no 
Journal of Agricultural Research 
Vol. II, No. s 
O / 2 
MONTHS 
QR£EN 
VETCH 
0 _ / 2 , 
MONTHS 
GREEN 
EARLEY 
0/2 
0 / 2 , 
MONTHS MONTHS 
SrfRLEY 
STRAW 
CHECK 
SO/E 
Fig. 6.—Diagram showing effect upon total nitrogen, not in¬ 
cluding nitrate nitrogen, in samples of California soil of 
additions of 2 per cent of green vetch, green barley, and 
mature barley straw. 
VETCH EARLEY SO/E STRAW 
Fig. 7.—Diagram showing effect of additions of 2 per cent of 
green vetch, green barley, and mature barley straw upon 
the nitrifying power of samples of California soil. 
