^fj^ BOAKD OF AGRICULTURE. 



may be briefly described as a stiff clay-soil, containing a sufficiency 

 of lime, potash, and phosphoric acid to meet all the requirements 

 of the clover crop. Originally rather unproductive, it has been 

 much improved by deep culture ; by being smashed up into rough 

 clods early in autumn, and by being exposed in this state to the 

 crumbling effects of the air, it now yields good corn and forage 

 crops. 



In separate portions of the three layers of soil, the proportions 

 of nitrogen and phosphoric acid contained in each layer of six 

 inches were determined and found to be as follows : 



Soil dried at 212= Fahr. 

 1st, 6 inches. 2d, 6 inches. 3d, 6 inches. 



Percentage of phosphoric acid 249 134 172 



Nitrogen 1G2 092 064. 



Equal to ammonia 198 112 078 



In the upper six inches, as will be seen, the percentage of both 

 phosphoric acid and nitrogen was larger than in the two following 

 . layers ; while the proportion of nitrogen in the six inches of sur- 

 face soil was much larger than in the next six inches ; and in the 

 third section, containing no visible particles of root-fibres, only 

 very little nitrogen occurred. 



In their natural state the three layers of soil contained — 



1st, 6 inches. 2d, 6 inches. 3d, 6 inches. 



Moisture 17.16 18.24 16.C2 



Phosphoric acid 198 109 143 



Nitrogen 134 075 053 



Equal to ammonia 162 091 06-4 



lbs. lbs. lbs. 



Weight of 1 foot square of soil 60 61 63 



Calculated per acre, the absolute weight of 1 acre of this land, 

 6 inches deep, weighs : 



lbs. 



Ist, 6 inches 2,613,600 



2d, " 2,657,160 



3d, " 2,746,280 



No great error, therefore, will be made if we assume in the 

 subsequent calculations that 6 inches of this soil weigli 2| millions 

 of pounds per acre. 



An acre of land, according to the preceding determinations, 

 contains : 



Ist, 6 inches, 2d, 6 inches. 3d, 6 inches, 

 lbs. lbs. lbs. 



Phosphoric acid 4,950 2,725 3,575 



Nitrogen 3,350 1,875 1,325 



Equal to ammonia 4,050 2,276 1,600 



