Iowa farmers are facing the challenges of a third consecutive year of drought conditions in 2023, making the establishment of cover crops a formidable task. With limited rainfall, overseeding cover crops into standing corn and soybean fields has become less viable due to difficulties in seed germination. As a result, farmers are reassessing their cover crop plans for the current growing season.
One key adjustment is to postpone overseeding cover crops, if possible, until favorable rainfall occurs. This delay can increase the chances of successful germination following the rain, improving seed-to-soil contact and offering better protection against seed predators like birds and rodents.
To optimize cover crop establishment in drier regions, drilling seeds following soybean or corn harvest is the preferred approach. This method ensures superior seed-to-soil contact, enhancing the seed's ability to absorb moisture for germination. Even in areas that received some rain recently, additional moisture may still be necessary. However, drilling seeds remains the best strategy in these circumstances.
A secondary option is to shift to winter small grains such as cereal rye, winter wheat, or winter triticale. These grains germinate quickly and can endure cooler temperatures compared to brassica and legume species. They offer the advantage of early spring growth potential, resulting in substantial biomass production.
For those who can drill seeds before October 1, oats present another alternative. This is particularly applicable to fields harvested for silage corn, high moisture corn, or early maturing soybeans. Oats are expected to winter-kill, and for optimal results, consider seeding at a rate exceeding 60 pounds per acre.
Regardless of the timing of cover crop seeding, it is advisable to conduct a bioassay to assess whether any residual herbicides may impact cover crop germination and growth in the fall.
Looking ahead to spring, cover crops can serve as a valuable tool for weed suppression. To effectively control weeds, consider planting at a higher seeding rate, exceeding 70 pounds per acre for most small grains.
Monitoring the U.S. Drought Monitor and tracking rainfall and snowfall amounts is essential. Assess how effectively water is infiltrating the soil for moisture recharge, as opposed to runoff from intense storms or snowmelt on frozen ground. If soil moisture reserves remain insufficient and precipitation patterns indicate a dry spring, early termination of overwintering cover crops may be necessary to prevent early and shallow soil moisture deficits for the 2024 corn and soybean crop.
Photo Credit: gettyimages-mvburling
Categories: Iowa, Crops