CHAPTER VII. 
GYPSUM AS A FERTILIZER. 
Use Among Ancient People. 
In Germany and other parts of the old country, and in New 
York, Michigan, Ohio, and Virginia in this country, gypsum 
ground and uncalcined has long been used as a fertilizer. For 
this purpose it is sold under the name of iand plaster. Its ac- 
tion on the soils has long been a disputed question and various 
theories have been advanced to explain the effects, many of 
which have been pure speculation. 
Authentic examples in very considerable number are cited to 
prove that gypsum forms a good fertilizer on certain soils for 
certain crops. Other examples are cited where the plaster ap- 
parently had no effect whatever. As a result, many with the 
favorable experience have contended that gypsum is a univer- 
sal fertilizer endowed with the most wonderful and mysterious 
life-giving power; while others with their failures under a dif- 
ferent set of conditions, contend with equal persistence that 
gypsum possesses no value as a fertilizer under any conditions. 
Both sides base their opinions on practical experience and so 
are not to be moved in favor of their opponents. This explains 
why we find diametrically opposite statements in books sup- 
posed to be standard reference books on the subject of manures 
and fertilizers. 
The use of gypsum as a fertilizer is very old, probably older 
than the making of plaster of Paris. Virgil writes of the value 
of impure gypsum on cultivated lands, and it was used by the 
early farmers of Britain and Lombardy. 
The use of gypsum or land plaster as a fertilizer was recorded 
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