Drilling yet another option to seed covers
Editor’s note: This is the last article in a four-part series highlighting different cover crop seeding techniques.
By LIZ JUCHEMS
Earlier in this series, we highlighted three preharvest seeding methods: overseeding, broadcasting and aerial. Another popular method for seeding cover crops is by drilling or planting them after harvest. In fact, the majority of our farmer-partners in our long-term rye cover crop study choose to drill the rye strips and their additional cover crop acres following the harvest of corn or soybeans.
Drilling cover crops allows for uniform seeding depth, good seed-to-soil contact for germination and higher consistency in the stand. It often requires a lower seeding rate, resulting in a lower overall seed cost when compared to overseeding, broadcast or aerial application.
Similar to the other seeding methods, weather plays a large role in establishment and fall growth potential. Because the seeding is completed after crop harvest, the growing-season length following a corn-soybean rotation is fairly short, especially if an early frost occurs.
Cereal rye or other overwintering species are a better fit for drilling cover crops, as they are more tolerant of cold than non-overwintering species that may only have a few growing degree days in the fall before they are terminated.
• Drilling offers uniform seeding depth, good seed-to-soil contact.
• Cereal rye, other overwintering species work well with drilling.
• Tool calculates the total cost of using the cover crop.
Following the combine
Timing can also prove to be a significant challenge for corn-soybean rotations.
Ideally, the drill is following the combine to get the cover crops seeded as soon as the grain crop is removed. For farmers short on labor during harvest, getting the drill out in the field can be difficult. However, if the previous crop is a shorter-season variety, small grain or seed grain, the window for getting the cover crop seeded after harvest is much larger.
If access to a drill is a limitation, check with your local or neighboring county office to see if it has a drill available.
A handful of county soil and water conservation districts in Iowa have purchased grain drills that are available to rent for cover crop seeding in the fall or soybeans in spring. They may also be able to connect you with a local farmer who may be available for custom application.
Iowa Learning Farms and Practical Farmers of Iowa have partnered with Hagie Manufacturing near Clarion, the Iowa State University North Central Research Farm at Kanawha and a farmer-partner site near Eagle Grove to compare different seeding methods, including overseeding above and below canopy, and drilling postharvest.
The project is in its second year of seeding and is collecting fall and spring biomass and crop yields from the sites to measure the effectiveness of the different seeding methods.
Drilling less expensive
Drilling tends to be a low-cost option. Iowa Learning Farms has created the Excel-based Cover Crop Cost Calculator to help farmers calculate and compare the cost of drilling or aerial-seeding cover crops.
The tool calculates the total cost of using the cover crop including seed, application and chemical termination. You can use the calculator for a single cover crop species or up to six species in a mixture. The tool calculates the cost of drilling and aerial application for easy comparison.
Visit extension.iastate.edu/ilf/content/cover-crop-resources to download the calculator and check out the other cover crop resources available.
Juchems is events coordinator for the Iowa Learning Farms.
This article published in the May, 2016 edition of WALLACES FARMER.
All rights reserved. Copyright Farm Progress Cos. 2016.
Photo: Practical Farmers of Iowa