Renewable Farming

“Now all we need is a fence and cows” to harvest this massive cover crop

“This part of our garden was solid Canadian thistle this spring,” Howard Vlieger said in a message which accompanied the photo at the bottom of this report. Howard’s home and farm is in Sioux County, northwestern Iowa.

August 26, 2018 — The transformation from thistles to a thick cover crop on this patch occurred with the aid of a nonselective herbicide which Howard has been developing over the past several years. He’s cooperating with an overseas R&D team, plus U.S. scientists.

Howard Vlieger in cover-crop experimental patch

Howard details the season’s steps toward this test result:

“Last fall I seeded cereal rye in this area.”

During this spring’s rainy weather, thistles surged ahead of the cereal rye, signaling that both calcium and sulfur were deficient in this soil.

When the thistles were blooming, Howard pushed his skid loader bucket low over the patch, doing a simulated crimping of the cereal rye. However, the rye wasn’t mature enough for crimping to kill it. Cereal rye must be into its reproductive stage before crimping it prevents regrowth. 

Howard reports that after crimping, “We did a burndown with our nontoxic product, as flattening it wasn’t going to hold due to the rye’s premature stage.”


“We let the second flush of thistles grow, and did another burndown.

“We let the third flush of thistles emerge, and did a final burndown.”

Three times during this growing period, Howard applied S04, a pelletized gypsum from Calcium Products Inc., at the rate of 350 pounds per acre for a total of 1,050 ponds per acre.

“After the third burndown, we seeded an 11-way cover crop mixture: two types of brown midrib sorghum, pearl millet, two types of cow pea, African cabbage, Sun hemp, turnip, buckwheat, soybean and tillage radish.

“As of the end of August, I can’t find one single Canadian thistle in this area.”

Here’s the bottom line of this experiment: “There is no doubt in my mind that our burndown product has a very positive effect on the microbiome of the soil.

Over the past two years, the burndown product has been lab-tested at a highly capable facility for any impact on soil organisms. The result: It shows positive stimulus of beneficials like pseudomonas, and constrains fusarium pathogens. There’s further detail on this experimental product in our previous report, at this link.

Howard projects that the herbicide’s EPA registration could be approved for non-crop uses such as parks and recreation areas in late 2019. The next objective will be clearance for specialty crops sometime in 2020. After that, he anticipates a broader approval for field uses, such as terminating cover crops.

Overview of cover crop test plot