EDITORIAL. 105 



of the physical and chemical forces operating in the plant. This 

 involved the determination of the factors of growth, dormancy, 

 transpiration, sap movement, tolerance of alkali and other com- 

 pounds, etc. Breeding experiments, and especially those relating 

 to the principles of breeding, have been a more recent development 

 and have resulted in encouraging progress. In these breeding 

 studies, however, as in all other lines of agricultural investigation, 

 every step in advance has shown the urgent need of greater preci- 

 sion of method and of attacking the problem from the fundamental 

 standpoint. 



Accordingly, the viewpoint of the investigator has constantly 

 shifted as he reached a new advanced point and looked at the field 

 from a fresh angle, and the doctrine to which he could conscientiously 

 subscribe has naturally undergone a constant revision. The outcome 

 of the plant-breeding investigations has been to furnish a much 

 clearer conception of the nature of plant evolution, heredity, and 

 improvement, and the limitations possible in turning these to advan- 

 tage. In other words, it has been placed upon a more practical 

 basis, and the exaggerated expectations for a time aroused have 

 been corrected and brought to a more reasonable ground. 



In the field of soil investigation the stations have made large con- 

 tributions. This work at first related principally to the chemical 

 and physical i^roperties of soils, but soon involved a study of soil 

 bacteria, ammonification, nitrification, denitrification, protozoa, 

 effect of heat, acidity, and alkalinity in relation to soil organisms 

 and to the plant. The moisture movement and the water relations 

 of soil, drainage, percolation, capillarity, flocculation, hygroscopic 

 moisture, the wilting point and water requirement of plants, and 

 related matters have formed a large chapter in soil investigation. 

 And the findings in these fields have been applied to the treatment 

 and handling of soils in such matters as liming, cultivation, mulch- 

 ing, plowing, subsoiling, fallowing, etc. 



In soil investigation, as in many other lines of work, the tendency 

 at first was to attempt to progi-ess too rapidly. It was assumed at 

 the outset by many that on the basis of a chemical analysis of the 

 soil a prescription could be written for the farmer, directing him 

 what to do in order to increase his crop yields. It was soon found, 

 however, that the question was a much more complicated one, and 

 the development of the present understanding of the soil, imperfect 

 as it is, is one of the large products of agricultural investigation. 

 Eecent work in soils has involved far more fundamental and more 

 narrowly restricted investigations of specific problems, classified in 

 the three general fields of chemistry, physics, and biology of soils. 

 Here, as elsewhere, it has been found necessary to understand the 

 nature of the problem before it could be successfully attacked. And 



