igo6.] 



Potato Growing. 



23 



of the latter along with dung caution is necessary ; it is 

 believed that artificials are frequently applied in excess of the 

 requirements of the crop, and that, in consequence, smaller 

 profits are obtained than when more economical methods are 

 followed. 



When crops of from 9 to 10 tons per acre can be grown 

 solely by the aid of moderate dressings of dung there is a risk 

 that any increase in yield obtained by the use of artificials in 

 addition may be produced at too great a cost. 



The following mixture of artificials per acre may be recom- 

 mended as a safe and reliable one under most circumstances, 

 and no farmer should use artificials in greater quantity along 

 with 10 tons of dung until he has thoroughly satisfied himself 

 that it can be done with profit : — 



1 cwt. sulphate of ammonia. 



2 cwt. superphosphate. 



I cwt. sulphate of potash. 



Sulphate of Ammonia v. Nitrate of Soda. — When used along 

 with dung there is generally little to choose between these two 

 sources of nitrogen, but when no dung is used the results are 

 mostly in favour of sulphate of ammonia. 



Diffej^ent Potash Manures. — Sulphate of potash, in most cases, 

 will give the best results, but there is so little to choose between 

 the sulphate and the muriate that a farmer in purchasing should 

 be guided by their respective unit prices. 



Both these forms have proved superior to kainit. There is 

 an idea prevalent amongst farmers that kainit, owing to its 

 attractive power for moisture, is superior to the other forms 

 on sandy or light soils, especially in a dry season. This, 

 however, has not been borne out by the Yorkshire experi- 

 ments. 



Rape meal, as a manure for potatoes, is held in high favour in 

 districts where the soils are of a light character. It contains 

 about 5 per cent, of nitrogen and 3 per cent, of phosphate, and, 

 like most organic manures, decomposes slowly in the soil. In 

 experiments conducted in 1905, 2 cwt. per acre, applied along 

 with \ cwt. sulphate of ammonia, i cwt. sulphate of potash, and 

 10 tons dung, gave very satisfactory results on light soils in 

 Yorkshire. 



