SOILS FERTILIZERS. 317 



sectious is being reduced by the bodily reiuuvai of tlxe soil material. He particu- 

 larly draws atteutiou to the relative erosion of forested and cleared lands, and 

 to the relation of erosion to lumbering, mining, power development, navigation, 

 and agriculture. It is pointed out that the main factor in the better utilization 

 of rainfall, the reclamation of eroded soils, and the prevention of si'il erosion, 

 is the retention of water where it falls by means of ditferent soil treatments, 

 including terracing, deep plowing, foresting, increasing the humus supply, etc., 

 thus either increasing the porosity of the soil and its absorptive capacity for 

 rain water, or decreasing the velocity of the surface run-off and keeping it 

 within safe limits. 



Soil erosion and its remedy by terracing and tree planting, J. R. Smith 

 (Science, n. ser., 39 {1914), No. 1015, pp. 858-862). — The author in discussing 

 erosion of sloping soils, and factors aggravating or retarding thii>, draws atten- 

 tion to the possibilities offered by the so-called plowless utilization of land, not 

 only for checking erosion, but also for increasing the crop area. This plan 

 includes as main factors (1) forestry by means of crop trees to control erosion 

 and provide forage and food, and (2) moisture and fertility control by means 

 of careful terracing. 



The influence of winds in the formation of agricultural soils, A. Bencke 

 (Natuncissenchaften, 2 (191Ji), No. 16, pp. 396-398). — The author discusses 

 briefly wind erosion, transportation, and dei>osition of soil-forming materials, 

 relative to the formation and fertility of different types of agricultural soils. 



The environment of soil organisms, F. H. H. van Suchtelkn {Science, 

 n. ser., 39 (1914), No. 1012, p. 763). — In a study of soil as a culture medium a 

 method was devised for obtaining the soil solution based on its displacement by 

 inactive substances (paraffiu oil, vaseline, etc.). The concentration of the soil 

 solution thus obtained was similar to that of the very first portion of drainage 

 water obtained by careful percolation through a large quantity of soil. Physico- 

 chemical and chemical examinations of the liquid obtained by the displacement 

 process showed that different soils, soils closely adjacent, and soils of the dif- 

 ferent layers, contained soil solutions of different compositions. 



Antagonism between salts as affecting soil bacteria, C. B. Lipman {Science, 

 n. ser., 39 {1914), No. 1012, p. 764). — Experiments dealing with the antagonism 

 between anions of the alkali salts — sodium chlorid, sodium carbonate, and 

 sodium sulphate — showed that both as regards ammoniflcation and nitrification 

 it was possible to improve the soil as a medium after it had been made toxic 

 for the bacteria in question by means of any one of these salts, through the 

 addition of any other of the three. " Thus briefly, it was possible at times to 

 triple and quadruple the total salt content of the soil and still make it a better 

 medium for ammoniflcation and nitriflcation than it was with one-third or one- 

 fourth of the total salt content consisting, however, of but one salt." The 

 author indicates the great significance of this in regard to the management and 

 control of alkali land. 



Studies on ammoniflcation in soils by pure cultures, C. B. Lipman and P. S. 

 BUEGESS {Univ. Cal. Puhs. Agr. Sci., 1 {1914), No. 7, pp. 141-172). — Comparative 

 tests of the power of pure cultures of Bacillus mesentericus vulgatus, 

 Pseudomonas putida, B. vulgatns, B. megatherium, B. mycoides, B. suitilis, B. 

 tumescens, Sarcina lutea, B. proteus vulgaris, B. icteroides, B. ramosus, Strep- 

 tothrix sp., P. fluorescens, P. vulgaris (Novy strain), and Micrococcus tetragenus 

 to produce ammonia from dried blood, tankage, cotton-seed meal, sheep and 

 goat manure, peptone, fish guano, and bnt guano in sandy soil, clay loam, and 

 black clay adobe soil are reported and discussed and the results compared with 

 those obtained by other investigators. 



