Jefferson Co. Soil Builders explore new management practices
MILFORD – The new Jefferson County Soil Builders group is working to implement best management practices to reduce soil erosion and phosphorus runoff, increase soil organic matter and improve soil health.
The farmer-led coalition shared their ideas during the organization’s first field day last week, highlighting successful conservation and farming practices.
Jamie Patton was the guest speaker for the organization’s field day hosted by several farms near Milford. Patton, a senior outreach specialist with the University of Wisconsin‒Madison & Extension Nutrient and Pest Management Program, compared the differences in soil due to the varied management practices.
Host farms followed a variety of practices including conventional, conservation tillage and no-till. Some fields had cover crops established for several years. Others have never utilized cover crops.
Speaking from the bottom of soil pits dug in two fields with different land use histories, Patton highlighted how soil characteristics can change with management over time and how these soil characteristics can impact plant growth, rainwater infiltration and soil erosion.
The first pit was actually dug on what had been a fence line for many years. Visitors observed that the ground was higher in the area, caused by eroded soil washing into the fence line area over the years and by the fact that there was no compaction from wheel traffic.
One of the primary indicators of a healthy soil system is its organic matter content.
So, how might farmers increase the organic matter of their soils? The key is to increase the amount of organic material being deposited in the soil system, while simultaneously decreasing its loss through erosion and decomposition. One practice to increase the amount of organic matter being added is through the use of cover crops
The cover crop’s contribution to soil organic matter is two-fold.
First, the crops’ above ground plant matter helps protect the soil from raindrop impact, runoff and erosion, while also providing a habitat for beneficial insects and contributing to the soil organic matter content as it decomposes. Second, the cover crop’s roots create pore channels as they penetrate the soil, helping to reduce compaction and improving water and air movement into the soil.
“The plants actually give up a lot of sugar to feed the soil life,” she points out. “They also help us aggregate the soil.”
She noted the difference between the two soil pits. The one on the fence line that had a cover crop established on one end and a lightly tilled field on the other had moist dark colored soil. Roots and worm channels were visible throughout.
The one in the conventional tilled field was dry on the top and there was an abrupt change in soil texture indicating the plow line.
“Any time there is an abrupt change in the texture and color of the soil there will also be rooting issues,” she said.
Patton points out that soil scientists are predicting this could be a drought year and she said crops established on the looser healthier soil will have better access to water than those planted into harder ground.
“Any time there is a plate from water infiltration there will be a problem getting corn to stand and moisture to the roots,” she said. “If you can keep worm channels open roots have a path to follow and go down for moisture with less resistance.”
As the cover crop roots grow, and as they die and decompose, they add various organic materials to the soil, materials that increase the soil’s organic matter content, as well as serve as a key food source to the soil microbial population, a population that helps maintain soil fertility, soil porosity and water quality.
Visitors also observed bright orange lines throughout the soil profile.
Patton explained that these lines are where roots went down both vertically and horizontally, carrying oxygen with them. When combined with the iron in the soil the rust orange color appeared.
To reduce soil organic matter loss through erosion and decomposition, many farmers are turning to no-till systems, leaving “the tillage work” to the plants and soil biology. In a no-till system, farmers do not use tillage equipment to turn under crop residues and prepare a seedbed for planting. Instead, planting operations are carried out in the residue remaining from the prior year’s cash crop and/or cover crops.
By not tilling the soil, remaining plant residue protects the soil surface from raindrop impact and reduces runoff, thereby increasing water infiltration and reducing erosion.
Additionally, reducing tillage helps preserve soil organic matter by limiting unnatural introductions of oxygen into the system, introductions that can over stimulate the decomposition process. Soils managed under no-till also often benefit from increased soil biological activity, increasing the overall health of the soil.
Also speaking at the event was Scott Schultz who said he stumbled on cover crops when he custom-baled a mix of clover and wheat straw for an area farmer. He realized at that time the benefit of the clover and straw as a feed for livestock.
Dean Weichmann, chair of the new Jefferson County soils group, said he has been practicing no-till farming for more than 30 years. In more recent years he has also been establishing cover crops and likes to plant into green standing covers.
In the past he has sprayed to kill off the cover after the new crop is established but this year he purchased a crimper that he will use to roll the established green cover after planting the new crop. Timing is important, he points out.
Rolling must be done in the boot stage for cereal rye when the stem is the most brittle. The soybeans should be at the V2 stage. If crimping is delayed until the V3 stage there will be some damage to the soybeans. That’s why planting into the biomass before the rye is at the boot stage is dangerous because if planting is done too early the beans may be too big before the rye is ready for crimping.
Brendon Blank who farms in Jefferson County and has also been selling cover crop seed and helping educate farmers about covers for many years said, “When you plant into residue it must be either completely green and alive or completely dead. Otherwise as it decomposes it will interfere with growth of the new plants.”
He added, “Planting into standing, tall rye may seem different but it is actually easier than planting into residue. It’s easier than you might think.”