332- USE CF SULPHATE OF LIME OR GYPSUM. 



on many accounts to discover new outlets for the products of these impor- 

 tant manufactories, that were there only theoretical reasons for believing 

 them likely to benefit practical agriculture, it would be desirable to make 

 trial of their effects upon the land. But their favorable influence has 

 already been shown, and it remains, therefore, only to work out the de- 

 tails by which their application to this or that soil or crop shall be so 

 regulated as to yield a fair and constant profit to the farmer who em- 

 ploys them. 



1 have elsewhere (Appendix, p. 4,) recommended the application of 

 sulphatie of soda at the rate of 1 cwt. of the dry salt, or of 2 cwt. of crys- 

 tals (cost 10s. or lis.) per acre. The Epsom salts are only sold in crys- 

 tals, and l-i- cwt. (cost 12s.) in this form, should be nearly equal in efl[i- 

 cacy upon the land to 2 cwt. of crystallized sulphate of soda. In this 

 proportion, therefore, it would be proper to apply it to the young crops, 

 esj)ecially of wheat, clover, peas, beans, and other leguminous plants. 



5°. Sulphate of Lime {Gypsum) has been long and extensively applied 

 to the land in various countries and to various crops. In Germany its influ- 

 ence has been most generally beneficial upon grass and red clover, while 

 in many parts of the United States it is apphed with advantage to almost 

 every crop. In the former country and in England, it is usually dusted 

 over the young plants in early spring ; in America it is frequently sown 

 with the seed, or, in the case of potatoes, put into the drills or holes 

 along with the manure. The propriety of adopting the one rather than 

 the other of these methods will depend upon the nature of the soil and 

 upon the climate. Gypsum requires much water to dissolve it, and in 

 dry soils, climates or seasons, it might readily fail to influence the crop 

 at all, if applied in the form of a top-dressing only. 



It would appear that the time and mode of its application has more 

 influence upon its activity than we might suppose — siuce, according to 

 Professor Korte, when appli'ed to clover at different periods in thesyiring, 

 the produce of different parts of the same field was in the following 

 proportions : — 



Undressed, 1 00 lbs. 



Top-dressed on the 30th of March, 132 lbs. 



13th of April, 140 lbs. 



27th of April 156 lbs.* 



The effect of a top dressing of gypsum seems therefore to be greatest 

 when it is applied after the leaves have been pretty well developed. f 



Theory of the action of these sulphates. 



a. It does not seem diflflcult now to account for the general action of 

 these several sulphates of potash, soda, magnesia, and lime. The ex- 

 planation may be deduced partly from recent chemical analyses, and 

 partly from agricultural experiments more lately made by practical men. 



It has been found, for example, that Sulphur is a constant and appa- 

 rently necessary constituent of the glyten and albumen of the several 

 varieties of grain, and of the legumin, which forms the largest part 



t Mdglinscke Jahrbv-cher, I, p. 85, quoted in Hlubek's PJlanzenndhrung. 



I Cau the result here mentioned have any connection with the fact observed by Peschier. 

 that gypsum laid upou the leaves of plants is gradually, converted into carbonate, its sulphuric 

 acid being absorbed ? 



