SOILS FERTILIZERS. 



523 



F ^ 



desired depth (6 cm.)- A graduated (5 to 10 1.) flask F, with rubber stopper 

 and glass tube T 1 cm. in diameter is inverted with its neck in the steel tube, 

 as shown in the figure, and maintains a constant level of water 3 cm. above 

 the surface of the soil. The rate of percolation of water through the soil 

 is shown on the graduated scale of the flask. 



Investigations with humus, J. Hudig {Cultiira, 22 {1910), No. 267, pp. 530- 

 5/f8). — This article reviews previous investigations on the character of the 

 humus substances of the soil, and reports pot experiments with oats on sand to 

 which had been added varying amounts of humus (sodium hydroxid) extracts, 

 organic matter, artificial humus prepared by boiling sugar with hydrochloric 

 acid, and pyrogallol, with a basal fertilizer furnishing sufficient amounts of 

 phosphoric acid, potash, and nitrogen, and ground limestone or sodium carbon- 

 ate to correct acidity. 



Humus extract and organic matter combined produced sickness in the oat 

 plant. Increased amounts of sugar humus reduced the sickness of plants. 

 Pyrogallol soils showed no plant sickness during the first 

 three seasons, but during the fourth season those soils 

 which had received calcium carbonate or sodium carbonate 

 were affected. The author concludes that pyrogallol 

 leaves an insoluble substance in the soil which is changed 

 by culture and fertilizing and thus causes the plants to 

 become sick. 



On the influence of hum.us substances on the de- 

 composition of urea into ammonia, H. R. Christensen 

 (Tidsskr. Landhr. Plantcavl, 11 (1910), No. 1, pp. 19-109, 

 pi. 1). — In a study of the conditions of the decomposi- 

 tion of urea in the presence of humus substance a small 

 rod bacterium {TJrohaciUus beijerinckii n. sp.) was iso- 

 lated which can decompose urea into ammonium car- 

 bonate even in the absence of other organic substances. 

 This result is of interest biologically because the bacillus 

 is the only organism now known which can utilize urea 

 as a carbon nutrient. A description of the character- 

 istics of the bacillus is given, with reproductions of photo- 

 graphs, of agar and bouillon plate cultures. 



Pentosans in soils, E. C. Shoeey and E. O. Lathrop 

 (Jour. Amer. CJiem. Soc, 32 (1910), No. 12, pp. 1680- 

 1683). — The official method of determining pentosans, 

 based upon the amounts of furfural obtained on boiling with 

 hydrochloric acid, was applied to 10 soils, 10 gm. of soil being boiled with 12 per 

 cent hydrochloric acid until there was no further evolution of furfural. The 

 pentosan carbon in the soil as determined by this method varied from 1.3 to 28.53 

 per cent. The third lowest result, 1.83 per cent, was obtained from a soil con- 

 taining the largest quantity of organic matter. 



A further study of a soil type containing 2.75 per cent of pentosan indicated 

 that while a crude pentosan was probably present in this soil as a plant residue, 

 it can not be assumed that the formation of a pentose sugar, and from it fur- 

 fural, necessarily indicates the presence of a pentosan as such, since pentose 

 sugars are a part of the complex molecule of hucleoproteins and phosphatids 

 and are split off from these on heating with acids. 



Some acid constituents of soil humus, O. Schreiner and E. C. Shorey 

 (Jour. Amer. Chem. Soc, 32 (1910), No. 12, pp. i67i-i 680). —This article de- 

 87402°— No. 6—11 3 



Fig. 1. — Apparatus for 

 determining perme- 

 ability of soils in 

 place. 



