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Does Alfalfa or Comfrey Make a Better Cover Crop?

From Ecology Action

Alfalfa (medicago sativa)

 

Question:  Between alfalfa or comfrey, which would you recommend for producing the most biomass and accumulating the most minerals for use as compost material?.

Answer: Both alfalfa and Russian comfrey are good, but there are differences.Russian Comfrey (Symphytum x uplandicum)

  • Unimpeded alfalfa can put down roots up to 125 feet, whereas comfrey will more typically be in the 8 foot range.
  • Alfalfa is nitrogen fixing and comfrey is not.
  • Alfalfa can produce more than twice the dry biomass as comfrey, which has a higher water percentage in its leaves.
  • Both concentrate nitrogen, calcium and trace minerals.
  • In addition, alfalfa contains a substance that can increase the yields of other crops, once the dry material from the alfalfa has been composted, and that compost is added to the soil the other crops are planted in.
  • Of all of the comfrey varieties, Russian comfrey is one of the more prolific ones.

 

 

NOTE: Alfalfa image from http://en.wikipedia.org/wiki/File:Medicago_sativa_02_bgiu.jpg; Russian Comfrey image from http://en.wikipedia.org/wiki/File:Russian_comfrey_close_800.jpg