COMMEUCIAL FEETILIZEBS 629 



entirely lost to the soil after the organic matter has been 

 destroyed by ignition. It is therefore not due to an 

 enzyme, as stated by Kdnig, Hasenbaumer, and Coppen- 

 rath/ who first investigated the subject, nor entirely to 

 organic substances in the soil. Doubtless there are several, 

 or perhaps many, activating substances any of which have 

 this property. It is altogether likely that other catalyzers 

 exist in soils, and that they affect various reactions that are 

 concerned in plant production. Among these substances, 

 as pointed out by Ivonig, Hasenbaumer, and Coppenrath,^ 

 are manganese and iron oxides, which are well knowm to 

 exert catalytic action on certain reactions. While soils 

 naturally possess certain catalvtic powers, it seems possible 

 to still further activate some soils by proper applications 

 of so-called catalytic fertilizers. 



Organic matter is doubtless concerned in the catalytic 

 properties of soils, and the investigators just mentioned 

 found that in six soils the catalytic action stood in almost 

 direct relation to the humus content ; Sullivan and Reid,^ 

 however, did not find this correlation to hold. Both 

 organic and inorganic substances are involved in this 

 property of soils, but the forms in which they operate 

 are not well understood. In the .main productive soils 

 have a strong catalytic effect and very poor soils are weak 

 in this respect, but this correlation also is not constant. 



iKonig, J., Hasenbaumer, J., and Coppenrath, E. Einige 

 Neue Eigensehaften des Ackerbodens. Landw. Vers. Stat., 

 Band 63, Seite 471-478. 1905-1906. 



2 Konig, J., Hasenbaumer, J., and Coppenrath, B, Bezieh.- 

 ungen zwisehen den Eigensehaften des Bodens und der Nllhr- 

 stoffaufnahme durch die pflanzen. Landw. Vers. Stat., Band 

 66, Seite 401--461. 1907. 



2 Sullivan, M. X., and Reid, F. R. Studies in Soil Catalysis, 

 U. S. D. A., Bur. Soils, Bui. 86. 1912. 

 2m 



