1032 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Considering first the seven years' average, it will be seen that the 

 doubling of the dung from 25 loads to 50 loads per acre resulted in an 

 average increase of less than a ton per acre. When the additional dung- 

 was replaced by chemical fertilisers, however, including 2 cwt. of nitrate 

 of soda per acre, the increase averaged 2 tons per acre ; while, with the 

 further increase of nitrate of soda to 4 cwt. per acre, the increase of 

 Spinach per acre was over 2} tons. 



If we look at the average of the later years, when the seasons were 

 more favourable to the growth of Spinach and the crops were consequently 

 larger, we find even more striking results. While the 25 additional loads 

 of dung raised the yield by about H ton per acre, this increase was 

 doubled by using, in place of the additional dung, chemical fertilisers 

 including only 2 cwt. of nitrate of soda per acre. Where 4 cwt. of nitrate 

 was applied, the average increase is over 3^ tons per acre ; while with a 

 further increase of the dressing of nitrate to 6 cwt. per acre we get an 

 increase in crop of about 4| tons per acre, as compared with about H ton 

 obtained by the use of the extra dung. 



Even on the plots on which no dung at all was used, but on which 

 the dung was replaced entirely by chemical fertilisers consisting of 

 phosphates, potash salts, and 8 cwt. of nitrate of soda per acre, the crop 

 grown was twice as large as that grown with 25 loads of dung per acre 

 without chemical fertilisers, although the chemical fertilisers cost only a 

 few shillings per acre more than the dung which they replaced. 



WINTER SPINACH. 

 Grown in 1898 and 1901 after the crops of Summer Spinach were removed. 



Manure applied per acre each year to previous crop 

 Summer Spinach 



50 loads (25 tons) London Dung 

 25 loads (12$ tons) London Dung . 

 25 loads Dung, Phosphates (no Potash), 



1 cwt. Nitrate of Soda . 

 Ditto, ditto (with Potash) 



25 loads Dung, Phosphates (no Potash), 



2 cwt. Nitrate of Soda . 

 Ditto, ditto (with Potash) 



25 loads Dung, Phosphates (no Potash), 



4 cwt. Nitrate of Soda . 

 Ditto, ditto (with Potash) 

 25 loads Dung, Phosphates (no Potash), 



6 cwt. Nitrate of Soda . 

 Ditto, ditto (with Potash) 

 No Dung; Phosphates (no Potash) and 



Soda 



Ditto, ditto (with Potash) 



No Dung ; Phosphates (no Potash) and 



Soda 



Ditto, ditto (with Potash) 



md 



and 



Dd 



and 



cwt 



cwt 



Nitrate of 



Nitrate of 



Yield of Winter Spinach 

 per acre 



1898 



tons 



17 

 10 



18 

 10 



17 

 17 



22 

 21 



cwt. 



19 

 0 



9 



12 



3 

 0 



10 

 12 



tons cwt. 

 7 5 

 4 10 



7 

 Id 



3 12 

 10 11 



The use of potash for Summer Spinach has proved decidedly advan- 

 tageous on the plots on which no dung was used, and in numerous 

 instances during our experience it has also appeared to be useful even on 

 the plots manured with a moderate dressing of dung, although in many 



