162 
The presence of soluble aluminum instead of soluble iron is a condition 
similar to that found in the acid soil of the Wanatah experiment field in 
Laporte county (as reported by Abbott, Conner and Smalley in Bul. 170 
of the Ind. Exp. Station). 
There is little danger of soluble salts of iron being present in well-drained 
and aerated soils or in irrigation water which has been exposed to the air 
for any length of time. This is due to the fact that soluble salts of iron 
readily oxidize and are precipitated on exposure to air. Soluble salts of 
aluminum are not readily precipitated and there is danger of these being 
present in injurious amount in acid soils either drained or undrained and in 
mine waters. 
On the Wanatah field it was necessary to apply some form of lime to 
neutralize the acidity before crops could be grown. It was also found that 
aluminum nitrate was just as injurious to corn grown in water cultures as 
was an equivalent amount of nitric acid. It would undoubtedly be necessary 
to neutralize the acidity of the coal mine water with some form of lime before 
it could be utilized for irrigation purposes. 
