Physics: 12 



sand? Also, will the amount of water present not be critical because 

 with more water there may be less loss of the fumigant by adsorption? 



A. Adsorption is a function of surface and, of course, in a clay system 



the amount of svirface is tremendously greater than on coarser soil 

 particles. Naturally, gas adsorption would be much, much greater in a 

 clay soil than in a sandy soil. If your problem is, as Dr. Jones pointed 

 out, one of getting the gas in solution, rather than having it adsorbed 

 on the surface, then the presence of moisture is important. You would 

 have to fumigate at a higher moisture content in clay soil than in a 

 sandy soil, as far as percentage moisture is concerned, in order to pre- 

 vent the adsorption from occurring. 



