Cover Crop Updates
The benefits of incorporating cover crops [CC] into Midsouth soybean production systems are well-documented on this website and in articles in other venues. The following points are gleaned from published reports of results from CC research [“What is the ideal cover crop planting window for optimal establishment and cash crop yield” by Nathan Johanning of the Univ. of Illinois (results are preliminary and the research is ongoing) and “Rye planting date impacts biomass production more than seeding rate and nitrogen fertilizer” by Balkcom, Read, and Gamble] that was conducted in Illinois and Alabama, respectively.
• Management is the key to maximizing cover crop benefits, and the management factors that can best be controlled by a producer are CC species, its/their seeding rate(s) and date, and the time of CC termination.
• The components of blends or CC species mixtures likely will have different “best” seeding dates and termination dates.
• Results reported from both studies indicate that an October seeding date is best regardless of the CC species. Earlier seeding of both grass and legume CC’s can result in more reliable establishment of the CC and greater CC biomass at termination.
• Cereal rye should be seeded at rates of 30-60 lb/acre before corn in a corn-soybean rotation since the biomass produced from this seeding rate can be as great as that from higher seeding rates.
• In the Alabama studies, total biomass produced by a cereal rye CC decreased with later planting dates that ranged from late October to early December.
• In the Illinois study, balansa clover produced more biomass than crimson clover.
• The soil benefits derived from incorporating CC’s into a production system are maximized when a reduced tillage system is used.
• Planting early regardless of U.S. region is critical for maximizing CC benefits compared to other inputs such as seeding rate.
Click here for a Miss. Crop Situation blog article titled “Cover Crop Planting Methods and Seeding Rates” by Dr. Erick Larson that provides suggested seeding rates for various CC’s that may be planted alone or in a blend in the Midsouth.
Planting any CC species early in a Midsouth soybean-corn rotation will not be a problem since most of the corn crop and the majority of the soybean crop will have been harvested by mid-October. However, both corn and soybeans have optimum early planting dates that will generally be earlier than the optimum termination date of most CC species. Thus, producers who use CC’s should select the appropriate species [grass before soybean and legume before corn] that has an optimum termination date that is closest to the optimum planting time for the following summer crop.
Balansa clover [click here and here for details about this clover] was used/is being used as a legume CC in the Illinois study. Major points to consider when selecting this clover as a CC species follow.
• It is touted to have superior reseeding potential compared to other legumes, including crimson clover. It can reseed for several years from a single seed crop due to its relatively high amount of hard seed.
• Established stands tolerate waterlogging and soils that are poorly drained.
• Its seed are small, so planting only a small amount of seed will give a dense stand. The small seed must be planted shallow.
• Balansa clover is less likely than crimson clover to host root-knot nematode, and it is not a host for soybean cyst nematode.
• The hollow stems of this species allow it to be terminated with roller/crimpers if a height >14 in. has been attained.
• It is touted to be the most versatile of the annual clovers since it will tolerate myriad adverse soil conditions.
• Cost of balansa clover seed [$2.30/lb] is greater than that of other clover species [e.g. crimson clover–$1.40/lb]. However, it should be sown at a much lower rate [6-8 lb/acre vs. 12-20 lb/acre for crimson clover in a CC monoculture], so it will be more economical to use as a CC.
Click here to access a Cover Crops White Paper that is posted on this website, and here to access CC variety trial results from several southern states.
Composed by Larry G. Heatherly, Nov, 2024, larryh91746@gmail.com