ARTIFICIAL FERTILIZERS.

Northland Age, Volume 2, Issue 49, 10 July 1906, Page 8

ARTIFICIAL FERTILIZERS.

THEIR FUNCTIONS AND USE. — 4By F. E. Lee, Assistant to the Chemist for Agriculture, in the .Victorian "Journal of Agriculture."- —« ~ POTASH.; Potash manures are perhaps the least used of all forms by the average farmer, and, as a consequence, there is little or no knowledge of its commercial forms and action in the soil. It by no means follows that because it is infrequently used that it has any inferior value to the other plant foods. On the other hand, polassie manures should occupy a dominating influence in the fertilization of soil for the growth of such crops as legumes, fruit and root crops. It is advised, however, that fertilizers containing potash should always be used in conjunction with other manures, their best effects, not being so apparent when used singly. It is not so many years ago that practically the only source of potash was wood ashes ; since, however, the discovery of enormous deposits of potasli at Stassfurt, in Germany, the world's supply is now drawn from that source. The commercial forms in which potash is sold are :—Muriate of potash, or potash chloride, sulphate of potash, and kainit, all of which are imported from Germany. There is a potassic manure sold under the name of Australian potash, which comes from the burning of refuse molasses from sugar refineries, the potash contained therein principally as carbonate and chloride of potash. The functions of the potash may in a general manner be described as influencing the quality of agricultural products rather than the quantity. For such crops as fruit, potash affects the quality, flavour, and aroma, increases the percentage of starch in potatoes, improves the burning'qualities of tobacco leaf, and promotes the formation of sugar in sugar-cane and sugar-beet. Maize, lucerne, peas and beans also respond to the action of potassic manures. Experiments with potash, used in combination with other fertilizers, have been made by the Department on a variety of crops, the results of which will be set out in future articles. As with .nitrogenous fertilizers, fertilizers containing potash must be used with a certain amount of caution and intelligence ; otherwise the results may not be satisfactory,. For example, some forms of potassic fertilizers are said to exorcise a deleterious effect when applied to certain crops. Potash chloride may give rise to "stagginess" in potatoes,, although this is a debatable point ; may lower the burning qualities of tobacco leaf, and may prejudice ihe formation of sugar in the beet. For these crops named it would be wiser to use the- sulphate of potash. Kainit which, by the way, is a form of potassic fertilizer perhaps more frequently made use of than the more costly chloride and sulphate forms, contains in addition to a limited amount of potash, chloride or sodium, or common salt, and magnesia. It may not be the desire of some users of kainit to add salt and magnesia to their soils, in which case other forms of potash should lie used in preference. It is claimed that one virtue of kainit is its hygroscopic power, or property of absorbing moisture from the air, which renders it iof value on dry sandy soils. As an exterminator of grubs and similar pests which infest some soils, it has a certain, vanio better appreciated in Europe than in Australia. Compared, however, with muriate and sulphate of potash, kainit is, relatively speaking, the most costly form in which a definite amount of potash can be bought. It would be more serviceable and more economical to use approximately onefourth the amount of the more expensive forms.

In the northern grain areas, potash judging from the results of experimental fields, does not, up to the present time, justify its inclusion in the manurial dressing. Wheat, above all crops, can thrive with relatively small amounts of potash, and, furthermore, the common practice of burning stubble gives back to the soil some of the potash removed by the crop. I propose in another article to go elaborately into the question of burning stubble, and hope to show that the practice is an extravagant one, viewed from a different stand-point to which the average farmer usually regards it. OTHER CONSIDERATIONS. It would be an omission in any discussion on artificial fertilizers if some mention were not made as to the "mechanical condition" of these substances.' The user of fertilizers demands that, besides an article of good quality, it shall be in such a condition of fineness that there shall be no hindrance to its free flow from the drill. An excessive percentage of moisture in a fertilizer lowers its apparent quality, and adds unduly to its weight ; hence the importance, from a purchaser’s point of view, of taking note of the moisture content of ail fertilizers offered for sale. In the purchase of bone-dust or bonemeal, there is even greater necessity than with mineral manures that the "mechanical condition," or percentage of "fine" and "coarse" material should be stated. The recently passed Artificial Manures Act requires that the percentage of "fine" and "coarse" material shall be stated oil the accompanying certificate. "Fine" material, it may be added, is that portion that passes through a sieve having fifty, meshes to the linear inch and "coarse" is the portion which does not pass through a sieve of the above mesh.