In fall 2021, Alabama Extension and Auburn University researchers planted cover crop demonstrations on five Alabama farms in Autauga, Geneva, Henry, Lawrence and Lee counties. Each demo was panted during the last two weeks of October with a no-till drill. Treatments are shown in table below.
Cover crops were not fertilized, except at the Geneva County location, where chicken litter was applied in early spring. The highest biomass-producer was ‘FL401’ rye, which produced an average of 5000 pounds per acre of biomass across locations. The highest biomass for a legume cover crop was ‘Dixie’ crimson clover, but ‘AU Merit’ hairy vetch produced more biomass earlier in the season and was great for smothering weeds. Researchers outline some “lessons learned” from these demos below.
1. Early maturing varieties shine in a short growing window.
These photos were taken on March 3, 2022 in Henry County. Across locations, ‘FL401’ produced over 5000 pounds of biomass and ‘Wrens Abruzzi’ produced approximately 3000 pounds of biomass at termination.
These photos were taken on April 7, 2022 in Geneva County. At cover crop termination, these varieties produced similar biomass. However, ‘Legend’ may be an ideal oat variety for farmers with a short growing window.
Cover Crop Biomass Levels
|Treatment||Dry Weight Biomass|
|'Wrens Abruzzi' Rye - 90 lbs/acre||2980|
|'Wrens Abruzzi' Rye - 60 lbs/acre||3200|
|'Wrens Abruzzi' Rye - 30 lbs/acre||3160|
|'FL401' Rye - 30 lbs/acre||5370|
|'Trical 342' Triticale - 30 lbs/acre||2640|
|'Cosaque' Oat - 30 lbs/acre||2640|
|'Legend' Oat - 30 lbs/acre||2810|
|'Wyo' Winter Pea - 40 lbs/acre||1800|
|'AU Merit' Hairy Vetch - 10 lbs/acre||2520|
|'AU Sunrise' Crimson Clover - 10 lbs/acre||2190|
|'Dixie' Crimson Clover - 10 lbs/acre||3140|
|'Wrens Abruzzi' Rye + 'Dixie' Crimson Clover Mix||3160|
2. Low seeding rates of small grains can be high biomass producers.
It is tough to tell a difference between rye planted at 30 pounds per acre (left) and 60 pounds per acre (right) in photos taken in Lee County on April 8, 2022. Researchers planted ‘Wrens Abruzzi’ cereal rye (one of the most popular cover crops in Alabama) at three seeding rates (drilled): 30, 60, and 90 pounds per acre.
Regardless of the seeding rate, these cover crops produced approximately 3000 lbs of biomass at termination. This suggests that producers can save money on seed costs without sacrificing biomass production.
3. Patience is a virtue when it comes to legumes.
The photo on the left was taken on March 1, 2022 in Autauga County. This spotty stand of ‘AU Sunrise’ crimson clover (planted at only 10 lbs per acre) seemed like it would be a disappointing cover crop at termination. However, by April 7, it had turned into a beautiful stand of blooming crimson clover.
This photo was taken on March 28, 2022 in Lawrence County. ‘AU Merit’ hairy vetch also took a while to get started, but it was a high-biomass producing legume cover crop across locations. The abundant growth of hairy vetch smothered winter weeds at each location.
Cover crop demonstrations were funded by the NRCS-CIG Future of Farming Project.