More phosphate fertilizer will go onto the farms of Iowa this spring than ever before. Iowa farmers want to produce abundantly for their nation and her allies to help win the war. Farmers are asking, “Where shall I apply phosphate fertilizer ? Can I get my soil tested by a chemical means and know where to put the fertilizer to get the most returns from it?”
Allaway, W. H.
"Can You Trust Phosphorus Soil Tests?,"
Farm Science Reporter: Vol. 3
, Article 2.
Available at: http://lib.dr.iastate.edu/farmsciencereporter/vol3/iss1/2