47 



after the removal of 151*9 Ibs. in clover, than after 

 the removal of only 37'3 Ibs. in barley. 



In October, 1873, after the removal of the barley and 

 the clover, samples of soil were taken from 10 places on 

 each of the two portions, in each case to the depth 

 of 3 times 9 inches, or 27 inches. Nitrogen was deter- 

 mined, by soda lime, in the samples from each depth, of 

 4 of the individual holes separately, and in the mix- 

 ture of the 4; also for each depth, in a mixture of 

 the samples from the other 6 places. In the first-depth 

 samples the carbon was also determined. 



The results showed that the surface soil of the clover 

 land, which had yielded so much more nitrogen in the 

 crops, was nevertheless determinably richer in nitrogen 

 than that of the barley land which had yielded so much 

 less. This was the case, notwithstanding all visible 

 vegetable debris had first been removed from the 

 samples. It was further found, that the above and 

 underground vegetable residue, picked from the clover- 

 land samples, was much more in quantity, and contained 

 much more nitrogen, than that from the barley-land 

 samples. 



In 1874 and 1875, barley only was sown over both 

 portions. In 1876 barley was again sown over the 

 whole of the land, but with clover as well on the por- 

 tions where it had been grown in 1873 ; but the plant 

 failed in the winter, and gave no crop in 1877. In 

 1877 barley was again sown over the whole, and this 

 time with clover on half of the previously clover 

 portion, and on half the previously only barley portion. 



In the autumn of 1877, soil samples were again taken, 

 this time from four places on each of the four differently 

 cropped portions, and in each case to the depth of 

 times 9 inches, or 54 inches. Nitrogen, by soda-lime, 

 has been determined in the mixture from the four holes 

 on each plot, for each depth separately. Nitric acid 

 has been determined, at each depth, in the mixture 

 from the four holes in the case of two of the four plots, 

 and the carbon has been determined in the first depth 

 samples. 



