AMERICAN INSTITUTE. 357 



two liundre(3 pounds to the acre, and produced a luxuriant and remune- 

 rating crop. 



If we sow 100 pounds of gypsum on our land, and it comes in contact 

 with a sufficient amount of ammonia, it will fix sulphate with 22 pounds of 

 ammonia, containing 17 pounds of nitrogen. I top-dressed an acre of 

 clover with 320 pounds of gypsum, and the excess produced over a con- 

 tiguous acre was fully equal to forty per cent. And the effect, so far from 

 passing away with the crop, extended its beneficial action for four years ; 

 showing that it exercises some influence over vegetation that is not alto- 

 gether understood. On the acre in question, the increased production, 

 the first year, was as above stated, 40 per cent. The second year 30 per 

 cent ; the third year 20 per cent, and the fourth year 10 per cent, 

 when the adjoining piece was nearly run out. 



In this experiment may be found the explanation why plaster has become 

 unpopular with agriculturalists, and its beneficial action deprecated. Find- 

 ing wonderful results produced by its use the first year, they used a double 

 quantity the next, which caused their land to become plaster sick, and 

 incapable of yielding remunerating crops. One thousand pounds of dry 

 hay, if analyzed, would not contain more than three pounds of sulphuric 

 acid. 



1,000 pounds of red clover, 4 pounds. 

 1,000 do of white do 3^ do 

 1,000 do of lucern, 4| do 



You will sometimes find a soil of uniform depth, where the surface, in 

 composition, is similar to the sub-soil ; when this is the case, it may bo 

 considered nearly inexhaustible for some plants, such as carrots, parsnips, 

 hemp, &c. But not for the clovers and leguminous plants until gypsum is 

 applied, when they will grow in unsurpassed luxuriance. 



Still, by the application of gypsum to such a soil, I once rendered it 

 completely barren, analyzed it, and discovered that it contained oxide of 

 iron, with which the sulphuric acid combined and formed green vitriol, or 

 sulphate, or iron, which poisoned the roots of all the plants coming in con- 

 tact with it. 



It is indispensable that a fertile soil should contain every substance that 

 the plant, we intend to grow in it, obtains only from the earth, in sufficient 

 quantities to supply all its requirements, while, at the same time, it must 

 be devoid of all poisonous matters. The effects of gypsum in Prussia, a 

 few countries in England, and many portions of the United States, is truly 

 amazing, while in other portions the benefit has never repaid the expense 

 of applying it. Lampadius remarks, that it may with certainty be stated, 

 that by the use of gypsum, the produce of clover and the consequent 

 amount of live stock have been increased, at least one-third,, in Germany. 



It is beyond contradiction, that the use of gypsum produces a largely 

 increased growth of clover and grass on certain soils, which, must be deter- 

 termined by experiment, that should be made on every farm. As far as- 

 research has gone, its action appears to be altogether chemical. The 



