82 THE POTATO. 



apply the farmyard manure in the drills, just before plant- 

 ing. Experiments, as a rule, have shown that nothing 

 beats a very heavy dressing of natural manure, and in 

 many cases the addition of artificials to twenty tons or 

 more of dung has had comparatively little effect, and has 

 riot proved remunerative. On the other hand, ten tons 

 of dung and a dressing of artificial manures have usually 

 given as good results as double the quantity of the former 

 alone, and sometimes better crops. In all cases, the arti- 

 ficials should contain nitrogen, phosphoric acid, and 

 potash. A dressing that has almost invariably given great 

 satisfaction consists of 10 tons of dung, 4 cwt. of super- 

 phosphate, 1 to 2 cwt. of sulphate or muriate of ammonia, 

 and 1 to 2 cwt. of sulphate of potash. When no dung is 

 available, a successful dressing is made up of 4 cwt. of 

 superphosphate and 2 cwt. each 'of sulphate of ammonia 

 and sulphate of potash, applied at planting time, and fol- 

 lowed, just before the potatoes are earthed up, with 1 cwt. 

 per acre of nitrate of soda as a top dressing. In some 

 cases, such liberal artificial manuring has given crops as 

 good as where dung has been used, and at a smaller cost 

 when town dung has been purchased. As a source of 

 potash sulphate has done best in some cases, and muriate 

 in others, each having almost invariably beaten an equiva- 

 lent quantity of kainit. When nitrate of soda is used 

 instead of sulphate of ammonia, partly at the time of 

 planting, and partly later, it should not be mixed with the 

 supersphosphate, unless the mixture is certain to be sup- 

 plied on the same day, because chemical action takes 

 place hi such a mixture, causing loss of nitrogen. But 

 sulphate or muriate of ammonia may be mixed with super- 

 phosphate at any time. The potash may be mixed with 

 any of the other manures. See also the chapter on 

 Manures. 



Planting 1 . Very early crops are commonly planted in 

 February, or occasionally, in Jersey, Cornwall, and the 

 Scilly Isles, in the latter part of January, if the laD'l be 



