Transactions of RHASS Volume 1940 - Page 239
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| Year | 1940 |
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| OCR Text |
56 CHEMICAL DEPARTMENT. the price per ton of a sample of good material up to its guarantee, and therefore the proper price per ton of a manure is found by multiplying the price of the unit of the valuable ingredient by the percentage as found by analysis. If a manure contains more than one valuable ingredient, the unit value of each ingredient is multiplied by its per- centage, and the values so found when added together give approxi— mately the price per ton of the manure. Nitrate of soda contains no ammonia, but it contains nitrogen, and 14 units of nitrogen are equivalent to 17 units of ammonia. The commercial values of manures are determined by means of the UNITs in the following manner :— Take the results of analysis of the manure, and look for the following substances :— Phosphates dissolved (or soluble plies- phoric acid) Phosphates undissolved (or insoluble phosphoric acid) Total phosphoric acid Nitrogen Potash Should the results of analysis or the guarantee not be expressed in that way, the chemist or the seller should be asked to state the quantities in these terms. Suppose the manure is ground mineral phosphate—— The proportion of phosphate present in a sample guaranteed to contain 26 per cent phosphoric acid may be 21 per cent phosphoric acid. The price per unit of phosphoric acid in ground mineral phosphate (26 per cent grade) is 2s. Hid. The value of ground mineral phosphate contain- ing 24 per cent phosphoric acid is therefore 24 times 23. Mid, equal to £3, 10s. Gd. Suppose the manure is a superphosphate—say an ordinary superphos- phate, 17 per cent soluble phosphoric acid,——the price per unit of phos- phoric acid in superphosphate (18 per cent grade) is 4/83}. It is valued thus— Soluble phosphoric acid. 17 times 4/83,, equal to £4, 0s. 5d. Insoluble phosphoric acid is not valued in a superphosphatc. Suppose the manure is a compound fertiliser containing 4 per cent nitrogen, 7 per cent soluble phosphoric acid, 3 per cent insoluble phosphoric acid, and 4 per cent potash. From the units given on p. 55 for “Mixtures and Compound Manures,” the value Of this compound fertiliser is obtained as follows :— No other items but these are to be valued. The value Of the— Nitrogen will be . . . £1 10 0 per ton Soluble phosphoric acid will be . 1 14 1 ,, Insoluble phosphoric acid will be . O 10 O ,, Potash will be . . . . . O 17 8 ,, £4 ll 9 The value of this manure will thus be £4, 118. 9d. per ton, exclusive of the cost of mixing, bags and bagging, which may be taken on an average at about 20/6 per ton. It will be seen that the potash is valued on the assumption that it is derived from muriate. Note—The units have reference solely to the MARKET PRICES of MANURES, and not to their AGRICULTURAL VALUES. CHEMICAL DEPARTMENT. ‘ 57 TABLE OF COMPENSATION VALUES FOR 1940. TABLE SHOWING THE VALUE OF FEEDING~STUFFS as MANURE PER TON, AND THE COMPENSATION VALUE PER. TON OF FOOD CONSU'MED, BASED ON THE AVERAGE UNIT Pnlcns or FERTILISERS FOR 194-0. The following is a Table showing (under Section A) the average proportions of nitrogen, phosphoric acid, and potash present in the feeding-stuffs named. The Table also shows the value per unit of nitrogen, phosphoric acid, and potash, the prices per unit being the value per unit for compound manures prevailing for 19-l0. The residual value of nitrogen is again based on the total nitrogen content of the feeding-stuffs instead of being divided into digested and undigested nitrogen. Under Section B of the Table is shown the compensation value per ton of food consumed for each of the feeding-stuffs named, based on the unit prices for 1940. Column (1) of Section B of the Table shows the value per ton recovered in dung; while the remaining two columns show the residual values per ton after one crop and two crops have been removed. The residual value, after one crop has been removed, is taken as one-half of the original residual value. Residual values are reduced by one-half after each crop. (t' "w" 'u ‘ |
| Title | Transactions of RHASS Volume 1940 - Page 239 |
