BUREAU OF SOILS. 301 



fertilizer use; and as they contain the fertilizing elements in a much 

 more concentrated form than the relatively low-grade materials 

 which constitute the bulk of our present-da}'' fertilizers, a very great 

 economy in the matter of transportation may be effected by their use. 



It is a fact, however, that the chemical and physical properties of 

 these compounds, particularly as relates to their suitability for fer- 

 tilizer application, are but little understood, and this is especially 

 true as regards mixtures of these compounds. The urgent need of a 

 careful investigation of this subject, with -a view to preventing, as 

 far as possible, the loss of time and money that has been experienced 

 in the past in preparing otlier materials for use as fertilizers, can not 

 be too greatly emphasized. It is therefore desirable that a com- 

 plete study be made of (1) the chemical and phj'sical properties of 

 the compounds and their mixtures which it is proposed to use in the 

 manufacture of fertilizers, (2) the compatibility of these compounds 

 in mixture, (3) limits within which they may be mixed without 

 appreciable alteration in composition, (4) properties which interfere 

 with their storage, handling, and transportation, (5) methods for 

 ol)viating such properties as far as possible, and (6) suitable methods 

 of application. 



The preliminary work done by this bureau on this subject is de- 

 scribed in the scientific press and in several patents that have been 

 granted on certain phases of the work. Apart from this it would 

 seem that none of the problems outlined have yet received any 

 considerable attention. 



EXPERIMENTAL KELP-POTASH PLANT. 



The experimental kelp-potash plant, located at Summerland^ 

 Cal., began operations in a small way during the fiscal year 1918. 

 Dui-ing that year dried kelp and kelp char were produced and sold 

 on their potash content to the extent of $26,000, and studies looking 

 to the improvement of processes and the availability of by-products 

 were begun. During the fiscal year 1919 the production of dried 

 kelp and char was continued, the amount derived from the sale of 

 these two products covering operating expenses over considerable 

 periods of the year. In addition, the steady production of high- 

 grade potash salts was accomplished. Ex])eriments were also under- 

 taken looking to the manufacture of high-grade bleaching carbons 

 for use in sugar refining and in the removal of coloring matter from 

 a variety of organic liquids and solutions not susceptible to chemical 

 bleaching, for which there is a very large and remunerative demand. 



The end of the fiscal year 1919 found this plant and organization 

 at the end of its second year of operation. At that time kelp was 

 being dried, incineratod, and partly activated for the manufacture of 

 bleaching carbon, followed l)y leaching for the extraction of potash 

 and iodine, and partly leached without activation. The brine re- 

 sulting was being evaporated for the manufacture of potassium 

 chloride of about 80 per cent KCl content, and the portion of the 

 carbon which had been activated was being extracted and further 

 processed for the manufacture of bleaching carbon. The progress 

 made in the various lines of activity during the fiscal year just 

 dosed is discussed in the following paragraphs. 



