SOILS. 



145 



Estimates of the Yield and Gain of Carbon, and of the Increased Pi 

 per acre per annum, in various Crops, grown at Rothamsted, 



oduce of Carbohydrates, 

 Hertfordshire. 





Carbon. 



Carbohydrates. 



Actual. 



Gain. 



Gain. 



For 1 lb. 



Nitrogen 



in Manure. 



Wheat, twenty years, 1852-71. 



Mineral manure, 



Do. and 43 lbs. nitrogen as ammonia, ... 

 Do. and 86 lbs. nitrogen as ammonia, ... 

 Do. and 86 lbs. nitrogen as nitrate, 



lbs. 

 988 

 1590 

 2222 

 2500 



lbs. 



602 

 1234 

 1512 



lbs. 



1240 

 2550 

 3140 



lbs. 



28-8 

 297 

 36-5 



Barley, twenty years, 1852-71. 



Mineral manure, 



Do. and 43 lbs. nitrogen as ammonia, ... 



1138 



2088 



950 



1992 



46-3 



Sugar-beet, three years, 1871-73. 



Mineral manure, 



Do. and 86 lbs. nitrogen as ammonia, ... 

 Do. and 86 lbs. nitrogen as nitrate, 



1123 

 2600 

 3031 



1477 

 1908 



3188 

 4052 



37'1 



47-1 



Mangel-wurzel, eight years, 1876-83. 



Mineral manure, 



Do. and 86 lbs. nitrogen as ammonia, . . . 

 Do. and 86 lbs. nitrogen as nitrate, 



759 

 1889 

 2129 



1130 

 1370 



2376 

 2771 



27-6 

 32-2 



Potatoes, ten years, 1876-85. 



Mineral manure, 



Do. and 86 lbs. nitrogen as ammonia, ... 

 Do. and 86 lbs. nitrogen as nitrate, 



1021 



1783 

 1752 



762 

 731 



1507 

 1416 



17-5 

 16-5 



Beans, eight years, 1862 and 1864-70. 



Mineral manure, 



Do. and 86 lbs. nitrogen as nitrate, 



726 

 992 



266 



474 



5-5 



In Potatoes, reckoned on the increased pro- 

 duction of tubers only, the increased yield of 

 carbon by 86 lbs. of nitrogen as ammonium 

 salts was 762 lbs. per acre, and by 86 lbs. as 

 sodium nitrate, 731 lbs. That is to say, there 

 was considerably less increased production of 

 starch in Potatoes than of sugar in Sugar-beet 

 or Mangel-wurzel by the same applications of 

 nitrogenous manure. 



Lastly, in the Leguminous crop — Beans, with 

 its high yield of nitrogen per acre, and the high 

 percentage of nitrogen in its dry substance — 

 the increased assimilation of carbon under the 

 influence of nitrogenous manure was, compara- 

 tively, quite insignificant. Thus, there was, by 

 the application of 86 lbs. of nitrogen as sodium 

 nitrate, an increased assimilation of carbon of 

 only 266 lbs. per acre, or little more than one- 

 sixth as much as in Wheat, and little more than 

 one-eighth as much as in Sugar-beet, by the 

 same application. 



Turning to the figures in the third column 

 of the foregoing table, it is seen that there was 

 vol. L 



a very greatly increased production of the non- 

 nitrogenous bodies — the carbohydrates — by the 

 use of nitrogenous manures. Thus, by the 

 use of 43 lbs. of nitrogen as ammonium salts, 

 there was an estimated increase of 1240 lbs. 

 of carbohydrates in the grain and straw of 

 Wheat, and of 1992 lbs. in those of Barley. 

 By the application of 86 lbs. of nitrogen as 

 ammonium salts there was an increased forma- 

 tion of 2550 lbs. of carbohydrates in Wheat, of 

 3188 lbs. in Sugar-beet, of 2376 lbs. in Mangel- 

 wurzel, and of only 1507 lbs. in Potatoes; and 

 when 86 lbs. were applied as sodium nitrate 

 there was an increased production of 3140 lbs. 

 in Wheat, of 4052 lbs. in Sugar-beet, of 2771 

 lbs. in Mangel-wurzel, and of only 1416 lbs. in 

 Potatoes; whilst, compared with these amounts, 

 there was in Beans, by the same application, an 

 increase of only 474 lbs. of carbohydrates. 



The last column shows the increased amounts 

 of carbohydrates produced for 1 lb. of nitrogen 

 supplied in manure in the different cases. Thus, 

 when 43 lbs. of nitrogen were applied as am- 



10 



