1916] SOILS — FERTILIZERS. 817 



It was found that " only a part of the salt added to the soil in pot cultures 

 could later be recovered from it by water digestion. This apparent loss of 

 salt . . . was greater in the case of sodium carbonate and sodium sulphate than 

 with sodium chlorid. 



" Where sodium carbonate was added to a soil the absorption was greater 

 in fine soil, rich in organic matter, than in sand. The limit of tolerance of crop 

 plants to the salt in the soil is determined by the quantity of salt that can be 

 recovered from the soil rather than by the quantity added to the soil. The 

 carbonates and bicarbonates of sodium are mutually interchangeable in the 

 soil, and the toxicity of the soil solution appears to depend upon the quantity 

 of the basic radical held in the soil regardless of the form of the acid radical, 

 . . . The proportion of recoverable salt which would reduce by one-half the 

 growth of wheat seedlings was for the carbonates 0.04 per cent of the dry weight 

 of the soil, for the chlorids 0.16 per cent, and for the sulphates 0.35 per cent. 

 The proportion of recoverable salt which prevented germination of wheat was 

 for the carbonates 0.13 per cent, for the chlorids 0.52 per cent, and for the 

 sulphates 0.56 per cent." 



The toxic action of soluble aluminum salts upon the growth of the rice 

 plant, K. MiYAKE {Jour. Biol. Chem., 25 (1916), No. 1, pp. 23-28; abs. in Jour. 

 Sac. Chem. Indus., 35 (1916), No. 12, p. 700; Chem. Abs., 10 (1916), No. U, p. 

 1902). — Experiments conducted at the University of California are reported in 

 which rice seedlings were grown in solutions of aluminum chlorid and hydro- 

 chloric acid of concentrations varying from 1/1,000 normal to 1/20,000 normal. 



It was foxmd that aluminum chlorid was toxic to the growth of rice seedlings, 

 even in dilute solution, the toxic effect appearing in concentrations greater 

 than 1/7,500 normal. " The toxicity of aluminum chlorid seems to be approxi- 

 mately equal to that of hydrochloric acid of the same normality, [and] is not 

 due to the hydrogen ion formed by hydrolysis of the salt in solution. The con- 

 centration of hydrogen ions formed by the hydrolysis of aluminum chlorid is 

 less than that formed by dissociation of hydrochloric acid of the same nor- 

 mality. Since the chlorin ion is not toxic to the growth of rice seedlings in 

 such dilute solution, colloidal alvmiinura hydroxid or unhydrolyzed aluminum 

 chlorid molecules or aluminum ions may be the toxic factors. The toxicity of 

 soluble aluminum salts is dependent upon the amount of aluminum itself. 



" The determination of soil acidity by titration in which the soil extract is 

 titrated with standard alkali is a logical method of determining the amount 

 of bases which should be added to the soil for the amelioration of its infertility ; 

 because, although the titration does not indicate the true acidity of the soil, yet 

 it does afford a measure of the bases which must be added to neutralize the 

 free acid and decompose the aluminum salts, either or both of which may be 

 responsible for the infertility." 



The agricultural value of greensand marl, A. W. Blair (Netv Jersey Stas. 

 Circ. 61 (1916), pp. 2-13, fig. 1). — This circular includes a discussion of the 

 agricultural value of greensand marl, and reports analyses of 42 samples col- 

 lected in New Jersey showing that the phosphoric-acid content varied between 

 0.045 per cent and 2.31 per cent and the potash content between 1.03 per cent 

 and 6.5 per cent. 



The utilization of molasses as a manure, L. De Waai- (Internat. Sugar Jour., 

 18 (1916), No. 210, pp. 267-272). — Fertilizer experiments with molasses in heavy 

 clay and sandy cane soils are briefly reported. 



The results are taken to indicate that " molasses constitutes a valuable recti- 

 fier for cane soils, which, when applied in combination with organic matter, has 

 given marked results in estate experiments on a large scale during three con- 

 secutive years. Even in a diluted form the results were very encouraging. 



