18 THE STOCKFEEDER'S COMPANION 



there is a considerable drain on the store of nitrogen, 

 phosphates, and lime in the soil to supply the require- 

 ments of the animal body. Nitrogen maybe collected 

 from the air to a fairly considerable extent by the 

 roots of clovers and other leguminous plants in the 

 pasture, but this does not apply to minerals such as 

 phosphates and lime. This explains why grass-land 

 which has been grazed continuously with young cattle 

 is apt to become destitute of these two substances ; also 

 why basic slag, which supplies both phosphates and 

 lime, in many cases gives wonderful results when 

 applied to such pastures. It is generally wise to include 

 some kainit in the manurial mixture used on pastures, 

 in case there might also be a shortage of potash. 



In the same way, every store sheep of 100 Ibs. live 

 weight (which means a good big sheep) in building up 

 its body has removed an amount of minerals from 

 its food, and indirectly from the soil, equal to 

 14^ Ibs. nitrate of soda, 8J Ibs. superphosphate of lime 

 (30 per cent, soluble phosphate), J Ib. pure sulphate of 

 potash, and nearly if Ibs. of ground lime (80 per cent, 

 pure). If the sheep had been reared entirely on grass, 

 the pasture would have lost the above amounts of 

 minerals and nitrogen. 



The ox requires a larger amount of minerals in 

 proportion to its weight for its body requirements than 

 either the sheep or the pig ; and the pig requires less 

 in proportion to its size than the sheep. 



The large amounts of nitrogen and potash in 

 unwashed wool are both very striking. The latter 

 constituent, no doubt, finds its way into the fleece in the 

 perspiration, just in the same way as it does into the 

 coat of a horse. There must sometimes be fully half a 

 pound of potash in a sheep's fleece, 



