SOILS FERTILIZEKS. 515 



ments with seven different kinds of soil extending through two years are 

 reported. Water was applied at four different rates, namely, 30, 50, 70, and 90 

 per cent of the water capacity of the soils. 



It was observed that the ratio of grain to total yield decreased as the water 

 supply increased. The nitrogen content of the crop decreased, while the 

 potash, and especially the phosphoric acid, increased with increase of water 

 supply. 



A note on previous observations on the behavior of nitrate in cultivated 

 soil, VoGEL (Lanilw. Vers. Stat, 82 (1913), No. 1-2, pp. 159, 160; ais. in Jour. 

 Chem. Soc. [Lo7idon], 101, (1913), No. 609, I, pp. 810-811) .—Attention is called 

 to an error in some of the results previously reported (E. S. R., 28, p. 521) 

 which showed very high losses of nitrates. The very high results reported 

 were due in some cases to fixation of nitrates by the porcelain dishes used in 

 the laboratory determinations. There was observed, however, a loss of 10 to 12 

 per cent of nitrates by denitriflcation in 4 days when humus soils were exposed 

 to the air in thin layers. 



The condition of soil phosphoric acid insoluble in hydrochloric acid, W. H. 

 Fry (Jour. Indus, and Engin. Chem., 5 (1913), No. 8, pp. 664, 665). — From the 

 results of tests by others of the ofiicial method of extraction with hydrochloric 

 acid of 1.115 specific gravity the author concludes that "there may be a very 

 minute quantity of phosphoric acid in soils in hydrochloric-acid-insoluble com- 

 pounds, but a large part of the phosphoric acid not extracted is present in a 

 soluble form — that is, as apatite — which is protected from the action of the 

 acid." 



A study of bacteria at different depths in some typical Iowa soils, P. E. 

 Brown (Ccnthl. Balct. [etc.], 2. AM., 31 (1913), No. 11-21, pp. 491-521, pis. 

 9). — The substance of this article has already been given from another source 

 (E. S. R., 2S, p. 627). 



The prevalence of Bacillus radicicola in soil, K. F. Kellerman and L. T. 

 Leonard (Science, n. ser., 38 (WIS), No. 968, pp. 95-98). — This is a brief ac- 

 count of an unsuccessful attempt to utilize various synthetic media in deter- 

 mining the relative distribution and quantitative function of B. radicicola in 

 three different kinds of soil. 



The complexity of the micro-org'anic population of the soil, H. L. Bolxey 

 (Science, n. ser., 38 (1913), No. 961, pp. 48-50).— This article states that in 

 investigations to ascertain what it is that tends to limit grain production or to 

 cause deteriorated grain on fertile soils the author found " that if we bring 

 about rather perfect sterilization in potted soils, the limiting factor on grain 

 production is done away with, provided we do not reintroduce it by means of 

 internally infected seeds or other wheat disease-producing matters. Bacteria 

 and amoebfB do not seem to play any primary part in this problem of deteriorated 

 cereal crops." He was not able " to find any cereal crop-limiting factors of any 

 importance associated either with indefinite toxic substances or with the ac- 

 tivity of bacteria." He did find, however. " that there are at least one or more 

 species each of the following moldlike fungi which, when in the soil, are real 

 cereal crop-limiting factors: Fusarium. Alternaria, Helminthosporium, Colleto- 

 trichum, Macrosporium, and Ophiobolus. . . . Most of these organisms are 

 not only persistent in the soil, remaining there by way of the stubble and roots 

 of their host plants, but may be introduced with the seed, fresh or improperly 

 composted manures, etc., most of them being what may be spoken of as internal 

 seed-infecting organisms." 



The author emphasizes the necessity of using disease-free seedlings in investi- 

 gations on the bacterial and toxic phases of the question of soil fertility and 

 briefly reports the results of experiments with such seedlings grown in synthetic 



