Kenny: farm manager and co-instructor of my class.
Thanks to hurricane Irma it has been to wet this last week and a half to do much with our plots so we’ve been in the classroom.
Since we were stuck inside, Kenny showed us a presentation on their own problems they had with their spinach crop from the last semester.
As it turned out, one of the cover crops( Sorghum x Sudan grass) he had added the previous year is negatively allelopathic. Meaning it secretes a chemical that negatively affects some other plants.
It caused exceedingly stunted root growth in both spinach and romaine lettuce. It did not effect the kale and it also significantly reduced the doc weed population( doc and kale were field but not lab tested .)
The conclusion is that Sorghum x Sudan would be a good cover harvest( offer lots of organic matter and may be a bio-herbicide ), but merely in plants, such as kale, that are not affected by its allelopathy.