Iowa Soil Health Workshop Planned for August 4th
Iowa Soil Health Workshop Planned for August 4th
Topics will include fertility tests, cover crops, and evaluating soil health with a microscope
Iowa Soil Health Workshop Planned for August 4th
Topics will include fertility tests, cover crops, and evaluating soil health with a microscope
This year’s Weed Science Field Day will be held on Thursday, July 14 at the Iowa State University Curtiss Farm, Ames, IA.
Although the 2022 cold and wet spring has significantly delayed corn and soybean planting in Iowa, we are still on track to demonstrate corn and soybean research plots on the Field Day.
The Field Day will include an update on corn and soybean herbicide programs, status of herbicide resistance in waterhemp in Iowa, cereal rye cover crop for weed control, and demonstrations of novel harvest weed control methods including chaff lining and seed destructor.
Downed corn from the August 10 Derecho, which affected millions of acres in Iowa, will contribute to significant volunteer corn populations in crop fields in 2021. Volunteer corn ranging from 800 to 13,000 plants per acre can cause yield losses up to 54% in soybean and up to 13% in corn, according to the research conducted at SDSU, UMN, and UNL. In unharvested corn fields, establishment of 1% of the corn seed present would result in volunteer corn populations of more than 100,000 plants per acre.
One important benefit of cover crops to our production system is providing an alternative selection pressure on weed populations. Cereal rye has the best potential to suppress weeds because it accumulates more biomass than other cover crop species. Weed suppression is closely related to the amount of biomass at the time of termination (Figure 1).
After a fairly long hiatus, a tweet from Corteva has earned a coveted spot in the HOS. This is a tough one since the company has used a farmer’s quote to disregard the principles of integrated weed management, rather than someone in marketing dreaming up an irresponsible advertisement.
Combines are the most important seed dispersal mechanism for weeds in our cropping system. While a small amount of seed may leave the field with grain, most weed seed that enter the combine with the crop are either spread throughout the field or carried to other fields. Harvest weed seed control (HWSC) involves modifying combines to prevent weed seed present at harvest from being added to the field’s seedbank. Waterhemp is the weed likely to drive the adoption of HWSC in Iowa. For HWSC to be effective, waterhemp must retain the majority of seed prior to harvest.
The current approach to weed management in Iowa is at risk due to rapid expansion of herbicide-resistant weeds. In order to preserve the efficacy of herbicides two things must happen: 1) adoption of integrated weed management, and 2) shift the goal of weed management from protecting crop yields to minimizing the size of the weed seed bank. The first requires a shift in behavior, the second a change in attitude.