How much nitrogen does a legume green-manure crop contribute to the soil? What influence does it have on the yields of the following corn crop? How does this compare with side-dressed applications of fertilizer nitrogen?
Stickler, F. C.; Johnson, I. J.; Shrader, W. D.; and Thompson, H. E.
"Green Manures or Fertilizer Nitrogen for Corn?,"
Iowa Farm Science: Vol. 13
, Article 4.
Available at: https://lib.dr.iastate.edu/farmscience/vol13/iss11/4