KDTTORIAL. 1105 



tions favoring the predominance of injnrioiis organisms which would 

 i-esult from hirger applications at any one time. 



It has thus been shown to be possible by the proper handling of 

 manure to promote the activily of the micro-organisms which (1) fix 

 atmospheric nitrogen, (2) transform nitrogenous organic matter into 

 more available compounds, and (3) act directly by the carbon dioxid 

 they ])roduce on the insoluble })hosphates and potash comjiounds of 

 the soil to render them available for the use of the higher plants, 

 without at the same time incurring any serious risk of loss by deni- 

 trificalion or other injurious i)rocesses. 



When we reflect that the above statements indicate only a few of 

 the many ways revealed by recent investigations in which soil fer- 

 tility is affected by bacteriological processes, we can readily believe 

 that further research in this most promising field will render neces- 

 sary a radical revision of many of the commonly accepted notions 

 of soil fertility and help to put -many features of present methods 

 of fertilizing and soil management on a more rational basis, 



Kecent discoveries in soil bacteriology give a peculiar significance 

 to Berthelot's dictum that the soil is a living thing {la terre est 

 quelque chose de vivant) and furnish one of the many evidences 

 of the keen insight of that eminent scientist. It was this keen 

 scientific discernment, says Lipman, " that largely contributed to a 

 better appreciation of soil bacteriological activities as a factor in 

 plant production. His experiments dealing in the main with specific 

 bacteriological processes, just as the work of Schloesing and Miintz, 

 AVarington, and Winogradski, of Deherain and Maquenne, of Gayon 

 and Dupetit, or of Hellriegel and Wilfarth dealt with specific 

 processes, furnished none the less a strong argument for a more sys- 

 tematic study of soil bacteria in general, and led gradually to the 

 recognition of bacteriological methods as a valuable aid in the study 

 of soil problems. Henceforth the soil chemist, soil physicist, and 

 soil bacteriologist, Avorking in harmony, must each do his share in the 

 solution of these problems." 



Development in the field of soil bacteriological investigations has 

 not been as rapid, nor has the subject received as wide attention, in 

 this country as abroad. This is true despite the widespread activity 

 in soil studies and fertilizing problems. This Department and a few 

 of the experiment stations have made important contributions to 

 this subject, particularly in the field of fixation of nitrogen by 

 micro-organisms in symbiosis with leguminous plants. The stud}^ 

 of soil bacteriology in its broader aspects, however, has been limited 

 to the Avork of a comparatively small number of investigators in this 

 country. These phases include the fixation of nitrogen, both sym- 

 biotic and nonsymbiotic, nitrification and other biological processes 



