40 BOARD OF AGRICULTURE. [Jan. 



various plants, under different circumstances of manurial 

 application, were as follows : — 



Each tiiiil. Grains. 



Wheat, 3 plants, 55,996 — 113,527 



Barley, 3 plants, 85,124—120,025 



Bean, 1 plant (Vicia f aba), . . 112,231—117,869 



Pea, 1 plant, 96,405—109,082 



Clover, 1 plant, .... 13,671—55,093 



At a later date, in 1871, he reports * as a summary of re- 

 sults attained, that " in the growing and ripening of either 

 graminaceous or leguminous corn crops, probably on the 

 average from 250 to 300 parts of water are given off for one 

 part of total dry substance, fixed or assimilated;" or, as 

 summarized later by a writer, f that for every ton of really 

 dry substance grown, a depth of three inches of rain would be 

 evaporated through the vegetation ; and this, let me remind, 

 is for England, with its moist climate and sunshine of little 

 intensity. Calculating from this data, we would have, in a 

 corn crop of 50 bushels, a total yield of about 4 to 5 tons of 

 plant, containing from 1,600 to 2,100 pounds of dry matter, 

 which, multiplied by 300, — for the maize plant is a great 

 evaporator of water, and the American climate is an intensely 

 evaporative one, — represents a loss, through exhalation, of 

 at least 240 to 315 tons of soil water per acre ; or, as an inch 

 of rainfall is equivalent to about 100 tons per acre, to an 

 equivalent of from two to three inches of rain. 



Returning now to our illustrative analysis, we find that of 

 water and the other constituents usually reckoned as para- 

 mount in importance, viz., nitrogen, phosphoric acid and 

 potash, our estimated crop of 50 bushels of corn, in its 

 growing, removes from the soil, approximately: — 



Water, 6,323 — 7904 lbs. 



Nitrogen, 26— 33 lbs. 



Phosphoric acid, .... 6-8 lbs. 



Potassa, 22—28 lbs. 



Let us now review the extent of evaporation from the soil. 

 In England, where, on account of the moist climate and rather 

 equable temperature, the yearly losses through evaporation 



* Jour. R. A. S., 1871, p. 93. 



t W. H. Wheeler. Jour. R. A. S., 1878, p. 15 



