362 ORGANIC ELEMENTS 1 MANl RES AND CROPS. 



WHEAT STUBBLE. 



From 120 square yards of ground we have obtained 13 lbs. of 

 Btubble dried in the air. The same surface in another field produced 

 171 lbs. 



Thus we have 5| cwts. of stubble per acre ; but as wheat recurs 

 twice in the rotation, the residues must be doubled ; say, IH cwts. 

 Stubble loses 0,26 of moisture when dried completely at 230°. 



In 1839, the wheat after the drilled crop, or after clover, was only 

 17 bushels per acre. 



I have assigned to stubble the same composition as that of straw. 



CLOVER ROOTS. 



A surface of 120 square yards gave 44 lbs. of roots, weighed after 

 being thoroughly dried in the sun ; when pulverized after drying in 

 the stove the weight was reduced to 37 lbs. 



3 oz. 4 dwts. of powdered roots lost by drying, at a temperature 

 of 230° F., 5 dwts. of moisture. Thus the U lbs. of roots dried in 

 the sun would have weighed 34 lbs., and one acre would have 

 furnished 12^ cwts. of residue perfectly dry. 



In 1839, the clover crop when reduced to hay was far below the 

 average. 



COMPOSITION OF THE ROOTS. 



Carbon 434 



Hydrogen 5.3 



Oxygen t 36.9 



Azote 1-8 



Salts and earth -.-Ig.ti 



100.0 

 OAT STUBBLE. 



The residue of the oat crop, whichconcludes the rotation course, 

 does not act upon the present, but on the next rotation ; in the same 

 way as the organic remains left in the ground by the oats which ter- 

 minatfd the antecedent course, e.xerted their influence upon the 

 present one. In 1839, the oat crop was above the average ; it wa« 

 as high as 16 cwts. 2 qrs. 18 lbs. per acre. 



One French are of the land, equal to 120 square yards English, 

 yielded 20 lbs. of stubble dried in the air, or at the rate in round 

 numbers of 8 cwts. per acre. 



In the following table 1 have given a s- mmary of the results above 

 stated, combining therewith the quantity ind the composition of the 

 manure expended in the rotation. 



