Distribution of Nitrogen in the Soil. 



199 



nitrogen of the farmyard manure remains available within 

 the soil. 



In the autumn of 1865, after twenty-two years' continuous 

 growth of wheat, samples of the soils were taken from many 

 of the plots, in each case from the first 9in., the second 9in., 

 and the third 9in. in depth. Eather more than one and two- 

 thirds as much nitrogen was determined in the first 9in. of 

 the farmyard-manured as in the corresponding layer of the 

 unmanured plot, and about one and a half times as much as 

 to a corresponding depth of any of the plots receiving 

 artificial nitrogenous manures. Determinations made after 

 the farmyard manure had been applied some years longer 

 showed more than twice as much nitrogen in the first 9in. as 

 without manure. Table LII. is drawn out in the same form 

 as Table XL VIII., page 194. 



TABLE LII. EXPERIMENTAL WHEAT FIELD. ESTIMATED AMOUNT OF 

 DRY SOIL PER ACRE AT EACH DEPTH ; NITROGEN PER CENT. IN THE 

 DRY SOILS, AND ESTIMATED NITROGEN PER ACRE, AT EACH DEPTH. 



Furthermore, in the case of the wheat experiments, as shown 

 in Table LIIL, page 200, the loss of nitrogen by drainage or 

 otherwise is estimated to be about 40 per cent, of that 

 supplied ; in that of the hay plot reckoned to the same, or 

 27in., of depth (Table L., page 196), 25'2 per cent., or, to 

 the depth of 54in. (Table XLIX., page 195), 49 per cent. 



