Jan. 13, 1919 Nitrates, Nitrification, and Bacteria of Acid Soils 



31 



clover. This shows that the nitrates present in the soils were greatly 

 influenced by the growing crop. The limed pot in the brown silt-loam 

 series was no exception to this, as the untreated soil on this series grew 

 good clover. With each soil the amounts of nitrates found after incuba- 

 tion were very much greater with lime than without lime, proving that 

 calcium carbonate promotes nitrification in acid soils. As a rule, the 

 less clover there was per pot the greater the ratio of nitrates before 

 incubation to nitrates after incubation. 



Table I. 



-Effects of lime and fertilization on nitrates and nitrification of five typical 

 acid soils 



Kind of soil and treatment per 

 million pounds of soil. 



YELLOW SILTY CLAY. 



No treatment 



2 tons of calcium carbonate . 



Nitrogen, phosphorus, po- 

 tassium c 



Nitrogen, phosphorus, po- 

 tassium , c 2 tons of calcium 

 carbonate 



Nitrogen, phosphorus, po- 

 tassium, 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 po- 

 tassium c 



Nitrogen, phosphorus, po- 

 tassium , c 2 tons of calcium 

 carbonate 



Nitrogen, phosphorus, po- 

 tassium, c 6 tons of calcium 

 carbonate 



DARK-BROWN PEAT. 



No treatment 



2 tons of calcium carbonate . 

 20 tons of calcium carbonate 



Acidity." 



Crop yields.6 



Nitrates. 



Potas- 

 sium 

 nitrate. 



2, 460 

 20 



2, 800 



1,360 



20 



1,380 



460 



20 



460 



I, 800 

 80 



1,760 



40 



Calcium 

 acetate. 



Wheat 



4, 000 

 4, 125 



750 



3,000 



500 



3,000 



3,750 



750 



3>750 



6,750 

 3,500 



6,750 



3,000 



750 



2, 040 35, 000 



I, 260 I27, 500 



100 I 9, 250 



Gni. 



7 

 10 



43 



68 



76 



23 

 40 



23 



19 

 29 

 20 



o. 5 



52 



o 



o. 5 

 48 



Clover. 



Before 

 incu- 

 bation. 



42 



50 



2 

 60 



25 



6 

 16 



103 

 13 



100 



95 



3 



a Acidity determinations were made by Hopkins potassium-nitrate method and C. H. Jones calcium- 

 acetate methods, and expressed in calcium-carbonate requirement per million. 



6 Crop yields are given in grams per pot; average of two pots. 



c 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. 



