"Incredible soil erosion this spring" was an underlying theme at the tillage demonstration day sponsored on August 5 by the Manitowoc County Forage Council.
That phrase was used by Tony Smith of the county's soil and water conservation department but several other speakers echoed that terminology to describe what happened in numerous area fields in early June shortly after annual crops were planted or had emerged.
Smith reminded farmers that continued eligibility for Wisconsin's Farmland Preservation program of tax credits depends on meeting conservation standards on soil erosion. He suggested that vertical and reduced tillage practices are a good option for meeting that goal but added that improving soil structure and health will result in better infiltration and less runoff of surface water during periods of heavy rainfall.
Addressing the latter point was Matt Rataczak of the Manitowoc County Natural Resource Conservation Service office. With soil taken from within the winter wheat field where the tillage day was held and from an adjacent fenceline where the soil has not been tilled for a long time, he poured water into tubes containing the two soil samples.
Water penetrated the soil from the fenceline far more quickly and the period for which water remained on the surface of that soil was significantly less than on top of the soil taken from the tilled field.
Regarding tillage, area crop consultant Steve Hoffman pointed out that soil loosened by tillage to a depth of about 5 inches is very vulnerable to erosion during the heavy rains that fell in the area this spring. He recommended tillage that puts the soil into a uniform condition to a depth of 11 inches as a way reduce a repeat of the massive erosion that occurred this year.
Rataczak noted that the pulverizing of soil to a depth of a few inches in order to create a good seedbed creates a high risk of soil erosion. Hoffman suggested an evaluation of the differences between vertical and horizontal tillage methods on how they affect soil erosion.
The planting of cover crops both to control soil erosion to upgrade soil health, structure, and fertility is an approach being taken and evaluated by Manitowoc County soil and water conservation department resource conservationist and landowner Bruce Riesterer.
At the tillage day, Riesterer announced his plan to continue the growing of cover crops with an anticipated seeding of mix of nine species for a cost of less than $30 per acre. The mix will include winter peas, ryegrass, safflower, sun hemp, sudangrass, radish, and turnips, he said.
Riesterer will not be harvesting the forage. In the spring of 2015, he intends to kill the ryegrass that survives the winter with a herbicide and then plant soybeans.
Looking ahead in a different realm, Manitowoc County Extension Service dairy agent Scott Gunderson cautioned farmers about the "hard soil" that predominates in many of their fields today and about the accompanying risk to the environment when applying liquid manure on those fields.
Gunderson cited the prohibitions in place about such applications within 300 feet of a river or stream or 1,000 feet of a lake and the importance of incorporating liquid manure within 48 hours of application. As another safety practice, he suggested tillage around the edges of fields before the liquid manure is applied.
One attraction at the field tillage day was the digging of a soil pit to demonstrate the soil profile of the Kewaunee silt loam and heavy clay. The pit, to a depth of about 4 feet, was dug at the field's transition zone between where corn and alfalfa were grown in 2013. The winterkill of alfalfa in the lower portion of the field forced an unplanned change to grow corn there instead.
Rataczak used the pit to point out features of the soil profile such as the depth to which plant roots grew, a hard plow pan layer of soil, and the remaining signs of a tillage with a subsoiler to a depth of about 18 inches quite a number of years ago.
What was missing in the soil profile in the pit was much evidence of an earthworm population, which Rataczak suggested would be 10-20 worms per cubic foot as one indication of healthy soil. He invites interested persons to contact him to learn more about those and related topics.
During his presentation, Rataczak referred several times to a recent trip he made to Ohio, where he asked questions about the links between manure applications, soil health, and protection of soil and water resources but got little response because the availability of livestock manure is limited in that area.