2 BULLETIN 150, U. S. DEPARTMENT OF AGRICULTURE. 
In a previous report on the Menhaden Fish Fertilizer Industry of 
the Atlantic coast, 1 the fish-fertilizer resources of the Atlantic coast 
have been discussed. In the introduction to that report the contri- 
butions from this bureau on the subject of fertilizer resources of the 
Nation are mentioned. Since the completion of that report, Wagga- 
man has reported on the phosphate fields of South Carolina, 2 the 
utilization of acid and basic slags in the manufacture of fertilizer, 3 and 
the possible commercial utilization of nelsonite. 4 Free has described 
the topography of the desert lake areas, 5 while Young has discussed 
the chemistry of the salines of that region. 6 Crandall has continued 
his study of the kelps of southern California, and Frye 7 and Rigg, s 
during the summer of 1913, surveyed the kelp groves of southeastern 
and western Alaska, respectively. Cullen, Lindemuth, Merz, and 
Parker have studied further the composition of kelps. 9 Cameron 
has reviewed the sources of potash in the United States. 10 Ross has 
studied the decomposition of feldspar, 11 and Smith the value of 
sponges as fertilizer. 12 Gardiner has determined the potash content 
of certain muds from sugar refineries, 13 and the writer has surveyed 
the nitrogenous resources of the United States. 14 
Present agricultural practice prescribes the use of three chemical 
elements as a " soil amendment," a " stimulant for plant growth," or 
a " plant food," as it is variously put. These three elements when 
applied to the soil in which a crop is growing have been found by 
practice to afford an increased crop yield. They are phosphorous, 
potassium, and nitrogen, spoken of by the respective trade terms 
of phosphoric acid, potash, and " ammoniates." In the commercial 
fertilizers phosphoric acid is found in the form of calcium phos- 
phate, which is bone phosphate or rock phosphate, usually treated 
with sulphuric acid to render it soluble. Potash is found as a salt or 
salts of potassium, either sulphate or chloride, and the " ammoniates," 
1 Bui. 2, U. S. Dept. of Agr. 
2 Bui. 18, U. S. Dept. of Agr. 
3 Bui. 95, U. S. Dept. of Agr. 
4 J. Ind. Eng. Chem., 5, No. 9, Sept., 1913. 
5 Bui. 54, U. S. Dept. of Agr. 
6 Bui. 61, U. S. Dept. of Agr. 
7 Kept. 100, L T . S. Dept. of Agr., Parts IV and V. 
8 Ibid. 
9 J. A. Cullen, On the Available Nitrogen Content of Kelp, J. Ind. Eng. Chem., 6, 581 
(1914) ; Merz and Lindemuth, The Leaching of Potash from Freshly Cut Kelp, J. Ind. 
Eng. Chem., 5, 729 (1913) ; Merz, On the Composition of Giant Kelps, ibid., 6, 191 
(1914) ; Parker and Lindemuth, Analyses of Certain of the Pacific Coast Kelps, ibid., 5, 
287 (1913). 
10 Possible Sources of Potash in the United States, Yearbook, U. S. Dept. Agr., 1912, 
p. 523 ; Kelp and Other Sources of Potash, J. Frank. Inst., Oct., 1913, p. 347. 
11 Decomposition of Feldspar and Its Use in the Fixation of Atmospheric Nitrogen, 
J. Ind. Eng. Chem., 5, 725 (1913). 
u Sponges as a fertilizer, ibid., 5, 850 (1913). 
"Ibid. 6, 480 (1914). 
14 Turrentine, The Nitrogenous Fertilizers Obtainable in the United States, Bui. 37, U. S. 
Dept. of Agr. 
