ROOT-CROPS. 37 



will be seen further on how large a proportion of the solid 

 matter of the root of this highly artificial vegetable produce 

 is sugar. 



The lower division of the table further shows that, whilst 

 there was only 14.3 lb. of nitrogen per acre in the roots with- 

 out nitrogenous supply, the amount was raised — by nitrate of 

 soda to 67 lb., by ammonium-salts to 51.2 lb., by rape-cake 

 to 58.4 lb., and by rape-cake and ammonium-salts together to 

 105.5 lb. Then the amount of nitrogen per acre in the leaf 

 was — with mineral but without nitrogenous manure 9.5 lb., 

 with the addition of nitrate of soda 32.8 lb., of ammonium- 

 salts 21.5 lb., of rape-cake 21.6 lb., and of rape-cake and 

 ammonium-salts together 48.8 lb. A point of interest 

 in regard to the amounts of nitrogen per acre in the crops is, 

 however, that there was in every case very much more 

 accumulated in the root than in the leaf, which is chiefly of 

 value only as manure again. 



It is further seen that with the same mineral, but 

 varying nitrogenous supply, the amount of total mineral 

 matter per acre in the roots was — only 101.2 lb. without 

 nitrogen supply, 364.2 lb. with nitrate of soda, 288.5 lb. with 

 ammonium-salts, 322.1 lb. with rape-cake, and 469.6 lb., or 

 more than 4 cwt., with the rape-cake and ammonium-salts to- 

 gether. Lastly, the total amount of mineral matter per acre 

 in the leaf was, with the very high percentage in the dry 

 substance, very large ; but it was in each case, with nitro- 

 genous supply, considerably less in the leaf than in the root. 

 It is remarkable that with the same mineral supply in each 

 case there was, without nitrogen, less than 2 cwt. of mineral 

 matter per acre per annum in root and leaf together, whilst 

 with the highest nitrogenous supply in addition there was 

 nearly 7f cwt. of mineral matter in the total crop. There 

 is here evidence both of how liberal must be the supply of 

 available mineral constituents for the luxuriant growth of 

 the crop, and how great will be the exhaustion of them if 

 the crop be sold off the farm. 



Bearing in mind that the same amount of potash was applied Nitrogen 

 per acre in the case of each of the five series, it is of interest and^i^r- 

 to observe that the percentage of potash in the dry substance production. 

 of the root was distinctly higher in the four series with 

 nitrogenous supply than in Series 1 without it ; and when 

 we consider, as will be fully illustrated further on, that the 

 amount of sugar produced depends very materially on the 

 amount of nitrogen taken up, and that a liberal supply of 

 available potash has also much influence on the amount of 

 sugar produced, it is what might be expected that, with 

 liberal nitrogen-supply and increased production of sugar, we 



