FERTILITY AND TRANSPIRATION 185 
yielded poor crops or crop failures — indicating 
thereby, since rainfall was the critical factor, that 
the fertility of the soil is important in determining 
whether or not with a small amount of water a good 
crop can be produced. Pagnoul, working in 1895 
with fescue grass, arrived at the same conclusion. 
On a poor clay soil it required 1109 pounds of water 
to produce one pound of dry matter, while on a rich 
calcareous soil only 574 pounds were required. Gard- 
ner of the United States Department of Agriculture, 
Bureau of Soils, working in 1908, on the manuring of 
soils, came to the conclusion that the more fertile the 
soil the less water is required to produce a pound of 
dry matter. He incidentally called attention to the 
fact that in countries of limited rainfall this might be 
a very important principle to apply in crop produc-. 
tion. Hopkins in his study of the soils of Illinois 
has repeatedly observed, in connection with certain 
soils, that where the land is kept fertile, injury from 
drouth is not common, implying thereby that fertile 
soils will produce dry matter at a lower water-cost. 
The most recent experiments on this subject, con- 
ducted by the Utah Station, confirm these conclu- 
sions. The experiments, which covered several years, 
were conducted in pots filled with different soils. 
On a soil, naturally fertile, 908 pounds of water were 
transpired for each pound of dry matter (corn) pro- 
duced; by adding to this soil an ordinary dressing of 
manure, this was reduced to 613 pounds, and by add- 
