INSUFFICIENCY OF RAINFALL. 13 



The production of straw was very nearly double that of 

 grain in every case, and the increase constant and regular. 



In the very exhaustive experiments which have been 

 made by Mr. J. B. Lawes, of Kothamstead, England, to 

 ascertain the amount of water consumed by a growing 

 crop of wheat, it was very clearly shown, that for every 

 pound of dry matter produced, 200 pounds of water was 

 evaporated, and that for every pound of mineral matter 

 assimilated by the crop, 2,000 pounds of water passed 

 through the plant. Mr. Lawes therefore declared, that 

 for a maximum crop of wheat, in England, the supply 

 of rain water was totally inadequate. Leguminous plants, 

 (beans, clover, etc.,) required a still more abundant sup 

 ply of water than wheat, and of course the more luxuri 

 ant the growth, the greater the expenditure of water. 

 Comparing the results of Mr. Lawes investigations with 

 those at Montsouris, a striking equality is found. In the 

 maximum crop there grown, 727 Ibs. of water were evap 

 orated for one pound of grain and two of straw, giving 

 242 pounds of water for one pound of total produce. 

 If, as is probably the case, the weight of the roots was 

 included in Mr. Lawes estimate, as it was not in the 

 other, the approach to equality between the two results 

 would be very close indeed. One therefore corroborates 

 the other. 



These results show, in a very remarkable manner, the 

 absolute necessity for an adequate supply of water for the 

 successful prosecution of an advanced agriculture. The 

 plants grown in these experiments were supplied with 

 water at libitum. Those which grew luxuriantly under 

 the effect of the most active and valuable manure, viz. 

 a mixture of phosphate of ammonia, nitrate of potash, 

 and chloride of sodium a very complete fertilizer are 

 seen to have consumed a very large quantity of water, 

 and nearly five times as much as those which grew most 

 feebly. 



