FERTILIZERS IN THE WEST 11 



requires them will not only increase the yield of dry matter 

 but will make it possible for plants to produce dry matter at 

 a lower water cost than on similar soils which have not 

 received such artificial stimulus. This is a vital matter in the 

 agriculture of a region where water is an essential considera- 

 tion." Even on clay soils "the addition of fertilizers increased 

 the yield in every case. With the complete fertilizer the in- 

 crease was over six times the yield on the unfertilized pot. 

 The total number of pounds of water required to produce one 

 pound of dry matter was likewise in every case very much 

 smaller on the fertilized than on the unfertilized pots." 



Practical experience has shown the conclusion of Dr. 

 Widtsoe to hold true under field conditions. Dr. K. W. 

 Thatcher, director of the Washington State Experiment 

 Station, states the following: 



"So far as can be determined by chemical analysis the 

 typical basaltic loam soils of Southeastern Washington, the 

 so-called 'volcanic ash' soils, contain ample supplies of the 

 most essential forms of plant food for large cereal and forage 

 crops for many years to come. It has been demonstrated, 

 however, that where the moisture supply is limited, as it is 

 throughout the non-irrigated districts of Eastern Washington, 

 crops can frequently make much better use of the soil moisture 

 if increased supplies of available plant food are furnished to 

 them. For this reason, it is sometimes profitable to use fer- 

 tilizers even if the soil does contain a large supply of total 

 plant food/' 



Dr. Thatcher then advises the farmers to make practical 

 field experiments with fertilizers and to find out for them- 

 selves. 



