34 



Journal of Agricultural Research 



Vol. XVI. No. 2 



lime nor complete fertilizer alone had any great influence on bacterial 

 numbers, while complete fertilizer with 2 tons of lime more than doubled 

 the bacterial index (sum of aerobes and anaerobes) of the soil. Six 

 tons of lime with fertilizer did not increase the bacterial index as much 

 as the 2 tons with fertilizer. 



Tabi,E III. — Effects of lime and fertilization on bacterial content of five typical acid soils 



Millions of bacteria per 

 gram of dry soili 



Kind of soil and treatment per million 

 pounds of soil. 



Air incu- 

 bation. 



Hydrogen 

 incubation. 



Bacterial 

 index." 



Increase of bacterial 

 index due to — 



Calcium 

 carbonate. 



Fertilizer. 



YELLOW SILTY CLAY. 



No treatment 



2 tons of calcium carbonate , 



Nitrogen, phosphorus, potassium « . . 

 Nitrogen, phosphorus, potassium, c 



2 tons of calcium carbonate 



Nitrogen, phosphorus, potassium, c 



6 tons of calcium carbonate 



WHITISH SILT LOAM. 



No treatment 



3 tons of calcium carbonate . . 

 500 pounds of acid phosphate , 



BROWN SILT LOAM. 



No treatment 



3 tons of calcium carbonate . . . 

 500 pounds of acid phosphate . 



BLACK PEATY SAND. 



No treatment 



2 tons of calcium carbonate 



Nitrogen, phosphorus, potassium b 

 Nitrogen, phosphorus, potassium, 



2 tons of calcium carbonate 



Nitrogen, phosphorus, potassium, 



6 tons of calcium carbonate 



DARK-BROWN PEAT. 



No treatment 



2 tons of calcium carbonate . . 

 20 tons of calcium carbonate. 



Average . 



^3. 010 

 3. 046 

 3.027 



7.605 



5- 244 



5.021 



14. 810 



5-531 



9. 904 

 23. 921 

 II. 164 



3. 146 

 8.386 

 2.813 



10. 583 



16. 037 



I- 554 



3. 420 



91. 846 



12. 109 



o. 100 

 .381 

 . 000 



. 000 



. 000 



1-545 

 .898 

 . 000 



2- 556 

 2.714 



I- 154 



1. 617 



2. 907 



.099 

 I. 760 



■997 

 I. 440 



II. 752 



1-585 



3. no 



3-427 

 3.027 



7.605 



5- 244 



6.566 



15. 708 



5- 531 



10. 093 

 26. 477 

 13- 878 



4.300 



10. 003 



5.720 



17- 797 



2- 551 



4. 860 



103. 598 



0-317 



4-578 

 2. 217 



4. 962 

 12. 077 



13- 694 



2.309 

 loi. 047 



15-874 



-0.083 

 4.178 



.679 



a Sum of air and hydrogen counts. • i .-, • 



i Average of five plates. No count indicates no colonies on plates from i:.4oo,ooo bacterial dilutions. 

 <^ Chemically pure salts: 91 pounds of ammonium nitrate, 72 pounds of ammonium phosphate, and 100 

 pounds of potassium phosphate on yellow silty clay. No ammonium nitrate was used on black peaty sand . 



Lime more than doubled the bacterial indexes of the whitish silt and 

 brown silt loams. Acid phosphate decreased the anaerobic counts of 

 the whitish silt loam enough more than it increased the aerobic con- 



