SOILS — FERTILIZERS. 127 



pyrogallic acid on the injurious iutlueuce of the organic corupounds, are re- 

 ported. 



It was found that " impure diliydroxystearic acid lias little injurious effect 

 upon corn or sorghum grown in pot experiments when applied before planting 

 at the I'ate of 500 parts per million of soil. . . . Vanillin and quinone applied 

 to the soil before planting at the rate of 100 parts per million of soil injured 

 the growth of only one of eight crops. . . . Sis successive additions of cumarin, 

 vanillin, or quinone at the rate of 100 parts per milliDn did not kill the plants." 



A comparison of these results with those of water culture experiments by 

 others showed that vanillin, cumarin, and quinone are much less injurious in 

 soil than in water cultures. This led to the conclusion that the results of soil 

 and water culture experiments may differ widely. It was further found that 

 vanillin and cumarin were oxidized in the soil, a considerable portion disap- 

 pearing in two weeks and only a little remaining until the end of the experi- 

 ments. 



Little evidence was obtained to show that fertilizers overcome the injurious 

 action of cumarin, vanillin, or quinone. " Pyrogallic acid and carbon black 

 showed no beneficial action in pot experiments, while acid phosphate or other 

 fertilizer was decidedly beneficial to the soils and produced decided increases. 

 The conclusion is that these poor soils need the plant food supplied by the fer- 

 tilizers and that the action of the fertilizer is to supply plant food and not to 

 overcome toxic substances." 



The formation of carbon dioxid and nitrates in the presence of large 

 amounts of carbohydrates, J. G. Lipman, A. AV. Blair, H. O. McLean, and 

 L. K. WiLKiNs {New Jersey Stas. Rpt. 1914, PP- 220, 221). — Laboratory ex- 

 periments with an acid loam soil to which dextrose was added at the rate of 3 

 gm. per 100 gm. of soil showed that nearly ten times as much carbon dioxid 

 was evolved from the portions of soil receiving dextrose as from those receiving 

 none. On the other hand, there was approximately 122 times as much nitrate 

 in the nondextrose portions as in the dextrose portions. 



Bacteriology of the general fertilizer plats, G. C. Given and L. G. Willis 

 (Pennsylvania Sta. Rpt. 1912, pp. 441-^54, figs. 5). — Studies on the bacterial 

 numbers and on ammonification in several plats of clay loam soil, which had 

 undergone varying cultural and fertility treatment for 30 years, are reported. 



A slight relationship was found between moisture content of the soil and 

 number of soil bacteria growing on nutrient agar. Temperature was more of a 

 limiting factor on bacterial numbers than moisture content, one of the lowest 

 counts being obtained from very cold, but not frozen, soil. Fairly high counts 

 were, however, obtained from frozen soil. Little or no relation was established 

 between bacterial numbers and the size of wheat crop. 



In ammonification experiments with cotton-seed meal ,it was found that 

 ammonification was very similar in rate and amount in soils receiving widely 

 varying treatment. 



A list of references to literature bearing on the subject is appended. 



Bacteriology of the general fertilizer plats. — III, Ammonifications, G. C. 

 Given (Pennsylvania Sta. Rpt. 1913, pp. 200-206, pis. 7). — In continuation of the 

 above experiments studies of ammonification and nitrification are I'eported. 



Further ammonification experiments, using cotton-seed meal and dried blood, 

 to determine the effects of the soils from the different plats upon the activity of 

 ammonifying organisms derived from a highly productive soil showed in all 

 cases a steady increase in ammonia production up to the seventh day. 



Nitrification experiments with these soils using ammonium sulphate showed 

 that " the same soils which apparently had no influence upon the vigor of the 



