ILLUSTRATIONS 



PLATES 



Nitrates, Nitrification, and Bacterial Contents op Five Typical Acid 

 Soils as Afpected by Lime, FERTn.izER, Crops, and Moisture 



Plate i. Representative plates from i to 400,000 bacterial dilution of acid page 

 yellow silty clay, cropped and held under optimum moisture conditions: 

 A. — ^Aerobic plates, untreated. B. — Aerobic plates, treated with 2 tons 

 of calcium carbonate. C. — Aerobic plates, treated with complete ferti- 

 lizer. D. — Aerobic plates, treated with complete fertilizer and 2 tons of 

 calcium carbonate. E. — Aerobic plates, treated with complete fertilizer 

 and 6 tons of calcium carbonate 42 



Plate 2. Representative plates from i to 400,000 bacterial dilution of acid 

 whitish silt loam and acid brown silt loam cropped and held under opti- 

 mum moisture conditions: A. — Aerobic plates, acid whitish silt loam, 

 untreated. B. — Aerobic plates, acid whitish silt loam, treated with 3 tons 

 of calcium carbonate. C. — Aerobic plates, acid whitish silt loam, treated 

 with 500 pounds of acid phosphate. D. — Aerobic plates, acid brown silt 

 loam, untreated. E. — Aerobic plates, acid brown silt loam, treated with 

 3 tons of calcium carbonate. F. — Aerobic plates, acid brown silt loam, 

 treated with 500 pounds of acid phosphate. G. — Anaerobic plates, acid 

 browTi silt loam, untreated. H.— Anaerobic plates, acid brown silt loam, 

 treated with 3 tons of calcium carbonate. I. — Anaerobic plates, acid 

 brown silt loam , treated with 500 pounds of acid phosphate 4a 



Plate 3. Representative plates from i to 400,000 bacterial dilution of acid 

 black peaty sand, cropped and held under optimum moisture conditions: 

 A. — Aerobic plates, untreated. B. — Aerobic plates, treated with 2 tons 

 of calcium carbonate. C. — Aerobic plates, treated with complete ferti- 

 lizer. D. — Aerobic plates, treated with complete fertilizer and 2 tons of 

 calcium carbonate. E. — Aerobic plates, treated with complete fertilizer 

 and 6 tons of calcium carbonate. F. — Anaerobic plates, treated with 

 complete fertilizer. G.— Anaerobic plates, treated with complete ferti- 

 lizer and 2 tons of calcium carbonate. H. — Anaerobic plates, treated with 

 complete fertilizer and 6 tons of calcium carbonate 42 



Plate 4. Representative plates from i to 400,000 bacterial dilution of acid 

 dark-brown peat, cropped and held under optimum moisture conditions: 

 A. — Aerobic plates, untreated. B. — Aerobic plates, treated with 2 tons 

 of calcium carbonate. C. — Aerobic plates, treated with 20 tons of cal- 

 cium carbonate. D. — Anaerobic plates, untreated. E. — Anaerobic 

 plates, treated with 2 tons of calcium carbonate. F. — Anaerobic plates, 

 treated with 20 tons of calcium carbonate 4a 



Plate 5. Representative plates from i to 40,000 bacterial dilution of acid 

 yellow silty clay kept at different moistiu-e contents: A2. — Aerobic plates, 

 from soil kept one-half saturated. Ho. — Anaerobic plates, from soil kept 

 one-half saturated. Cj. — Aerobic plates of carbon-dioxid-siu-viving organ- 

 isms from soil kept one-half saturated. A3. — Aerobic plates from soil kept 

 fully saturated. H3. — Anaerobic plates from soil kept fully saturated. 

 C3. — Aerobic plates of carbon-dioxid-surviving organisms from soil kept 



fully saturated 42 



(V) 



