1016 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



acre, was 52 sieves of Sprouts, worth, at the market price of Is. 6d. per 

 sieve, £3 18s. ; while the cost of the extra 25 loads of dung was no less 

 than £5. An annual average increase of 65 sieves, worth £4 17s. per 

 acre, has, however, been obtained by substituting for the extra dung a 

 dressing of chemical fertilisers consisting of phosphates, potash salts, and 

 2 cwt. of nitrate of soda per acre, costing £2 5s. per acre. We thus 

 obtained, on the average of eight years, about £1 worth more produce per 

 acre, and at the same time saved £2 15s. per acre in manure, making a 

 total average saving of about £3 15s. per acre. In some individual years 

 it has been much more. 



So much for the economy of using a mixture of a light dressing of 

 dung with a dressing of chemical fertilisers, as against the more usual 

 plan of giving a heavy dressing of dung. But we have now to consider 

 the average results that are obtained on other plots on which no dung at 

 all has been used, as compared with the results obtained on the plots 

 receiving a heavy dressing of dung. The figures necessary for this 

 comparison are given in the following table : — 



BRUSSELS SPROUTS. 



Annual manuring per acre 



Annual cost of 

 manure per acre 



Five years' 

 average, 

 1894-1898 



Three years' 

 average. 

 1899-1901 





£ t. d. 



Sieves per acre 



Sieves per acre 



25 loads (12^ tons') London Dung . 



5 0 0 



244 



200 



50 loads (25 tons) London Dung . 



10 0 0 



279 



274 



Phosphates (no Potash) and 









4 cwt. Nitrate of Soda 



2 15 0 



260 





Ditto, ditto (with Potash) 



3 5 0 



292 





Phosphates (no Potash) and 









8 cwt. Nitrate of Soda 



4 15 0 





275 



Ditto, ditto (with Potash) 



5 5 0 





268 



In the case of the five years' average, the mean of the two chemically 

 fertilised plots shows a yield of 276 sieves per acre, as against 279 sieves 

 grown with the heavy dressing of dung alone. There was thus practically 

 no difference in the yield. But the cost of the heavy dressing of dung 

 was £10 per acre per annum, while that of the chemical fertilisers was 

 only £3, an average annual saving being thus effected of at least £7 per 

 acre by the total substitution of chemical fertilisers for dung. 



In the three following years the mean of the two chemically fertilised 

 plots shows a yield of 271 sieves per acre, that is to say, nearly the same 

 as the heavily dunged plot. The average cost of the chemical dressings 

 was in this case £5 per acre, while the heavy dressing of dung cost £10, 

 so that we have in the three years an average advantage of £5 per acre in 

 favour of the chemical fertilisers. 



While, on the whole, our experiments point to the general desirability, 

 in market gardening, of moderate dunging, supplemented by chemical 

 fertilisers, Brussels Sprouts appear to be a crop to which it is extravagant 

 to apply dung directly at all. The undunged plots in various parts of our 

 field, on which we have obtained such excellent results with chemical 

 manures alone in the case of Brussels Sprouts, are, it is to be remembered, 



