u- 



SOILS FERTILIZERS. 23 



On osmosis in soils: The efficiency of the soil constituents as semiperme- 

 able membranes, C. J. Lynde and H. A. Dupr6 {Jour. Avier. Soc. Agron., 5 

 (.1913), No. 2, pp. 102-106, figs. 2). — In continuation of previous investigations 

 (E. S. R., 29, p. 124) experiments made with medium sand, fine sand, very fine 

 sand, silt, clay, and fine clay for the purpose of comparing the efficiencies of 

 these soil constituents as semipermeable membranes showed that for the solu- 

 tion used (clay subsoil solution) the sands did not act as semipermeable mem- 

 brane, but that the silt, clay, and fine clay did so act. The conclusion is drawn 

 that the finer the soil grains in a soil constituent the greater is the efficiency 

 of the soil constituent as a semipermeable membrane. 



The method and apparatus used are described. 



The action of hydroxyl ions on clay and clay soils in connection with 

 marling-, P. Rohland (Landw. Jahrh., 44 {191S), No. 3, pp. 437-440). — The 

 hydroxyl ions of calcium and other hydroxids act upon the clay of soil, form- 

 ing and flocculating colloid substances. This effect is greatest the first time 

 clays and clay soils are subjected to the action of the ions and diminishes 

 when the action is repeated until the clay particles lose the property of forming 

 colloids. This is said to explain the diminishing effect of repeated liming. 



The properties of so-called soil zeolites, E. Blanck (Fuhling\s Landw. Ztg., 

 62 (1913), No. 16, pp. 560-581). — The principal results of investigations bearing 

 on this subject are summarized, indicating the lack of exact information as to 

 the so-called zeolites of the soil. These are shown to be in no sense equivalent 

 to the mineral zeolite but may be more properly designated simply as adsorptive 

 gel mixtures of indefinite and variable mineralogical and chemical composition. 



Factors in the maintenance of permanent fertility of the soil, E. O. Fippin 

 (Jour. Amer. Soc. Agron., 5 (1913), No. 1, pp. 46-49, fig. i).— A diagram in the 

 form of a monument is presented which " is made up of the general practices 

 available for improving the soil put together according to their functional 

 relations and in the order of their range of influence." The foundation of 

 this diagram is the proper regulation of soil moisture, involving drainage and 

 irrigation. Lime in the form of free lime carbonate constitutes the second 

 course. Organic matter, chiefly in the form of humus, forms the third course. 

 Tillage in its various forms constitutes the fourth course, and plant food in the 

 form of fertilizers is placed last with the elements, phosphorus, sulphur, nitrogen, 

 and potassium, arranged in the order in which they are most likely to be needed. 



The agricultural utilization of acid lands by means of acid-tolerant crops, 

 F. V. CoviLLE {U. 8. Dept. Agr. Bui. 6, pp. 13). — The essential features of this 

 paper have already been noted from another source (E. S. R., p. 814). The 

 points emphasized as of special importance to agricultural investigators are 

 "(1) that soil acidity is not always an objectionable condition which invariably 

 requires an application of lime, (2) that under certain economic conditions a 

 complete system of acid-land agriculture is practicable and desirable, and 

 (3) that the extent to which our cheap eastern acid lands can be utilized with 

 small applications of lime, or under some conditions without its use. is a legiti- 

 mate and important subject for detailed investigation, from which may reason- 

 ably be expected results of far-reaching economic importance."' 



Formation of nitrates in soil after freezing and thawing-, T. L. Lyon and 

 J. A. BizzELL {Jour. Amer. Soc. Agron., 5 {1913), No. 1, pp. 45, 46). — Four pots 

 of soil, two containing Volusia silt loam and two Dunkirk clay loam soil on 

 which had been raised a crop of wheat and one of millet were used in these 

 experiments. One pot of each kind of soil was subjected to freezing and thaw- 

 ing and the other two were kept at a temperature above 50° F. 



The determination of nitrates in these soils after this treatment showed that 

 freezing had produced a condition of soil favorable for nitrate formation. This 

 25842°— No. 1—14 3 



