44 



each separate sample, and also in an equal mixture of the four. Six 

 other samples, each 6 by G by 9 inches, were also taken from each of 

 the two portions, and the six samples representing each portion were 

 mixed, and the nitrogen determined in the mixture. At each place 

 corresponding separate samples were taken, and mixtures made, re- 

 presenting respectively the second and the third 9 inches of depth. 

 In all cases three and in many four determinations of nitrogen were 

 made on each sample. The following table gives the mean results on 

 each of the four separate samples, the mean of these, the mean on the 

 mixture of the four, the mean on the mixture of. the six, and the mean 

 of all : — 



Table XIV. 



Experimental Clover and Barley Land. 



[Nitrogen per cent, in dry Mould, first 9 inches.] 



The determinations on the individual samples given in the upper 

 pr tion of the table (XIV), forcibly illustrate the inapplicability of 

 results obtained on single samples of soil. But the accordance of 

 the mean results of the three sets of determinations for the clover 

 land, and again of the three for the barley land, can leave no doubt 

 whatever that there was a considerably higher percentage of nitrogen 

 in the first 9 inches of the clover ground than to the same depth of 

 the barley ground. 



The results must, indeed, be accepted as indicating a marked distinc- 

 tion, which, in direction, is entirely consistent with what is known of 

 the influence of a clover crop as a prepai'ation for a succeeding cereal 

 one, and entirely consistent with the results actually obtained with the 

 barley succeeding the clover. It is, however, difficult, to suppose 



