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 .(_/v-Xk_tu^».^V^ — 
 
 UNIVERSITY OF CALIFORNIA Agricultural experiment Station 
 
 College of agriculture e- J- wickson. director 
 
 BERKELEY, CALIFORNIA 
 
 CIRCULAR No. 56 
 
 (August, 1910) 
 
 WORTHLESS FERTILIZERS 
 
 My attention has from time to time been drawn to articles in 
 papers and periodicals and to advertising literature, concerning the 
 alleged value of various naturally occurring rocks and mineral de- 
 posits as fertilizers. Such of these as I have been able to investigate 
 have been found totally without merit ; and investors either in the 
 material or in the stock of companies designed to exploit the deposits, 
 run grave risk of financial loss. 
 
 It should be pointed out in the first place that few materials of 
 this kind have any agricultural value, until they have been refined 
 as in the case of nitrate or potash deposits, or so treated as to convert 
 comparatively inert constituents into a form that will admit of their 
 being taken up by plants, as in the case of phosphate rocks. At 
 the present time the raw material for the manufacture of nitrate of 
 soda is found in Chile ; Germany furnishes the potash deposits ; and 
 the phosphate rocks suitable for manufacture are found in Northern 
 Africa, the Southeastern States and in a section comprising the south- 
 western part of Wyoming, the southeastern part of Idaho and north- 
 ern Utah. Up to the present no local deposits of any of these materials 
 have been extensively utilized for manufacturing purposes. And 
 so far as I am aware, no such local deposits of sufficiently high grade 
 have been developed to enter into competition with those from the 
 above mentioned sources. 
 
 The idea has frequently been advanced that certain common rocks, 
 notably those containing potash feldspar, should be of value as fer- 
 tilizer because of their content of potash. When we consider the 
 relatively stable and inert character of the complex silicates and the 
 further fact that these are alread}^ present in large quantities in 
 natural soils, it is difficult to see how applications of such materials 
 would result in any immediate or important crop increase. 
 
 The well known fact that lava rocks have frequently broken up 
 into fertile soils within a very limited period is used as an argument 
 to prove that lavas should make a good fertilizer. This, however. 
 
does not follow. A mineral fertilizer to^^be^^oii^fe tire cost of /{ipif)li- 
 cation should contain relatively large ^m(iujnLtsj§pLo,^ or Inore of the^' 
 so-called ''plant foods" in a compam^Ciyely emily^olublC'Co'iiditidn. 
 To furnish an amount of actual potash^eqiiivafenf 'tu"that in a^ri ordi- 
 nary application of sulfate of potash would require a relatively enor- 
 mous quantity of ground lava of average composition. In addition 
 the condition in which potash, the essential constituent, is combined 
 with the other rock constituents is such as to justify little hope of its 
 being utilized by plants within a reasonable period of time. Potash 
 insoluble in water, as it occurs in such materials, has no standing 
 among reputable agriculturists nor under the laws of the several 
 States. 
 
 Exploiters of worthless materials seem to have two methods of 
 working: one is by the use of testimonials from real or fictitious 
 persons who are supposed to have used the substances with advantage ; 
 the other is by the quotation of chemical analyses. The first is subject 
 to all the abuses of a patent medicine testimonial and in the second 
 case the uninformed investor is awed by an array of figures which 
 he does not understand and cannot interpret. Furthermore, the 
 layman is apt to be impressed by the reputation of the chemist who 
 made the analysis. This is a grave error because reputable chemists 
 frequently make analyses of samples of material, the source of which 
 is unknown to them. It is, accordingly, easy to quote a correct 
 analysis of a high grade sample as applying to lots of goods or de- 
 posits which they do not represent. Even well intentioned persons 
 in taking samples tend to select the best specimens and fail to realize 
 that these may not represent the deposit as a whole. 
 
 The purchaser of materials intended for use as fertilizer should 
 understand that the sale of fertilizers in California is regulated by 
 law and licensed by the State. All legitimate fertilizer manufac- 
 turers and dealers handling goods not licensed by others are regis- 
 tered with the Fertilizer Control of the University of California. 
 For their own protection consumers should see that all goods pur- 
 chased by them bear the name and registry number of the manu- 
 facturer. Attempts to sell unregistered and possibly worthless mate- 
 rials should be reported to the Fertilizer Control. 
 
 The prospective purchaser of stock in companies designed to work 
 mineral deposits should bear in mind that, with the exception of 
 high grade gypsum, there are few naturally occurring minerals which 
 can be profitably applied directly to the soil as fertilizers even when 
 finely ground. The manufacture of fertilizers is a complex business, 
 requiring technical skill and for most classes of goods considerable 
 capital. No person should buy stock of such co^ipanies unless he is 
 absolutely sure of the skill and integrity of the promoters and has 
 ex])crt advice as to the suitability of the proposed raw material as a 
 constituent of fertilizers. 
 
 John S. Burd, 
 
 Cheinist in Charge, Fertilizer Control, 
 
 University of California.