Judsonia weekly advance., 1917-03-21
WHAT'S WHAT IN
 GOOD FERTILIZER
Information About Commercial Fertf iizers Which Is Worth Keeping
 For Reference.
By De F. Hungerford, College of Agri-
 culture, Fayetteville

By De F. Hungerford, College of Agri-
 culture, Fayetteville.
 Fertilizers are materials that SUD- ply one or more of the three most important plant food elements-nitro- gen, phosphorous and potassium.
 Nitrogen Fertilizers.
 The common nitrogen fertilizers are nitrate of soda, sulphate of am- monia, cotton seed meal, dried blood, l tankage and cyanamid.
 Nitrate of Soda contains from 15 to 1 16 per cent of nitrogen. It is soluble in water and therefore immediately available to the plants. The amounts applied vary from 100 to 400 pounds per acre. Because of its solubility it should be applied either. at seeding 1 time or as top dressing after the crop has come up. If used as a top dressing it should be put on while the plants are dry for otherwise the leaves may be burned. Recent tests have shown thatnitrate of soda is very beneficial to apple trees when applied at the rate of five or six pounds per tree when the flower buds begin 10 show a pin color.
 Sulphate of Ammonia Is by-prod- uct in the manufacture of coke and coal gas. It contains about 20 per cent of nitrogen, which Is nearly as readily available as that in nitrate of soda. It is used at about the same rate per acre and in much the same manner as nitrate of soda. Sulphate of ammonia should not be used on acid or sour land unless lime is ap- piled with it to overcome the acidity.
 Cotton Seed Meal has been used very extensively in the South as a fertilizer, but it is coming into such general use as stock food that only the inferior grades can now be used profitably. The nitrogen content ranges from to ' per cent, and it contains in addition 2.5 per cent of phosphoric acid and IF per cent of potash. The nitrogen is not soluble and must decay in the soil before 1t can be utilized by plants. For this reason application should be made one or two weeks before the crop is planted
 Dried Blood and Tankage are not soluble in the soil water and, like cot ton seed meal, must be applied a week or more before planting time. Neither is used as extensively now as formerly. Dried blood contains from 10 to 13 per cent of nitrogen. Tankage is more variable. It's nitrogen content ranges from to 12 per cent and phosphoric acid from 2 to 20 per cent.
 Phosphorous Fertilizers.
 The important phosphorous fertilx- CTS are acid phosphate, raw and steamed bone meal, basic slag, bona tankage and raw rock phosphate.
 Acid Phosphate is ground phosphate rock treated with sulphuric acid. There are three grades containing re- spectiyely 12, IA and 16 per cent phos- phoric acid. Although the phosphorus in acid phosphate is readily available and can be taken up by the plant as soon as it is applied, it is not leached out, because the soil absorbs and holds phosphorus until the plants need 1t. The rate of application is from 200 to 400 pounds per acre. Acid phosphate gives the best results on heavy clay land and on soil that, is not acid.
 Ground Bone in the natural con- dition contains about per cent of l nitrogen and about 22 per cent of phosphoric acid, but the ma terial ordinarily sold as fertilizer has been steamed to remove the fat ! and glue which takes out most of the | nitrogen. The result is ma terial with from "A to 27 per cent of phosphoric acid and 1-2 to ? per cent of nitrogen Bone phos- plates are not so available as acid phosphate and give best results on meadows and pastures.
 Basic Slag Phosphate Is a by-prod- uct from the manufacture of steel It { contains from 15 to 19 per cent of phosphorAc acid and from 35 to 50 per cent of hSae. The, phosphorus is more available, than in bones, but less available than in acid phosphate. The lime content makes it good fertt-