SOILS FERTILIZEES. 819 



"Determinations of the rate of nitrification of soil from plats planted to 

 alfalfa and timothy, respectively, showed the alfalfa soil to nitrify more rapidly 

 than the timothy soil, both in the soil on which the crops had been grown con- 

 tinuously and in that from which they had been removed and on which the 

 soil had been kept bare for two seasons. The formation of nitrates was in the 

 same order when the soils were incubated with dried blood. . . . 



" Plats of land planted to certain crops in 1910 were kept bare of vegetation 

 during the early part of the growing season of 1911. Determinations of nitrates 

 in the soil of these plats showed a distinct and characteristic relation of the 

 several plants to the nitrate content of the soil in the year following that in 

 which the plants were grown. 



" Maize was the only crop following which the nitrates in the previously 

 planted soil were higher than in the unplanted soil. Potato soil was the next 

 highest in nitrates, and oat soil contained least nitrates. 



"Millet planted on these plats on July 1 was markedly influenced by the 

 • previous crops, but the luxuriance of growth was inversely proportional to the 

 nitrate content of the plats. . . . 



" Freezing and thawing produced a condition of soil favorable to nitrate 

 formation. . . . 



" Timothy maintained a lower nitrate content in the soil than did any other 

 crop. Mixed grasses — Phleum pratense, Agrostis alba, Poa pratensis — gave 

 much less nitrogen in the crop and the drainage water combined than was con- 

 tained in the drainage water from unplanted soil. . . . 



" Plants of two different kinds were grown, in combination and separately, in 

 soil and in ground quartz containing nutrient solutions. In a considerable 

 number of cases in which the plants were harvested at the blooming period 

 or before, one or both kinds made a larger growth in the combinations than in 

 the pure cultures, although there were at least twice as many plants growing 

 in the mixed as in the pure cultures. This increased growth of one plant in asso- 

 ciation with another was apparently not due to any increased supply of 

 nitrates, since the apparent stimulation of growth occurred with nutrient solu- 

 tion in which all the nitrogen was in the form of nitrates, as well as with 

 the soil." 



A bibliography is appended. 



Nitrogen fixation by organisms from Utah soils, E. G. Peterson and E. 

 MoHB {Science, n. ser., 38 {1913), No. 977, p. 416).— This is an abstract of a 

 paper presented before the Society of American Bacteriologists. 



" This paper is a preliminary note on a proposed extensive investigation re- 

 garding the fixation of nitrogen in Utah soils and the role played by micro- 

 organisms in this action, together with the various agencies influencing bacterial 

 action." Three forms were isolated. These are described and tests of their 

 nitrogen-fixing power are reported. The seasonal variation in fixation " was 

 found to be very marked from week to week without apparent regularity, a 

 marked increase in fixation power being noted from the middle of May to the 

 end of June." 



The ammonifying eflB.ciency and algal content of certain Colorado soils, 

 W. G. Sackett {Scioice, n. ser., 38 {1913), No. 977, p. 416).— The paper, read 

 before the Society of American Bacteriologists, of which this is an abstract, is 

 published in full in Bulletin 184 of the Colorado Experiment Station (E. S. R., 

 28, p. 31). 



Abnormal fixation of atmospheric nitrogen, C. T. Gimingham {Chem. 

 World, 2 {1913), No. S, p. 84)- — This is a brief critical review of the investiga- 

 tions by Headden and Sackett on the occurrence of excessive amounts of nitrates 

 In Colorado soils. 



