191T] SOILS FERTILIZEB8. 719 



soila The soils of the cooler climate seemed to contain a greater number of 

 Mucorales and Peuieillixun, while those of the warmer climate were more 

 abundant in Aspergillus. The acid and water-logged soils were richer in num- 

 bers and species of Trichoderma than normal agricultural soils. 



Biological variations in soil plats as shown by different methods of 

 sampling, F. E. Aixjson and D. A. Coleman {Soil Sd., 3 (1917), No. 6, pp. 

 Jf99-505, figs. 2). — Experiments conducted at Rutgers College to determine the 

 influence of method of sampling soils on biological variations are reported. 

 Two one-twentieth acre plats, one of heavy clay growing timothy sod and the 

 other of sandy loam growing corn, were used. Samples were taken by the 

 Brown method (E. S. R., 28, p. 120) and by the Lipman sampling tube (E. S. R., 

 14, p. 556). 



The data obtained led to the belief that " where plats are uniform in char- 

 acter the biological variations of the soil at different points in the plat are net 

 great, or else we are not able to detect these differences by the present methods. 

 The tube method is superior to Brown's method both for ease of taking the 

 sample and from the standpoint of destruction of the plat, especially in an un- 

 cultivated area." 



The effect of sterilization of soils by heat and antiseptics upon the con- 

 centration of the soil solution, G. P. Koch (Soil Sci., S (WIT), No. 6, pp. 

 525-530). — Experiments conducted at Rutgers College to determine the influence 

 on the concentration of the soil solution of commercial sterilization as practiced 

 in greenhouses, sterilization as used in biological laboratories, and of the 

 presence of organic matter during the process of sterilization are reported. The 

 following conclusions were drawn : 



" The lowering of the freezing-point method is a satisfactory means of de- 

 termining soil solution concentration as influenced by sterilization. In com- 

 merical as well as laboratory methods of steaming soils, the heavier soils are 

 more influenced by sterilization than lighter soils. Steaming alone was more 

 effective in increasing the concentration than . . . the formalin treatments. 



"Applying formalin (1:50) and then steaming at 10 lbs, pressure increased 

 the concentration more than any other method tried. By this method the con- 

 centration was increased to three times the original concentration of the sou 

 solution. A considerable amount of soluble material is leached out of the soil, 

 and thus the concentration is lowered if the quantity of antiseptic solution ap- 

 plied is so great that the soil can not hold it against the force of gravity. . . . 



" Sassafras loam and . . . Penn loam soils were affected in the laboratory 

 sterilization method so that the concentration was increased 0.24 and 0.3 atmos- 

 phere, respectively. The concentration of . . . Norfolk sand containing a very 

 small amount of organic matter was not affected so that it could be detected by 

 the method employed. One per cent of dried blood increased the concentration 

 of the soil solution of . . . Norfolk sand 0.09 atmosphere, while 2 per cent cotton- 

 seed meal increased the concentration three times this amount." 



Some effects of organic growth-promoting substances (auximones) on 

 the growth of Lemna minor in mineral culture solutions, W. B. Bottomley 

 {Proc. Roy. Sac. [London}, Ser. B, 89 {1911), No. B 621, pp. 481-507, pis. 2, figs. 

 7). — Experiments on the influence of extracts of bacterized peat on the growth 

 of L. minor plants in mineral culture solutions showed that " the addition 

 to the mineral culture solution of 368 parts per million of organic matter from 

 the water extract of bacterized peat resulted, after six weeks, in a multiplica- 

 tion of the number to 20 times, and an increase in weight to 62 times, that of 

 the control plants. The water extract free from humic acid, representing an 

 addition of 97 parts of organic matter per million, gave 9* times the number 

 aad 29 times the weight ; 32 parts per million from the alcoholic extract 



