2>^ 



Journal of Agricultural Research 



Vol. XVI, No. 2 



The yellow silty clay containing 0.07 per cent of nitrogen and the 

 black peaty sand containing 0.40 per cent of nitrogen received the same 

 lime and fertilizer treatments, but gave quite different crop yields, ni- 

 trates, and nitrification. These variations can not be entirely correlated 

 with changes in soil acidity. On the yellow silty clay it took both lime 

 and fertilizer to give a markedly increased nitrifying power, while on the 

 black peaty sand, of higher initial nitrifying power, lime gave the large, 

 increased nitrifying power. 



The whitish silt loam containing 0.12 per cent of nitrogen received 

 the same lime and acid-phosphate treatment as the brown silt loam 

 containing 0.22 per cent of nitrogen. Lime increased nitrification on 

 both these soils more than acid phosphate did. 



SOIIv MOISTURE IN RELATION TO NITRATES AND NITRIFICATION 



In order to ascertain what effect keeping soils at different moisture 

 contents without crop would have on the nitrates present in the soil and 

 nitrification tests, samples were drawn from a series of pots where each 

 of the five acid soils had been kept at different moisture contents. The 

 nitrates present in the soils after standing 10 months with specified 

 moisture contents are given in Table II. 



Table II. — Effects of variable moisture on nitrates and nitrification of five typical 



acid soils 



Acidity." 



Kind of soil and moisture treatments 



YELLOW SILTY CLAY. 



One-half 3, 07 



Full \ I, 740 



WHITISH SILT LOAM. 



One-fourth . 

 One-half. . . 

 Full 



BROWN SILT LOAM. 



One-fourth . 

 One-half. . . 

 Full 



BLACK PEATY SAND. 



One-fourth . 

 One-half. . . 

 Full 



DARK-BROWN PEAT. 



One-fourth 



One-half 1 2, 700 



Full 



After in- 

 cubation. 



P. p. m. 

 19 



82 

 128 



100 

 122 



Increase 

 on incu- 

 bation. 



328 



190 



O 



214 

 766 



P. p. m. 



-5 

 o 



-165 



-197 



o 



-125 



o 



36 



148 



o 



Ratio be- 

 fore and 

 after in- 

 cubation. 



126 



166 



58 



265 

 261 



43 

 166 



83 



o Both methods are expressed in calcium-carbonate requirement per million. 



