10 
H. C. Expeeiment Station 
Discussion 
It would seem from the analyses in the foregoing table that liming 
has caused a loss of nitrogen from these soils, the extent of loss being 
relative to the amounts of lime applied. An alternate hypothesis, that 
the variations in nitrogen content are caused by differences in the rate 
of decomposition of the non-nitrogenous organic components of the 
muck is, however, not impossible. 
The- unlimed soils are considerably lower in total nitrogen content 
than are the soils receiving the lighter applications of lime. This 
may be indirectly the result of the failure of the untreated soils to pro¬ 
duce a crop during the last three years of the test. 
Liming has decreased the acidity of this soil. 
Failure of the original samples to show any consistent differences 
in their content of nitrate nitrogen suggested that temperature at the 
time of sampling rather than reaction was the factor limiting nitrifi¬ 
cation. Portions of each undried sample were, therefore, made up to 
uniform moisture content, placed into wide-mouthed bottles, and 
plugged with cotton. After incubation at room temperature and con¬ 
stant moisture content for four months, nitrate nitrogen and acidity 
were again determined with the result shown also in Table III. 
In the incubated soils two facts are clearly demonstrated; (1) that 
the extent of nitrification, as indicated by the concentration of nitrate 
nitrogen, is governed by the reaction of the soil, and (2) that incubation 
increases the acidity. It is probable that this increase in acidity is 
due to the production of nitric acid by nitrification. 
It was evident from inspection of the corn stalks that the presence 
of soluble compounds of iron contributes to the trouble experienced 
on this soil, formally, liming should remedy this condition. Ex¬ 
perience has shown, however, that liming at rates up to three tons per 
acre has not reproduced the original high yields nor has the applica¬ 
tion of four tons of lime bettered the yield obtained with three tons. 
On soils limed sufficiently to produce the maximum crop possible 
with lime alone, it was found that iron was deposited in the nodes of 
the corn stalks. It may be, therefore, that the soil at a reaction of 
pH 5.82, which was the lowest acidity found in the soil of any plat, 
is sufficiently acid to permit the presence of some soluble compound of 
iron. 
Carr and Brewer (2) have recently published data bearing on this 
point. They state that aluminum is almost completely precipitated 
as the hydroxide at pH 5.5, ferric iron is precipitated at about the same 
point while ferrous iron is completely precipitated at about pH 7.9. 
Apparently only one of the soils from the lime plats of the Branch Farm 
has been sufficiently limed to precipitate all of the soluble ferric and 
aluminum salts. 
