38 THE ROTIIAMSTED EXPERIMENTS. 



should find an increased amount of potash taken up. In 

 fact, the lower division of the table shows that, with the 

 same potash supply by manure, there was, compared with 

 the amount stored in the root without nitrogenous supply, 

 more than three times as much where nitrate of soda was 

 added, nearly three times as much where ammonium-salts 

 were used, about three times as much where rape-cake was 

 employed, and nearly four and a-half times as much where 

 rape-cake and ammonium-salts were applied together, supply- 

 ing an excessive amount of nitrogen. The actual amounts of 

 potash per acre in the roots were indeed — only 35.6 lb. per 

 acre per annum without nitrogenous supply, 117.1 lb. with 

 nitrate of soda, 104.4 lb. with ammonium-salts, 113.9 lb. with 

 rape-cake, and 155.1 lb. with the excessive supply of nitrogen 

 in ammonium-salts and rape-cake together. 



Although, as has been seen, the percentage of potash was 

 very much higher in the dry substance of the sugar-beet leaf 

 than in that of the root, the figures in the lower division of 

 the table show that under all conditions as to nitrogenous 

 supply there was much less potash per acre in the leaf than 

 in the root. As, however, the leaf would be returned to the 

 land as manure, there should be no loss of the potash of the 

 farm by the amount of it left in the leaf. And again, as the 

 very much larger amount of potash in the roots should, when 

 consumed on the farm, be almost wholly recovered in the 

 manure of the animals fed upon them, there should be but 

 little loss to the farm of the potash they contained. If, how- 

 ever, either the roots or the leaves are removed or sold off 

 the farm, the exhaustion of potash may be very considerable. 

 Phosphoric Turning to the amounts of phosphoric acid, the supply of 

 Tndleaf 00t which was the same for each of the five series, it has been 

 seen that the percentage of it in the dry substance of the 

 roots varied comparatively little ; but the figures in the lower 

 division of the table show that the actual quantities per acre 

 in the roots varied very considerably, and to a great extent 

 in proportion to the amounts of growth as influenced by the 

 nitrogenous supply. It is further seen that the amounts of 

 phosphoric acid remaining in the leaf are very small com- 

 pared with those in the root. 

 Produce It has already been shown when considering the results 



mZuttf recorded in Table 9 (p. 33) relating to the selected artificially- 

 and resi- manured plots, that the produce over the two years after the 

 due-action. cessa t;i on f the application of the nitrogenous manures in- 

 dicated considerable increase over that where no nitrogen 

 had been applied, due partly to the residue of the nitrogenous 

 manures previously applied, and partly to the residue (leaves, 

 &c.) of the larger crops previously grown. It will be of in- 

 terest here to show the average produce of roots per acre per 



