is especially needed by grain crops. Barnyard manure contains too little phosphoric acid. Its value is greatly increased by adding phosphate to it. Insoluble phosphoric acid like that in raw rock is made available to a considerable extent when mixed with manure, but it is not available alone. POTASH. Potash is taken from the soil by hay and straw more than by grain. It is not naturally deficient in most Ohio soils. It is particularly needed by some crops like potatoes and tobacco. Some dark "mucky" soils need it naturally. Selling straw, hay and fodder tends to exhaust the potash from soils. WORN-OUT SOILS. In building up worn-out soils complete fertilizers may be needed at first to get crops started, but the continued use of them when not accompanied by return of organic matter to the soil by manure or clover will leave the land in worse shape than in the beginning. "LOOKS" OF THE PLANT. The "looks" of the plants will often indicate what is lacking. Am monia promotes growth, and weak plants and light green foliage often go with lack of it, provided other conditions are right for growth. Lack of phosphoric acid and potash will sometimes show in character of grain as well as yield. Continued use of superphosphate (acid rock) tends to soil acidity. This can be corrected by lime or ground limestone. AMMONIA OR NITROGEN. BY E. E. SOMERMEIER. Chemist Ohio State University, Columbus, Ohio. Of the three essential fertilizer materials, ammonia, phosphoric acid and potash, ammonia is by far the most expensive. As has been already stated under "Analyses of Fertilizers," it is a chemical compound consisting of three parts by weight of hydrogen and fourteen parts by weight of nitrogen. Nitrogen is the portion that is of use to the plant. Free nitrogen is a colorless, odorless gas. Four-fifths of the air we breathe is composed of nitrogen. Combined with hydrogen, as has al ready been stated, it forms ammonia, a colorless gas having a strong, penetrating odor and readily soluble in water. Solutions of ammonia. in water are sold under a number of different names, as "ammonia,' "stronger ammonia," "spirits of hartshorn," "ammonia water," etc. The ordinary ammonia sold at the drug store should contain about 10% by weight of actual ammonia. Ammonia unites readily with acids to form salts. A well-known property of acids is the sour, acid taste, as the sour taste of vinegar or of lemon juice, etc. Ammonia unites with the sour constituent of vinegar or of lemon juice to form a light colored salt readily soluble in water. ORGANIC MATERIALS. Many organic materials, as dried blood, bone, peat, humus, etc., contain nitrogen not in the form of ammonia but combined with other elements in complex and various forms. These different forms of nitrogen differ greatly from one another in their ready solubility in water and hence in their value for agriculture purposes, as the plant can use only that nitrogen which is soluble. Hence only those nitrogen carrying materials are of value to the farmer which contain the nitrogen in a soluble form or which contain it in such a form that it decomposes readily and becomes soluble in water within a reasonable period of time. DETERMINING NITROGEN. In determining the amount of nitrogen in a substance, as in dried blood, the chemist changes the nitrogen to ammonia and determines it in this form and in reporting the result he may report the sample as containing so many per cent. of ammonia, although the nitrogen may not have been actually present in the sample as ammonia. What is meant and what should be understood by the result for ammonia in this report, is that the sample contains nitrogen which if expressed as ammonia equals the percentage given under the heading of ammonia. TERM AMMONIA INCLUDES ALL NITROGEN. The use of the term ammonia to include all nitrogen in the sample is in everyday use in the trade. The market quotations for dried blood for example being given as follows: "Dried blood, 12 to 13% ammonia, $3.00 per unit." This means that dried blood containing nitrogen equivalent to 12 or 13% of ammonia is selling at $3.00 for each unit (20) pounds) of ammonia. RELATION BY WEIGHT. The relation by weight between nitrogen and ammonia is 14 to 17, and in any case if the result given in per cent. of nitrogen is desired as per cent. of ammonia it is obtained by multiplying the nitrogen per centage by 17-14 or vice versa, if the result given as ammonia is wanted in terms of nitrogen, the per cent. of ammonia multiplied by 14-17 gives the equivalent nitrogen, hence dried blood containing the equivalent of 12% ammonia might be stated as dried blood containing 14-17 of 129.9 of nitrogen. REQUIREMENT UNDER NEW LAW. In recognition of the fact that all the nitrogen in fertilizers is not actually in the form of ammonia, and that the forms other than ammonia are not all equally valuable to the farmer, the Legislature enacted as a part of the fertilizer law a reqiurement that the manufacturer indicate the source of nitrogen in order that the purchaser may know whether or not he is buying nitrogen in a readily available form. FORMS OF NITROGEN. For purposes of further explanation and discussion these may be grouped into three classes. (1) NITROGEN AS NITRATES, chiefly as sodium nitrate or Chili saltpeter. This salt contains approximately 16% of nitrogen corresponding to approximately 19% of ammonia. It is very readily soluble in water and hence quickly available to the plant for food. (2) NITROGEN IN THE FORM OF AMMONIA, chiefly ammonium sulphate. This salt contains approximately 21% of nitrogen corresponding to about 25% of ammonia. Like sodium nitrate it is quickly soluble in water and is readily available to the plant for food. (3) NITROGEN IN ORGANIC FORMS. As has already been stated, different organic materials from which nitrogen is derived differ very greatly in respect to the nitrogen availability. In some the nitrogen is soluble in water or the compound decomposes quickly and the greater part of the nitrogen becomes soluble, while in others the nitrogen remains almost wholly insoluble, and hence largely inert and worthless in so far as having any fertilizer value. SOURCES OF HIGH AVAILABLE NITROGEN. Some of the most important sources of high (or quickly) available nitrogen are as follows: bone, dried blood, slaughterhouse tankage, dried fish, cotton-seed meal, Peruvian guano. SOURCES OF LOW AVAILABLE NITROGEN. Some of the sources of low (or slowly) available nitrogen are as follows: peat, muck, untreated wool waste, sheep manure, garbage tankage. LABORATORY METHODS. A number of laboratory methods have been proposed to determine the relative value of the nitrogen in these different materials, the results obtained by these methods being compared with the results obtained by crop tests. The laboratory methods for determining the solubility of organic nitrogen most used are known as the alkaline permanganate method, the neutral permanganate and the pepsin hydrochloric acid method. The alkaline method has been adopted by New York, New Jersey and the New England states, while a number of the southern states use the neutral method. LABORATORY TESTS INDEX OF AVAILABILITY OF NITROGEN. The details of these laboratory tests are of no special interest to the purchaser of fertilizers but the results obtained are of very direct interest. The results obtained by the laboratory tests are an index of the availability of the nitrogen for plant food as shown by crop tests and hence the laboratory results serve as an index of the real value to the purchaser of the nitrogen in different materials. Some values are es follows: With ammonia worth 17 or 18 cents per pound it behooves the farmer to know whether he is paying for ammonia (nitrogen) which the crops can use or whether he is buying it in the form of peat, muck, etc., in which most of it is not available. When buying, a safe motto is, "Buy high grade fertilizers" and avoid chances of paying for ammonia (nitrogen) from a large amount of peat and muck filler and also save the freight, hauling and sacking expenses on several hundred pounds of material, the value of which to say the least is questionable. *Street, Journal of Industrial and Engineering Chemistry, July, 1910. PRESERVE NATURAL SOURCES OF AMMONIA. In addition to the use of nitrogen or (ammonia) in the form of commercial fertilizers it can and should be supplied to the soil by means of clover, cow peas, soy beans and other similiar crops. These plants are able to take the nitrogen from the air and change it into forms available for plant food. Barn-yard manure contains an appreciable amount of ammonia in a readily soluble form and hence quickly available for usc. However, this ready solubility often is the cause of the farmer losing many dollars worth of fertilizing materials by allowing this soluble portion of the manure to be wasted and hence allowing the waste of the most valuable ingredient-the ammonia. Good farming in part consists in preserving the natural sources of ammonia on the farm by saving and use of manure and the growth of proper plants in rotation. and nitrogen (ammonia) should only be purchased on a farm in the form of commercial fertilizers where farm sources are insufficient or are not properly available. FILLER OR MAKE-WEIGHT MATERIALS. BY E. E. SOMERMEIER. Chemist Ohio State University, Columbus, Ohio. HIGH GRADE RAW MATERIALS. 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. 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 1-3% ammonia and 50-60% bone phosphate (22.927.5% phosphoric acid). Acid rock phosphate containing about 14% available phosphoric acid. For more complete list see "Fence Rails," page 63 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. |