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 t(j j^roduce 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 t(j apply in crop ]:)roduc- 

 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, im])lying 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 \yith different soils. 

 On a soil, naturally fertile, 908 jsounds of water were 

 transpired for each pound of dry matter (corn) i^ro- 

 duced ; by adding to this soil an ordinary dressing of 

 manure, this was reduced to G13 pounds, and by add- 



