EFFECT OF PARAFFIN ON THE ACCUMULATION OF 

 AMMONIA AND NITRATES IN THE SOIL 



By P. L. Gainey, 

 Soil Bacteriologist, Kansas Agricultural Experiment Station 



INTRODUCTION 



For many years paraffin has found a wide use in the study of soil 

 biology, plant physiology, soil fertility, mycology, and kindred sub- 

 jects. Its peculiar physical properties, chemical inactivity, and com- 

 parative resistance to biological activity render it especially adapted 

 to a variety of uses in these sciences. In many instances it is capable 

 of rendering very valuable service. It is the purpose of this preliminary 

 report, however, to call attention to certain dangers attendant upon 

 such widespread use. 



Perhaps the widest use of paraffin in the studies previously mentioned 

 has been in the "paraffin wire-basket method" of studying soil fertility, 

 a method recommended by the Bureau of Soils, United States Depart- 

 ment of Agriculture (i) * and in a large number of variations from this 

 method where paraffin is used to accomplish the same end. The object 

 of its use in such instances has been in most cases to surround the medium 

 (soil or solution) with a substance of a very inactive nature, impervious 

 to both water and air. The principle of the above method as recom- 

 mended by the Bureau of Soils and later adapted to physiological as 

 well as fertility studies, consisted in substituting wire baskets coated 

 with paraffin for the metallic or earthenware containers more commonly 

 employed for such purposes. 



According to Whitney and Cameron (9, p. 38), 



this form of basket has been eminently satisfactory. 



Hoffmann (5) also has recommended the use of a paraffin block as a 

 means of supporting seedlings growing in cultural solutions. Various 

 modifications of this method have found use in a number of laboratories. 



The Michigan Experiment Station (2) has made rather extensive use 

 of paraffin oil in the separation of a soil solution to be used subsequently 

 in chemical and physiological investigations of soil-fertility problems. 

 Other instances are recorded in which the use of paraffin has been recom- 

 mended in biological and cultural studies. 



EXPERIMENTAL WORK 



In experimental work to ascertain whether aeration can take place 



sufficiently in an uncultivated soil to maintain aerobic conditions in the 



subsurface, it became necessary to use a substance of a physical nature 



similar to paraffin. The commercial Parowax, prepared for the trade by 



' Reference is made by number to " Literature cited," pp. 363-364. 



Journal of Agricultural Research, Vol. X, No. 7 



Washington, D. C. Aug. 13, 1917 



ji (355) Key No. Kans. — 9 



