12 DEPARTMENT OF AGRICULTURE. 



Kainit is a crude yellowish-red salt containing about 12.5 per cent, of actual 

 potash which is largely in the form of sulphate. Along with it are large quantities 

 of common salt and small percentages of chloride and sulphate of magnesia. 



Sylvinit. This salt when ground is much more red in colour than kainit. It 

 is sometimes sold by fertilizer-manufacturers under the name of kainit. It consists 

 chiefly of chlorides, being principally composed of sodium chloride and potassium 

 chloride. 



Muriate of Potash. Muriate of potash or potassium chloride is more generally 

 used than any of the other salts. It varies somewhat in composition, according to 

 the method of manufacture, but the product most commonly met with contains 

 about 50 per cent, of actual potash. The principal impurities are common salt and 

 certain insoluble matters which are not injurious. All the potash is immediately 

 available. 



Sulphate of Potash. This is a yellow, dry, almost powdery substance. It is sold 

 from 90 to 95 per cent, pure and therefore contains an equivalent of from 48 to 51 

 per cent, of actual potash. It is more expensive than muriate, but is more adapted 

 for certain .crops, such as tobacco and potatoes, crops injured by excessive chlorides. 



Double Sulphate of Potash and Magnesia. This product is somewhat similar to 

 high-grade sulphate of potash in its effect on crops. It usually contains 26 per cent, 

 actual potash. 



Potassium Magnesium Carbonate. This is a dry white manufactured product 

 and is an excellent source of potash for crops injured by chlorides. It contains 20 

 to 25 per cent, actual potash. It is not sold extensively. 



Wood-ashes. The potash in wood-ashes is in the form of carbonate, which is 

 very desirable for all plants. Good unleached ashes should contain 5 to 6 per cent, 

 of potash. Leached ashes or ashes that have been exposed to the weather usually 

 have lost all but one-half of 1 per cent, of their potash. But they contain some 

 phosphoric acid and 25 to 50 per cent, of the whole material is carbonate of lime. 

 This phosphoric acid and lime remain unchanged by weathering and leaching. 



Seaweed. The practice of using seaweed as a fertilizer is very old. During the 

 war greater attention was paid to the value of this material owing to the scarcity 

 of other potash fertilizers. In the fresh state the Pacific Coast seaweed contains 

 almost as much nitrogen and more potash than farmyard manure. The analysis of 

 dried samples proved to contain over 12 per cent, potash. Seaweed ash samples 

 contained as high as 30 per cent, actual potash. Its value, applied either in the 

 fresh, dried, or burnt condition, proved it to be a valuable potash fertilizer. It 

 readily decomposes in most soils. 



LIME. 



Lime should be classed as a soil-stimulant rather than a fertilizer, for there are 

 few soils that do not contain sufficient lime to supply the needs of a crop as a plant- 

 food. The action of lime is usually not so immediate as that of a true fertilizer. It 

 is only when soil needs lime badly and where a liberal application is given that the 

 effect may be immediate and striking. The immediate effect of liming is more 

 frequently seen in the case of alfalfa and clover fields than with other crops. 



Although a plant-food, the primary purpose of liming is to neutralize soil- 

 acidity. Certain crops require more lime than they are able to secure from a soil 

 which is acid. But perhaps the most important benefit of lime is that by neutralizing 

 the soil-acidity it stimulates favourable forms of soil organisms that increase the 

 crop-producing power of soils. 



Lime improves the texture of clay soils, an important consideration in their 

 management. 



Burnt lime, and to a lesser degree ground limestone rock, has an effect of 

 increasing the available supply of plant : food, particularly potash in soils. 



