418 EXPERIMENT STATION RECORD. 



other properties of products obtaiued by extracting limed and unlimed compost 

 with water, precipitating with alcohol, and dialyzing the products are reported. 



The concentration of phosphoric acid in the soil in the neighborhood of 

 old centers of population, F. Hughes and A. Alad.jem (Agr. Jour. Egyiit, 1 

 {1912), No. 2, pp. 81-83). — ^Analyses of soil samples from the "Kom" of 

 Sakha showed a much higher phosphoric acid content than the soils of the 

 Delta of Egj'pt as a whole. It is stated that this " Kom " marks the site of one 

 of the oldest cities of the Delta, and that the accumulation of phosphoric acid is a 

 " clear case of valuable plant food being drawn from a large area and becoming 

 concentrated in the course of time over an area much smaller and more circum- 

 scribed." 



The quantities of radium and thorium, emanations contained in the air 

 of certain soils, J. Satteely {Proc. Cambridge Phil. Soc, 16 (1912), No. 6, 

 pp. ')l.'/-533, figs. 5). — Measurements of radium and thorium emanations in the 

 air of different soils to depths of 106 and 152 cm. showed at depths of from 

 100 to 150 cm. in gravelly soil about 2,000 times as much as there is usually in 

 the atmospheric air. 



The production and movement of nitric nitrogen in soils, R. Stewart and 

 J. E. Greaves {Cetitbl. Bakt. [etc.], 2. AM., 3Jt (1912), No. Jf-l, pp. 115-147, 

 flg. 1). — This article embodies the results of investigations previously reported 

 in Bulletins 106 and 114 of the Utah Station (E. S. R., 22, p. 617; 26, p. 616), 

 as well as of later investigations by improved methods on a new series of plats 

 on the same soil. These investigations dealt with the amount and distribution 

 of nitric nitrogen in the soil to a depth of 10 ft. as affected more particularly 

 by water conditions and crop. 



The results obtained indicated a pronounced variation in nitric nitrogen con- 

 tent of the soil from foot to foot during the season due to movement by water, 

 variation in nitrification, feeding of the plant, and fixation of nitric nitrogen 

 in the form of insoluble protein by micro-organisms. The application of irriga- 

 tion water had a distinct beneficial effect upon the formation of nitric nitrogen, 

 being greatest where 15 in. of water was applied. 



In cropped land there was always less nitrogen in the soil during the fall 

 than in the spring. In fallow soil, on the other hand, more nitro.gen was found 

 in the fall than in the spring, but this surplus largely disappeared during the 

 winter months. 



The amount of nitric nitrogen in alfalfa and oat soils was low. In corn and 

 potato soils it was high. Alfalfa was found to be a heavier feeder on soil 

 nitrogen than potatoes notwithstanding the fact that the alfalfa was abun- 

 dantly supplied with root tubercles. The concentration of the soil solution 

 was very low in alfalfa and oat soils and high in fallow, potato, and corn 

 soils. The concentration of the solution was always higher in fallow soil than 

 in alfalfa, oat, and corn soil, and nearly always greater in unirrigated than in 

 irrigated soil. It varied, however, quite widely not only with the crop grown 

 and the amount of water applied but also at different depths in the soil. There 

 was always a larger amount of nitric nitrogen in the fallow plats than in the 

 cropped plats, but when the amount of nitrogen removed in the crop was taken 

 into account it was found that more nitric nitrogen had always been formed 

 in the cropped soil. The amount of nitric nitrogen was found to be more con- 

 stant in the uncropped plats than in the cropped plats. The proportion of nitric 

 nitrogen was found to be comparatively constant in the lower foot sections of 

 the soil irrespective of the amount of water applied, up to 25 in., indicating 

 that there was little leachiug of the nitric nitrogen beyond the iower depths of 

 sampling. 



