1038 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Bonum ' ; in 1896, ' Imperator ' ; in 1897 and 1898, ' Magnum Bonum ' ; 

 and in 1899, 1900, and 1901, ' Up-to-date.' 



The results of our experience over the fifteen crops are summarised in 

 the following table : — 



POTATOS. 







Average annual yield of 

 Potatos per acre 



Annual manuring per acre 



Annual cost 







of manure 







per acre 



Early varieties 



Late varieties 





(seven years' 

 average) 



(eight years' 

 average) 





£ s. d. 



tons cwt. 



tons cwt. 



50 loads (25 tons) London Dung . 

 25 loads (12^ tons) London Dung 



10 0 0 



7 7 



10 6 



5 0 0 



5 14 



8 15 



25 loads Dung, Phosphates (no Potash), and 









2 cwt. Nitrate of Soda .... 



6 15 0 



G 4 



9 13 



Ditto, ditto (with Potash) .... 



7 5 0 



6 9 



10 9 



25 loads Dung, Phosphates (no Potash), and 









4 cwt. Nitrate of Soda .... 



7 15 0 



6 7 



10 5 



Ditto, ditto (with Potash) .... 



8 5 0 



6 10 



11 3 



* No Dung ; Phosphates (no Potash) and 









4 cwt. Nitrate of Soda .... 



3 5 0 



3 6 



5 8 



Ditto, ditto (with Potash) .... 



3 15 0 



4 10 



8 0 



* 8 cwt. Nitrate in 1900 and 1901. 



As far as early varieties are concerned, the best results have been 

 obtained with a very heavy dressing of dung. This has been the case 

 not only on the average, but in every one of the seven seasons. This 

 experience, having regard to our results with other vegetables, is excep- 

 tional, and is no doubt to be attributed to the extra dung keeping the soil 

 moist in the series of years in which the summers have on the average 

 been exceptionally dry, the growth of early Potatos being entirely con- 

 fined to the period of summer. 



Having regard, however, to the cost of the extra dung — namely, 4s. 

 per load or 8s. per ton — it would seem that the smaller crop grown with 

 the aid of a moderate dressing of dung accompanied by a mixture of phos- 

 phates, potash salts, and 2 cwt. of nitrate of soda per acre, has been on 

 the average not much less economical. Nevertheless in some years the 

 advantage, even from an economical point of view, has been decidedly 

 with the heavy dung, for early Potatos ; and, as the value of this crop 

 very often depends upon its earliness, this seems to be a case in which 

 the extravagance of heavy dunging is on the whole probably justified, at 

 all events on such stiff or heavy soils as we have at Hadlow. 



When, however, we come to the late or main-crop Potatos, no advan- 

 tage seems to lie with heavy dunging ; for the average crop produced by 

 50 loads of dung per acre over eight years is no greater than that pro- 

 duced at a considerably less cost by a light dressing of dung in conjunc- 

 tion with a dressing of phosphates, potash salts, and 2 cwt. of nitrate of 

 soda per acre. The addition of 2 cwt. more of nitrate per acre, making 

 4 cwt. in all, has still further increased the average yield of Potatos, and 

 has increased in considerably greater ratio than the extra cost of manure. 



Potash has throughout increased the crop, but the increase due to it 

 on the dunged plots has been much less in the case of early Potatos than 



