POTASH. BY E. E. SOMERMEIER, Chemist, Ohio State University, Columbus, Ohio. Potash is essential to vigorous plant growth, and complete plant nutrition requires the presence in the soil of potash in a form readily soluble in water and hence in a form available for the use of the plant. HOW IS AMOUNT OF POTASSIUM PRESENT IN A FERTILIZER ESTIMATED? The common soluble salts of potassium are potassium chloride, potassium sulphate and potassium carbonate. In estimating the amount of potassium present in a fertilizer it is customary to estimate it as being present in the form of potash which is the oxide (K2O) and which contains about 83 per cent. of actual potassium. In estimating the amount of potash equivalent to potassium in different forms the following values are convenient : VALUES. (a) One hundred parts of potassium chloride contain the equivalent of 63.1 parts of potash or the equivalent of 52.5 parts of potassium. (b) One hundred parts of potassium sulphate contain the equivalent of 54.0 parts of potash or the equivalent of 44.8 parts of potassium. (c) One hundred parts of potassium carbonate contain the equivalent of 68:1 parts of potash or the esuivalent of 56.5 parts of potassium. WHERE IS POTASH FOUND? Potash is a constituent of many common rocks and minerals, and most soils contain an abundance of potash which however is in many cases practically wholly in an insoluble form and hence of little or no value in plant growth. Ordinary granite often contains several per cent. of potash in the form of feldspar, an insoluble compound of potash, alumina and silica. Feldspar and rocks containing considerable percentages of potash are very common in various portions of the mountainous regions of the United States. In the aggregate these rocks contain the equivalent of many millions of tons of potash, which, however, from an agricultural standpoint is practically worthless, as the decomposition of such rocks by weathering is so slow (requiring very many thousands of years) that the amount of potash which becomes available during the life of the plant is practically infinitesimal. WHY DOES THE GERMAN GOVERNMENT PRACTICALLY CONTROL THE POTASH SITUATION? Deposits of the soluble compounds of potash, the compounds valuable for agricultural purposes, are limited to comparatively few regions, and at the present time the main and in fact the only commercially developed deposits of potassium salts are found in Germany. The German government has a monopoly of the potash production, and all potash imported into this country is subject to a tax. The annual importation of potassium salts into this country is in the neighborhood of 1,200,000 tons, of an average potash content equivalent to 25 per cent. of potassium chloride or equivalent to 300,000 tons of pure potassium chloride. Every pound of this product is taxed by the German government, which tax is of course indirectly paid by the American farmer who uses the fertilizer. The amount of tax which the German government can levy upon potash compounds is limited merely by what that government thinks it can safely apply without seriously interfering with the sales of the material or without bringing into existence methods and means for obtaining a supply of potash from other sources. This condition of being practically at the mercy of the German government is not pleasant, either for the American farmer or for the United States government, and numerous plans and investigations have been considered and undertaken both by private individuals and by the United States government, looking toward the obtaining of a potash supply from sources which would make this country independent of the German supply. At least three sources are possible. WHAT SOURCES AT OUR COMMAND TO OBTAIN SUPPLY OF POTASH IN THIS COUNTRY? (1) Chemical treatment of the insoluble compounds of potash and the conversion of this potash into a soluble form. (2) Discovery and development of the deposits of soluble potash compounds in the desert regions of the western part of the United States. (3) Recovery of potash from sea weeds. WHAT MATERIALS NOW CONTAIN INSOLUBLE COMPOUNDS OF POTASH? The obtaining of potash by chemical treatment of feldspars and rocks containing high percentages of potash is entirely feasible and the supply of raw material is practically inexhaustible. The only problem, but it is an important one, is to be able to produce the potash at a price low enough to compete with the price of the German supply. At the present time no commercial plants are in operation, but many well informed authorities express a faith in the ultimate commercial success of the method and believe that much of the potash in the coming century will be obtained in this way. HAVE WE DEPOSITS OF SOLUBLE POTASH IN THE UNITED STATES? Considerable deposits of potassium salts have already been discovered in the western part of the United States. At Searles Lake, California, a deposit estimated to contain from four to ten million tons of potash is being developed at the present time and doubtless new deposits will be discovered and developed in the near future. WILL SEA WEEDS AFFORD ADEQUATE SUPPLY OF POTASHI FOR ALL COMMERCIAL NEEDS? The recovery of potash from sea weeds apparently affords the possibility of a supply adequate for all commercial needs. Off the coast of Southern California are extensive beds or groves of giant sea weed or kelp which when dried contain about 25 per cent. of potassium chloride. The extent of these kelp beds or groves has already been determined as being sufficient to supply on a conservative estimate an annual production of one million tons of potassium chloride or upwards of three times. the amount annually used at present. This obtaining of potash from sea weed like the obtaining of potash from feldspar appears to be merely a question of being able to do so at a price which will make it commercially profitable. According to F. K. Cameron of the United States Department of Agriculture', a ton of dried kelp based on present values is worth about $10.50. The estimated cost of harvesting and drying a ton of kelp if done on a commercial scale is estimated at $2.70, leaving a margin of $7.80 per ton to cover freight charges, cost of sacking, profit, etc., from which it appears that the early development of this industry on a commercial scale may reasonably be expected. SUMMARY. Briefly summarized, the present potash condition is about as follows: The American farmer is dependent upon the German supply of potash. This supply is subject to a tax by the German government, which tax is paid by the farmers of the United States. Several other sources of supply are possible, and the possibility and probability of their development serves to limit the amount of tax which the German government can safely levy, and while this country for some years to come will undoubtedly pay tax on the bulk of the potash used, it does not appear that the tax will ever become so great as to make the price prohibitive, and the development of other sources of supply will undoubtedly enable the American farmer of the future to obtain potash on terms comparable with present prices. 'Journal of Industrial and Engineering Chemistry, Vol. 4, p. 690, 16-B, of A. THE COMPOSITION OF SOME MATERIALS USED IN THE MANUFACTURE OF FERTILIZERS. The following table gives the percentages of phosphoric acid, potash, and nitrogen, and ammonia equivalent to the nitrogen, in a number of raw materials used in the manufacture and compounding of fertilizers. The percentages given usually represent the average and in many cases individual samples will vary considerably from the figures given. FILLER OR MAKE-WEIGHT MATERIALS. BY E. E. SOMERMEIER, Chemist, Ohio State University, Columbus, Ohio. HIGH GRADE RAW MATERIAL. Some of the principal raw materials of which high grade fertilizers are composed are as follows: Sodium nitrate containing the equivalent of about 19% ammonia. Dried blood containing the equivalent of 12-13% ammonia. Tankage containing the equivalent of 9-11% and 15-20% bone phosphate (6.9-9.2% phosphoric acid). Ground bone containing about 4% ammonia and 50% bone phosphate (22.9% phosphoric acid). Steamed bone containing 14-3% ammonia and 50-60% bone phosphate (22.9-27.5% phosphoric acid). Acid rock phosphate containing about 14% available phosphoric acid. For more complete list-see "Table of Composition," page 81 of this report. A fertilizer made by simple mixture of these materials cannot help being relatively high in one or more of the fertilizer ingredients, ammonia, phosphoric acid and potash. LOW GRADE FERTILIZERS. In order to make low grade fertilizers as 1-8-2, 1-9-1 grades, etc., the manufacturer must put in a "filler" or "make-weight" material, or what amounts to the same thing, use lower grade raw materials. For example, a ton of 1-8-2 fertilizer may be made from the following amounts of materials: Tankage (10% ammonia and 5% available phosphoric acid). Acid phosphate (about 14% available phosphoric acid)--- Filler of sand, dirt, cinders, etc--- Total Either mixture a, b or c contains 1% ammonia, 8% phosphoric acid and 2% potash. |