50 



BOARD OF AGRICULTURE. 



[Jan. 



Johnson,* in 1871, said that a German investigator found 

 that when a small amount of plaster, common salf, sulphate 

 of soda or nitrate of soda, was incorporated with the soil, 

 the quantity of water evaporated by the plant was re- 

 duced, in some cases, more than fifty per cent ; and when a 

 free alkali, like potash, was added, the quantity was also 

 very strikingly diminished. In 1850, Sir J. B. Lawes'f 

 trials showed a striking difference in the amount evaporated 

 by certain plants on mineral manure, mineral and am- 

 moniacal manure, and on unmanured soil, as follows : — 



KIND OF PLAirr. 



Total Watbb qivbn off bt 



Unmanured 

 Plants. 



Plants on Min- 

 eral Manure. 



Plants on 

 Mineral and 

 Ammoniacal 



Manure. 



Wheat, 3 plants. 

 Barley, 3 plants, 

 Clover, 1 plant, 



Grains. 



113,527 



120,025 

 55,093 



Grains. 



98,006 

 128,354 

 53,723 



Grains. 



55,996 

 85,124 

 13,671 



These figures correspond with the German results as 

 stated by Professor Johnson. But Sir J. B. Lawes,| at a 

 later date, shows certain modifications produced by fertilizer 

 upon the water relation of the soil. On the plots where 

 nitrate of soda was employed continuously year after year, 

 the soil apparently retained very much more moisture, and 

 presented other interesting physical characteristics, differing 

 from those obtained on adjoining land. In some experi- 

 ments by Professor Roberts, § at Cornell University, a mix- 

 ture of salt and plaster was added to some soil in pots on 

 July 11, and on August 16 the moisture in the soil was 

 determined in the laboratory, with the result of finding in- 

 creased water content in the soils to which salt and plaster 

 had been applied. Other illustrative facts might be noted, 

 and I think the observant person can readily adduce in- 



• Ag. of Conn., 1871, p. 240. 



t Hort. Trans., 1850, 45. 



t Jour. R. A. S., 1871, p. 104; 1873, p. 370. 



§ Proc. of the Soc. for the Prom, of Agr. Science, 1888, p. 60. 



