122 



EXPERIMENT STATION RECORD. 



"(1) A (lelicioncy <>f available potash greatly depressed the growth «i the i)laiit 

 even in the presence of an abundant supply of soda salts. A lack of soda in the 

 presence of potash sufficient for the plant's needs seemed to have no deleterious 

 effect whatever upon growth. 



"(2) Plants to which the necessary supply of potash was not accessible took up 

 more soda than when potash was present in abundance. Soda may be substituted 

 for potash in (juantity when the latter is lacking. 



" (3) While the substitution may take place in (luantity, it evidently can n(jt do 

 so in function, as is shown by the limited growth when the plants were dei)rived of 

 potash, even though soda was appropriated in increased proportions. 



"(4) The experiments incidentally suggest the view that the real need of plants 

 for certain essential mineral constituents is not even approximately measured l)y the 

 proportions of these constituents which the plant takes up." 



Can plants use soda in place of potash? F. H. Hall, W. H. Jokijan, and 

 C. G. Jentkk {Neip Turk State Sta. Bid. 193, popular ed., pp. 10, figs. ^).— This is a 

 popular sunuiiary of the above bulletin. 



The relative values of some nitrogenous fertilizers, W. A. Withkks and 

 G. 8. FH.\Pi^-{ North Carolina Sta. Bui. 170, pj>. lo-,i2). — The bulletin calls attention 

 to the results obtained by Miintz and Girard, and Boname (E. S. R., 9, j). 732) in 

 studies of the rate of nitrification of fertilizers, and also to the work of Jenkins and 

 Britton on the availability of nitrogenous fertilizers (E. S. E.., 10, p. 232), and reports 

 experiments on the relative rate of nitrification carried out as follows: 



"A sandy clay soil from a pasture was sifted through a coarse sieve (6 meshes to 

 the inch), and a quantity of material equivalent to 0.6 gm. nitrogen was intimately 

 mixed with 1,000 gm. of the soil. The soil was then placed in precipitating jars and 

 kept in a dark closet, enough water being added to raise the percentage from 6.3 to 

 11.6. At suitable periods 3 of the jars were weighed, and the estimated loss of 

 water was replaced in all the jars. The tenqjcrature was 28 to 30° C, and the time 

 was 3 weeks. When calcium carbonate was added, the amount was exactly sutiicient 

 to combine with the nitrogen of the fertilizer if the entire amount were converted to 

 nitric acid. At the end of the experiment the nitrates were leached out and the 

 amount determined by the Tiemann-Schulze method. The amount of nitrates found 

 in a blank experiment was deducted from the total." 



The results of these experiments, as well as of tests of the solubility in pei)sin- 

 hydrochloric acid and neutral permanganate, and of vegetation tests with oats and 

 Hungarian grass made by Jenkins and Britton, are given in the following table. 



Rate of nitrification and, araiUdAlitij of rariotis nitrogenous fertilizers. 



