158 Commercial Gardening 



basic slag over the compost heap will produce excellent results in the way 

 of early bloom, &c. 



Wood Ashes, &C. Besides bones, superphosphate, and basic slag, other 

 manures are also valuable for the amount of phosphates they contain. 

 Wood ashes, i.e. the burnt refuse from weeds and plants of all sorts, con- 

 tain from 100 to 145 Ib. of phosphates in every ton, and even a larger 

 supply of potash 135 to 224 Ib. in every ton. 



Guanos both Peruvian and fish also contain large quantities of phos- 

 phates, Peruvian guano having from 350 to 400 Ib. in every ton, and fish 

 guano from 200 to 300 Ib. Farmyard and stable manure, seaweed, sewage 

 sludge, soot, night soil, pigeon, poultry, and all animal excreta contain 

 supplies of phosphates as well as nitrates and potash. 



Limphos. This name has been given to a new fertilizer, said to contain 

 40 per cent of phosphates and 35 per cent of lime. It is probably a com- 

 mercial name for a form of superphosphate, and is no doubt similar in 

 action. 



6. POTASH MANURES 



It must be a very poor soil indeed which does not contain large supplies 

 of potash. This is locked up with other elements, but fair quantities may 

 be liberated annually by cultivation and the application of organic manures. 

 A fertile soil has been computed to contain about 30,000 Ib. of potash to 

 the acre at 9 in. deep, while a soil at Rothamsted which had not been 

 manured for fifty years contained 6750 Ib. of potash to the acre at 9 in. 

 deep. The quantity of available potash needed for certain crops varies 

 from 36 to 500 Ib. per acre, as may be seen by reference to the figures 

 on p. 144. 



Before referring to special artificial potash manures it may be remarked 

 that all organic manures, such as stable manure, the dung of all animals 

 and birds, soot, seaweed, and wood ashes, contain supplies of potash, 

 which are liberated when incorporated with the soil. 



Amongst the special potash manures are the following: 



Kainit. This is one of the most popular potash manures at present 

 in use. It is a crude natural salt obtained from Germany, and varies in 

 colour from creamy white to pale pink. Pure samples contain potassium 

 equal to nearly 19 per cent of potash. The usual commercial article only 

 contains about 12'4 per cent of potash. In bulk, commercial kainit con- 

 tains about 35 per cent of common salt, about 30 per cent of magnesium 

 salts (chiefly Epsom salts), and about 12*5 per cent of water of crystalliza- 

 tion. The remainder 22*5 per cent is almost entirely potassium salts. 

 It will thus be seen that less than one-fourth the bulk consists of the 

 important fertilizer potash. 



As a manure, kainit has the disadvantage of having such a large per- 

 centage (35) of common salt, but with such crops as Mangels and Asparagus 

 this is not a drawback, as those crops benefit by the addition of salt to the 



