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Tankage

soil, cent, fertilizer and nitrogen

TANKAGE. Fertilizer produced from the offal of the abattoirs. Waste material such as tendons, intestines, lungs, hair, trimmings of hides, bones, horns, hoofs and some blood are the chief component parts of tankage. Hair and hide trimmings are now barred because they are practically indestructible and retain their form in the soil for years. It is treated with superheated steam under pressure to remove fat and gelatine, then mixed with a little slaked lime to prevent rapid fermentation. It is then dried and crushed. If little or no bone is present the product is termed meat tankage. Tankage varies considerably in its composition, sometimes containing as much as 12 per cent nitrogen in meat tankage and in bone tankage up to 9 per cent nitrogen with 7 per cent phosphoric acid. Tankage is a slow acting excellent fertilizer; in bone tankage its value as a direct crop-producer is dependent largely on the fineness of the grinding. Of course the nitrogen acts in exactly the same manner on the soil as meat. Comparative,' tankage contains less nitrogen than dried blood but more phosphoric acid. The considerable variation in its composition is exposed by the following table, taken from Snyder's 'Soils and Fertilizers,' all from one factory: 1st Year 2d Year 3d Year Moisture per cent 10.5 9 8 10.9 Nitrogen 5.7 7.6 6.4 Phosphoric Acid " " 12.2 10.6 11.7 In a general way 5 to 8 per cent of nitro gen can be expected and from 5 to 12 per cent phosphoric acid. In its action on the soil it is slower than dried blood. It is an excellent

garden fertilizer and is also used for field crops in proper rotation and as a top-screening for sod land. As tankage in its full strength should not be allowed to come in contact with seed it is usually applied several days before planting operations, or else a special fertilizer and seed drill is used which places it near but not in contact with the seed. Two hundred and fifty pounds per acre is computed as a good dressing, but as high as 400 pounds can be safely applied under certain conditions. In dry weather an excessive application (say 800 pounds) will destroy vegetation. Of course the strength of fertilizer advisable must be calculated according to the composition of the soil; where the soil is badly impoverished a larger proportion of tankage can be usefully applied than on one kept up in good quality. Because of its comparatively slow action tank age should be used in as finely ground condition as possible and should be applied to the soil with a view to its permanent benefit rather than as a direct food for a certain crop. Tank age of a certain type and content is also utilized as a hog-feed with good results when mixed with corn or other food rich in carbo hydrates or fats but poor in protein content. It is also used for feeding dairy-cows and in preparing beef cattle for market. See FERTIL