace to be one of the soggiest springs we see in a while. With July around the corner, we should expect to see clearer skies along with lots of heat. A farmer told me the other day “if you are going to keep being frustrated with it, it is just going to beat you down.” The panic buttons have been hit for a while, but for now all we can do is wait to assess the next best approach. But we will save that discussion for next time. I want to thank my friend Jason Cavadini for assisting me in the data collection for today’s article. Sources used: Wisconsin State Climatology Office, National Oceanic and Atmospheric Administration (NOAA), and UW Extension Ag Weather.

THE SOIL

SOUNDOFF

BY

MATT OEHMICHEN AGRONOMIST