SOILS FERTILIZERS. 131 



silicates (mica) are capable of giving in the course of the growing period con- 

 siderable quantities of potash to the plants. 



Laboratory studies were made of the exchange of bases in soils and silicates 

 in such cases. For this purpose soils of various types were used and also indi- 

 vidual silicates (mostly potash silicate). Of the displaced bases, calcium, potas- 

 sium, and ammonium were determined. Ammonium nitrate served as the dis- 

 placing solution for calcium, potassium chlorid for ammonium, and ammonium 

 chlorid, barium chlorid, and preferably, ammonium nitrite, for potash. 



On the basis of absorbed lime the richest soil was found to be a chernozem, 

 a poorer a forest clay, and still poorer a podzol. Chernozem also proved richest 

 in displaced ammonium. In the determination of displaced potash muscovite 

 gave higher values than orthoclase and sanidiue (this being in agreement with 

 the pot experiments). Ammonium chlorid displaced more potassium than did 

 barium chlorid. For the displacement of potash, however, ammonium nitrite 

 is most suitable since it gives close duplicates and allows rapid work (being 

 readily removed by mere heating of the aqueous solution). 



The exchange of bases in the salts of the so-called " weak " acids of the 

 soil, P. Eheenberg {Landiv. Jahrl)., 38 (1909), pp. 857-861; ahs. in Chem. Ats., 

 Jf (1910), No. 11, p. 1521). — The author concludes from his investigations that 

 the absorption of weak acids, such as carbonic acid and phosphoric acid, by 

 clay and clay soils is not due to colloidal but to chemical action. The strong 

 acids, such as bromic, nitric, and chromic acids, form relatively soluble calcium 

 salts, while the weak acids form rather insoluble salts and are thus apparently 

 absorbed by the soil. 



Availability of soil nitrogen in relation to the basicity of the soil and to 

 the growth of legumes, T. L, Lyon and J. A. Bizzell (Jour. Indus, and Engin. 

 Chem., 2 (1910), No. 7, pp. 313-315; ahs. in Jour. Soc. Chem. Indus., 29 (1910), 

 No. 15, p. 967). — In a series of comparative experiments results were obtained 

 which confirmed the commonly accepted view that a certain degree of basicity 

 in the soil is favorable to nitrification, and indicate that the addition of lime to 

 a soil deficient in this constituent produces a substantial increase in the nitrates 

 for at least four years after application. The growth of alfalfa and possibly 

 other leguminous plants on a soil well supplied with lime further promotes 

 nitrification. Timothy grown with alfalfa contained a higher percentage of 

 nitrogen than when grown alone, the increase being more marked when the soil 

 was well limed. 



Organic phosphorus compounds of the soil, J. Korolev (Isv. Moskov. Selsk. 

 Khoz. Inst. (Ann. Inst. Agron. Moscou), 16 (1910), No. 2, pp. i-98).— The 

 author gives a review of investigations on this subject from 1831 to the present 

 time, and reports the results of his own investigations, from which he draws 

 the following conclusions : 



No appreciable amount of phosphorus of the chernozem soil of Ufa belongs to 

 the mineral phosphates. Lecithin or a similar compound is not found in this 

 soil. A small portion of the organic phosphorus compounds is soluble in 12 per 

 cent hydrochloric acid. The acid solubility of the organic phosphorus of this 

 soil increases on heating the soil with water, resulting in phosphorus com- 

 pounds slightly soluble in water and easily soluble in acids. The solubility of 

 organic phosphorus compounds is greater in ammonia than in water after 

 the soil has been treated with hydrochloric acid. The organic phosphorus 

 of the ammoniacal solution is not fully precipitated with hydrochloric acid, a 

 portion of the phosphorus remaining in the solution. This partial hydrochloric- 

 acid solubility of the phosphorus of the ammoniacal solution is apparently due 

 to the action of the ammonia on the organic phosphorus compounds of the soil 



