Buckwheat cover cropping for vegetables
Buckwheat can be used as a cover crop to improve soil health and fight weeds in any six to seven week window in vegetable production systems. Now (mid-May) is a good time to sow buckwheat in fields that will be planted with a late vegetable crop. Buckwheat is also a good choice following early-harvested vegetable crops like peas and before winter grains. A new Cornell University handbook (http://www.nysaes.cornell.edu/hort/faculty/bjorkman/buck/Buck.html ) provides practical information on the use of buckwheat in several cropping systems.
Why plant buckwheat?
Buckwheat is an ideal smother crop for weed suppression. Its rapid growth blocks sunlight and prevents weeds from establishing successfully. In idle fields with high weed pressure, two successive plantings of buckwheat can suppress annuals and weaken tough perennial weeds like quackgrass. Our recent studies have shown that incorporated residues of buckwheat can selectively suppress germination of several weed species including redroot pigweed; certain vegetables, including peas can also be inhibited, but only when planted into fresh residue. Buckwheat is also reported to extract phosphorous and improve soil aggregation through secretions from its fine roots, mellowing the soil for establishment of subsequent crops. In addition, many beneficial insects are attracted to buckwheat. Among the 19 plant species examined by MSU entomologists, buckwheat ranked fifth in the number of beneficial insects attracted (http://nativeplants.msu.edu/fagesc.htm).
Buckwheat is sensitive to frost, so it cannot be planted as early or as late as alternatives like oats or mustards. Buckwheat is also sensitive to several herbicides including atrazine, Pursuit, Sandea and Reflex and therefore cannot be successfully planted following crops using those herbicides. Some growers report problems with volunteer buckwheat in subsequent crops if mowing and incorporation is delayed.
Drill at 50 lbs/acre at one inch or less for most effective establishment. If broadcasting, use 70 lbs/acre and shallow incorporate. To reduce risk of buckwheat seed production, mowing and incorporation should occur within 10 days of flowering (about 40 days after sowing). Buckwheat does well on a wide range of soil types and can perform well on infertile soil, but does not tolerate excessively dry or wet conditions very well.
Dr. Brainard’s work is funded in part by MSU‘s AgBioResearch.