122 The Rothamsted Barley Experiments. 



V;iL EXPERIMENTS ON THE CONTINUOUS 

 GROWTH OF BARLEY UPON THE SAME LAND 

 FOR THIRTY-TWO YEARS. 



THE experiments on the continuous growth of barley on the 

 same land have now been in progress for nearly a second 

 period of twenty years, and it is desirable to examine the 

 results as nearly as possible down to date. Considering first 

 the yields without manure and with farmyard manure for a 

 period of thirty-two years (1852-1883), it appears that, 

 without manure, the yield in two years the third and fourth 

 was in each case over 30 bushels per acre ; in six of the 

 first thirteen years the produce was between 20 and 30 

 bushels, but it never afterwards reached 20 bushels ; whilst 

 in twenty -four out of the thirty- two years the yield was less 

 than 20 bushels in two of these it amounted to only 10 

 bushels, and in one year (1879) to only 6 bushels. The 

 tabulated results indicate that, independent of the fluctua- 

 tions due to season, there was a progressive decline due to 

 exhaustion, notwithstanding that the last four years gave a 

 higher average than any other four in the last sixteen years. 

 It is further discoverable that, without manure, there is a 

 decline in the produce of barley grain of 31*4 per cent, over 

 the second sixteen years, compared with the first sixteen. 

 This decline is considerably greater than was found in the 

 case of wheat, a circumstance doubtless due to the shorter 

 period of growth, and the greater dependence on the surface 

 soil, in the case of barley, exhaustion being thereby sooner 

 manifested. 



With farmyard manure, as with no manure, there is very 



