ROOT-CHOPS. 55 



The percentage of total mineral matter is on the average 

 about three times as high in the dry substance of the leaf as 

 in that of the root. It is, however, higher in the dry sub- 

 stance of the root, and lower in that of the leaf, than in the 

 case of the sugar-beet. Further, the table shows that, ex- 

 cepting in the case of Series 2 with nitrate of soda, and much 

 soda in the ash, there was a higher percentage of potash in 

 the dry substance of the leaf than in that of the root ; but 

 about the same percentage of phosphoric acid in the dry 

 substance of the leaf as in that of the root. It is to be 

 observed, however, that the percentage of potash in the dry 

 matter of the mangel root is much higher than in that of the 

 sugar-beet root, in which so much more sugar, and with it so 

 much more dry substance, is produced. On the other hand, 

 the percentage of potash in the dry substance of the mangel 

 leaf is generally distinctly lower than in the case of the 

 sugar-beet. 



Upon the whole, the percentage results show the higher Ripeness 

 percentage of dry matter and the lower percentage of a ^^' f 

 nitrogen in the dry matter in both root and leaf the riper root and 

 the crop ; also the lower percentage of total mineral matter lea <f- 

 in the dry substance of the root the riper the crop ; and con- 

 versely, there is a lower percentage of dry matter and a 

 higher percentage of both nitrogen and mineral matter in 

 the dry substance the more luxuriant and less ripe the crop. 



The lower division of the Table (16) shows that whilst 

 • there was only about two- thirds of a ton of dry substance 

 per acre in the root (that is, in the food-product of the 

 crop) without nitrogenous manure, there were nearly 3 tons 

 with the highest nitrogenous manure ; and there was, besides, 

 about five times as much dry substance per acre in the leaf 

 of the larger as in that of the smaller crop. There is here, 

 . again, a striking illustration of the dependence of the amount 

 of carbon assimilated from the atmosphere over a given area 

 on the amount of nitrogen available to the plant within the 

 soil. The quantity of dry substance produced per acre under 

 the influence of the highest nitrogenous manuring would 

 contain considerably more than 1 ton of carbon ; indeed the 

 increased amount of carbon assimilated under the influence 

 of the nitrogenous manuring would be not much less than 

 1 ton per acre. 



The table further shows that with the highest nitrogenous 

 manuring, the greatest luxuriance, and the lowest maturation 

 of the crop, there was more than six times as much solid 

 matter accumulated in the food-product, the root, as in the 

 leaf ; whilst in the other cases, with smaller crops and better 

 maturation, there was from seven to eight times as much 



