EXPERIMENT STATION BULLETINS. 339 



unfavorable reactions with fertilizers and plant nutrients developed within 

 the soil mass; to dehver nutrients to plants under more favorable conditions; 

 and to provide a more congenial medium for the development of beneficial 

 bacteria. By considering the transformations of the chemical compounds 

 involved the applications of the foregoing statements will become apparent. 



Some of the transformations and effects of fertilizer salts when acldecl to 

 soils may be anticipated from the results presented herein especially when 

 the class of salt is known. Volumes may be written on this subject but 

 only a short discussion of principles will be given here. Some of the effects 

 of chemicals on soils are as follows: (1) An equivalent exchange may take 

 place between the cation of a neutral salt and a soil element thereby enriching 

 the soil solution with the resulting soluble compounds. (2) Any molecule 

 of a hydrolyzing salt may appear in the soil solution after treatments with 

 this class of salt. (3) Hydroxides may be partially or wholly fixed in the 

 soil depending upon the solution concentration. (4) Acid salts may act 

 similarly to acids and leave insoluble hydroxides in the soil. (5) The gen- 

 eral effect depends upon kind and quantity of reacting materials. There- 

 fore, from a chemical standpoint the proper fertilization of each soil is an 

 individual proposition and one that requires careful study if maximum bene- 

 fits are to be obtained. The same line of reasoning applies to all soil experi- 

 mental work where soils are treated with chemical compounds. In order to 

 explain the results obtained it is necessary to know the chemical changes 

 produced by the soil treatments. Much chemical experimental work has 

 been done on soil classes or soil types as a basis; but there is a considerable 

 variation in the chemical constitution of similar classes of soils, in fact, there 

 may be greater differences in this respect between soils of the same class than 

 between soils of different classes. In this investigation there is a marked 

 similarity in the results from the alkaline sandy loam and acid silt loam 

 soils and the alkaline medium sand and acid sandy loam soils; while the 

 results from similar classes vary considerably except in case of the clay loam 

 soils. It is evident that soil types or classes based on physical properties 

 provide no consistent basis for chemical investigations designed to study the 

 effects of chemical compovmds on biological growths or soil processes. 



A common criticism of field experimental work with fertilizers from a 

 scientific standpoint is that results obtained can not always be explained. 

 An apparent reason for this situation is that the effects produced on the 

 soils by the applied fertilizers are not known. Whatever may be said in 

 this connection, it is cextain that when soil investigators pay more attention 

 to the chemical nature of the soils under investigation the science and prac- 

 tice of soil management will be greatly benefited thereby. 



OONiDEINSED SUMMAiRY 



Data are presented in this publication showing the general effects of 

 applications of neutral salts, hydroxides and hydrolyzing salts to acid and 

 alkaline soils (litmus paper test) of several classes. The experimental pro- 

 cedure consisted in bringing together 100 gm. of air dried soil and 500 c.c. 

 of salt solution for a period of one hour, filtering through paper and analyzing 

 the resulting solution. Results are briefly summarized as follows: 



1. When solutions of neutral salts were placed in contact with the soils 

 used the cations of the salts were fixed in the soils and closely equivalent 

 quantities of calcium and magnesium or other elements previously fixed in 

 the soils by chemical treatments were found in the resulting solutions. 



