PLATE V. 



Fig. 1. — Soil from nitrification plots. 



(1) Untreated. 



(2) Limed. 



(3) Ammonium sulfate, 4.3 grams. 



(4) Ammonium sulfate, 4.3 grams, limed. 



(5) Dried blood, 7.0 grams. 



(6) Dried blood, 7.0 grams, limed. 



Fig. 2. — Soil from plot 4, source of nitrogen test. 



(1) Untreated. 



(2) Limed. 



(3) Ammonium sulfate, 4.3 grams. 



(4) Ammonium sulfate, 4.3 grams, limed. 



(5) Dried blood, 7.0 grams. 



(6) Dried blood, 7.0 grams, limed. 



