LOSSES DURING ROTATION. 



71 



in the course of the rotation, and the rest used as litter. 

 If the whole of the manure is returned without loss to 

 the land, the quantities of nitrogen, phosphoric acid, and 

 potash lost during the four years' rotation, as excess 

 of exports over imports, will be as follows : 



ESTIMATED LOSSES PER ACRE DURING A FOUR-COURSE 

 ROTATION BY SALE OF CORN AND MEAT.* 



The loss of potash is extremely small, and may gener- 

 ally be quite disregarded. If, however, no cake is used, 

 and the land is poor in potash, the loss might be replaced 

 by the use of ] i cwt. of kainite for the seeds. The loss 

 of potash will be greater than we have assumed if urine 

 has been lost in the stables, or if the farmyard manure 

 has suffered by rain and drainage. 



The loss of phosphoric acid would be replaced, even 



* The figures given in this table differ from those in former editions, 

 more complete data being now available. It is now assumed that 

 the crops are consumed by sheep and cattle of all ages, and not 

 simply by fattening stock. 



