276 AGRICULTURAL APPROPRIATION BILL, 1924. 



biochemical chancres in soils; we have shown their interrelation and 

 the control we have of them through drainage, irrigation, cultivation, 

 and cropping. In the chemical investigations we have been studying 

 the properties of the soil colloids. It is the material that causes soils 

 to shrink or contract when dry or wet; it is the material that holds 

 the grains together and makes them plastic or hard when dry, and 

 it is the seat of the absorbing power of soils for moisture and for gases, 

 and is the seat of the important chemical changes that ^o on in the 

 soil from releasing the so-called mineral plant foods and is the home 

 of the biochemical changes that are essential to a healthy soil. 



Mr. Anderson. What direction are your investigations taking 

 now *. 



Doctor Whitney. Well, we have the material out; we are writing 

 up now and have nearly ready for publication methods for deter- 

 mining the amount of colloids in soils. Tliat is something we have 

 never hail before. There are some peculiarities about the methods 

 due to some peculiarities about the colloids, but we have methods 

 to propose for determining the amount of colloids in soils. Then the 

 constitution of these colloids is a subject that will require a great 

 deal of research. 



Mr. Anderson. If I should send you a sample of soil from Min- 

 nesota what could you tell me about it ? | 



Doctor Whitney. I could tell 3'ou the amount of colloids in it. 



Mr. Anderson. That would not mean anything to me. j 



Doctor Whitney. Well, it would mean a great deal to us in the ? 

 advice we would give you as to the treatment of the soil and as to 

 its adaptation. Of course, that is not all. I am not claiming that 

 this is the one thing that makes soils productive or nonproiluctive, 

 but it is the missing Uiik that the world has been lookino^ for to 

 bring all of these properties into their proper relationship. Oi course, 

 as I nientioneil last year, we have a very small appropriatiiui for the 

 study of the chemistry of soils. We are not only working on the 

 constitution of soils but we are working on the composition of soils 

 at considerable depth below the surface. We are finding more and 

 more tiiat in onhM' to understand the surface soil we have got to find 

 out what there is in the deep depths. We have frei[uently heretofore 

 worked on material at 6 feet oelow the surface but now we want 

 to go 100 feet or 1,000 feet, if we can get samples. Then we are 

 doing a great deal of routine work for the other bureaus anil other 

 di'Mjirtnients. 



Sir. Buchanan. Is it your iiU^a that the character of the soil 100 

 feet deep or ')00 feet deep l\as an inlleunce upon the surface soil? 



Doctor Whitney. Yes; we think it has. 



Mr. Buchanan. Even though there are watercourses and rock 

 between them >. 



Doctor WinTNKY. Yes. We do not think it has an ellVct to-ihiy, 

 but we tliink it has had an effect in the past ages in modifying the 

 present soils we are working with. 



Mr. Br< MANAN. In past ages the soil 100 feet ilown might have 

 i»een surface soil { 



Doctor Mauiu t. Doctor Whitney has in mind the fitrmation of 

 caliche, whiith is so abundantly distributed over Southwestern Texas, 

 and the question has i)i'(>n legitimately raised as to whether that 

 caliche, which is now close to the surface and a part of the soil, diil 



f It 



