54 
Journal of Agricultural Research 
Vol. VII, No. a 
The amounts of nitrate produced are smaller in Group III of Table I 
than in Group I for reasons which are obvious and which have been 
referred to previously. Nevertheless, in spite of the disadvantage which 
the added dried-blood nitrogen creates in this series with respect to the 
relative considerations, about 23 soils, or nearly 50 per cent of the whole 
number, transform more than 10 per cent of the total soil plus dried-blood 
nitrogen into nitrate, and several other soils approach that record closely. 
In five cases more than 20 per cent, of the total nitrogen present is trans¬ 
formed into nitrate. Taken as a whole, therefore, and in spite of the 
large quantities of blood used, the foreign soils must be adjudged efficient 
nitrifiers of dried-blood nitrogen. This is particularly to be kept in mind 
for comparison with data from the California soils. 
Group IV of Table I, which gives the results obtained in the cotton¬ 
seed-meal series, is not strikingly different from Group III, which rep¬ 
resents the dried-blood series. Nevertheless some distinct points of 
dissimilarity between the two require some comment. Thus, it must 
be noted that in the dried-blood series, 34 out of 48 soils produced more 
nitrate nitrogen than they did with the soil nitrogen alone. In the cotton- 
seed-meal series only 26 out of the same total of soils accomplished that 
task. On the other hand, certain soils which induced only losses of 
nitrate nitrogen with dried blood, like the Georgia, Louisiana, and 
South Carolina soils, gave with cottonseed meal increases of nitrate over 
those produced with the soil nitrogen alone. 
The percentage of total nitrogen which is transformed into nitrate in 
the cottonseed-meal series with the foreign soils is not strikingly unlike 
that of the dried-blood series when the soils are regarded as a whole. 
Nevertheless the individual soils show marked differences in the direc¬ 
tion noted. Thus, for example, eight of the soils in the dried-blood 
series transform nothing or less than 2 per cent of the total nitrogen 
present into nitrate, whereas in the cottonseed-meal series no soil is pro¬ 
ductive of no nitrate, and only two fall in the 2 per cent class, or there¬ 
abouts. In other words, it would appear that while the dried blood is 
better suited to the foreign soils if a few soils are eliminated from con¬ 
sideration, cottonseed meal is better suited to the average soil, provided 
the influence of the amount of fertilizer used is disregarded. In general, 
it would appear that dried blood is a more readily and more efficiently 
nitrifiable material for the soils of the humid region than cottonseed meal. 
In a general survey of the results obtained with the foreign soils, it 
seems to be true beyond question that with respect to relative quantities 
of nitrates produced from the different forms of nitrogen, the soil nitro¬ 
gen is the most efficiently nitrified of the four forms tried. Sulphate of 
ammonia is the least efficiently nitrified, while dried blood and cotton¬ 
seed meal differ very little. Table II summarizes the situation with 
respect to one degree of nitrate formation only. 
