EXPERIMENTS ON CLOVER-SOILS. 153 



" Accordingly the clover-roots in an acre of land furnished 24^ 

 Ibs. of nitrogen. We have thus : 



Lbs. of 

 nitrogen. 



In the six inches of surface soil 3,350^ 



In large clover-roots 



In second six inches of soil 1,<5 



Total amount of nitrogen in one acre of soil 12 inches deep 5,249 



Equal to ammonia ^?I^t 



Or in round numbers, two tons six cwt. of nitrogen per acre ; an 

 enormous quantity, which must have a powerful influence in en- 

 couraging the luxuriant development of the succeeding wheat- 

 crop, although only a fraction of the total amount of nitrogen in 

 the clover remains may become sufficiently decomposed in time to 

 be available to the young wheat-plants. 



CLOVER-SOIL FROM PART OF 11-ACRE FIELD OF BURCOTT 



LODGE FARM, LEIGHTON BUZZARD, ONCE MOWN 



FOR HAT, AND LEFT AFTERWARDS FOR SEED. 



" Produce 2| tons of clover-hay, and 3 cwt. of seed per acre. 



" This soil was obtained within a distance of five yards from the 

 part of the field where the soil was dug up after the two cuttings 

 of hay. After the seed there was some difficulty in finding a 

 square foot containing the same number of large clover-roots, as 

 that on the field twice mown ; however, at last, in the beginning of 

 November, a square foot containing exactly 18 strong roots, was 

 found and dug up to a depth of 18 inches. The soil dug after the 

 seed was much drier than that dug after the two cuttings of hay : 



The upper six inches deep, one foot square, weighed 55 Ibs. 



The next " u t? 58 " 



The third " " " .. 60 " 



" After drying by exposure to hot air, the three layers of soil 

 weighed : 



The upper six inches, one foot square 40t Ibs. 



The next " " 5<H " 



The third " " 5H " 



"Equal portions of the dried soil from each six-inch section 

 were mixed together and reduced to a fine powder. An average 

 sample thus prepared, on analysis, was found to have the follow- 

 ing composition : 



