AORICULTL KAL APPROPHIATION llll.l^ 11»24. 277 



not come from very j^reut doptlis. Five lnindnMl foot, of course, is 

 just u fi^^uro, hut at loust from jjrojil (lt'|)ths. 



I)()ct(tr WiiiTNKV. Wv Imvc nlkuli salts which we hfiiovo luive 

 come from a very {^real drpfli, iinirh di'cpcr ih)in \vc ha\i' t-vrr sup- 

 posed heretofore. 



FOR rilYSICAL INVKSTICATIOXS OF IMroHTANT ri{OI'KKTIE« OF SOII^S. 



Mr. Andkuson. We will take up the next item on page 193. 

 Apparently the only tliin;; which distitif/uishes this from the prec<'ding 

 item is that this has to do with physical investin;ations ? 



Doctor WiiiTNKY. Yes, sir; out re(juirin<^ (liircrent methods and 

 dilferent men, men of dilferent training, and it supplements the 

 other. Both the chemical and physical investigations, of course, are 

 hased largely upon our soil surveys. 



Mr. Andkuson. We will take up the next item on page 194. 



FOR INVESTIGATION OF FERTILIZKR RESOURCES. 



Doctor Whitney. For the investigation of fertilizers? 



Mr. Anderson. Yes. 



Doctor Whitney. We have had a very favorable year in our work 

 on flie study of fertilizer stock, and fertilizer materials. .\s I have 

 explained to the committee, it is divided into nitrogen work, phos- 

 phoric acid, potash, and miscellaneous soil amendments, such as 

 lime, etc.. and we have made very good progress. I think I told the 

 committee last year that we have been working for some time on 

 concentrated fertilizers. The trade, the farmers, and the experiment 

 station workers have all realized for a lon^ while that concentrated 

 fertilizers arc cheaper and more economical. With the introduction 

 of nitrogen fixation methods, which started in Germany and have 

 been most largely developed in Germany — in the fLxation of atmos- 

 pheric nitrogen into ammonia gas — we have got to make certain 

 products that are not adapted to the chemical mixtures that our 

 industry has been putting out in the past. 



They have been using a great deal of waste products, and they have 

 been making a rather dilute form of acid phosphate. They have 

 been making it with Ki per cent, whereas the rock as it is in the 

 ground carries 32 or more per cent. Their method of converting the 

 rock phosphate into acid phosphate dilutes it approximately one- 

 half, so that we get a weaker product than we had in the mine. Then 

 our method of mining the rock for treatment with sulphuric acid has 

 been a very wasteful one, because we have only been able to use the 

 purer form of rock and have thrown on the dump about Go per cent 

 of the phosphorus we have mined. But with this methotl of vola- 

 tilizing the phosphoric acid, which we have developed in the bureau. 

 we are able to use the run-of-mine rock, thus saving the material 

 that now goes to the dump and cutting out the expenses of the origi- 

 nal preparation, because we use a lower-grade material. 



M^r. Andehson. Is anybody using tiiis new process now? 



Doctor Whitney. Yes, sir; there is a concern at Birmingham. Ala., 

 which is using it for the preparation of phosphorus, for the prepara- 

 tion of phosphate salts, first for food products and incidentally as 



