1026 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



last three years, in which we have used extended dressings of nitrate of 

 soda on some of the plots : — 



CARROTS. 



Annual manuring per acre 



Annual cost 

 of manure 

 per acre 



Annual weight of Carrots 

 per acre 



Average of t ^!S S oL 

 sxx seasons ~TSB5 





£ 



s. 



d. 



tons cwt. 



tons 



cwt. 



50 loads (25 tons) London Dung (applied to 



















nil 





15 2 



15 



10 



25 loads (12| tons) London Dung (applied to 



















nil 





12 15 ; 



12 



6 



25 loads Dung (to previous crop) ; Carrots dressed 















with Phosphates (without Potash) and 















2 cwt. Nitrate of Soda 



1 



15 



0 



13 8 



10 



13 



Ditto, ditto (with Potash) : 



2 



5 



0 



15 14 



13 



2 



25 loads Dung (to previous crop) ; Carrots dressed 















with Phosphates (without Potash) and 















4 cwt. Nitrate of Soda 



2 



15 



0 



14 11 



12 



7 



Ditto, ditto (with Potash) ..... 



3 



5 



0 



16 2 



14 



11 



25 loads Dung (to previous crop) ; Carrots dressed 















with Phosphates (without Potash) and 















6 cwt. Nitrate of Soda . . . . . 1 



3 



15 



0 





11 



17 



Ditto, ditto (with Potash) 



4 



5 



0 





14 



10 



It appears that, on the average, the residue of even a heavy dunging 

 of 50 loads per acre applied to the previous crop has been insufficient to 

 grow a full crop of Carrots, while the residue of a smaller dressing of 

 dung has been still less effective. The application to the Carrots of 

 chemical fertilisers, consisting of phosphates, potash salts, and 2 cwt. of 

 nitrate of soda per acre, has resulted in a gain, over six years, of nearly 

 3 tons of Carrots per acre per annum, while the addition of 2 cwt. 

 more of nitrate per acre has further raised the increase. During some 

 years the dressing of nitrate has given a much more substantial advantage. 

 The further increase of the nitrate to 6 cwt. per acre has not increased 

 the crop. 



The effect of potash on Carrots throughout our experiments has been 

 remarkable, even on the plots to which 25 loads of dung per acre 

 have been applied nearly every previous year during our experimental 

 period. Thus, in looking at the five years' averages, we find that, in 

 round numbers, the use of potash on the plots receiving phosphates and 

 2 cwt. of nitrate of soda per acre (although dung had been applied in 

 most other years for some crop or other) has resulted in an average 

 increase of nearly 2] tons of Carrots per acre. During the last three 

 years, in which the land has presumably become more potash-exhausted 

 than in the earlier years, we find that, on the three dunged plots, potash 

 produced a much larger increase. There is no reason, however, for sup- 

 posing that potash salts alone would have given anything like this increase 

 in the crops. This must be attributed to the action of the phosphatic 

 manure and of the nitrate of soda as well as to that of the potash. The 

 point, however, is that phosphates and nitrate of soda, even when applied 

 in the most liberal abundance, have shown themselves,in the absence of 



