200 



CROPS GROWN IN ROTATION 



III. — The Effect of the Growth of Clover or Beans on 

 THE Succeeding Crops. 



It has already been stated that one of the main objects of the 

 experimental field is to compare the results of growing a crop 

 like beans or clover as the third item in the rotation instead of 

 taking a bare fallow. Of com^se, historically, this change from 

 bare fallow to clover marks one of the great advances in 

 agricultural practice, but its complete justification has only 

 been possible in the last few years, since the power of the 

 leguminous plants to fix atmospheric nitrogen has been known. 

 In the Agdell field clover has been grown six times and beans 

 eight times during the period under experiment. Table 

 LXVII. shows the average crops of each separately, together 

 with the total produce of the succeeding wheat crop on the 

 fallowed and cropped portions respectively. 



'J' ABLE LXVII. — Cro^s grown in rotation, Agdell Field. Effect of Clover 

 or Beans on the following Wheat Crops. Total produce per acre — 

 Mean of "Fed" and "Carted" 2Jortions. 



'■ 5 years (1S74, 1882, 1886, 1894, and 1902). 

 t 5 years (1875, 1883, 1887, 1895, and 1903). 



+ 8 years (1S54, 1858, 1862, 1866, 1870, 1878, 1890, and 1898). 

 § 8 years (1855, 1859, 1863, 1867, 1871, 1879, 1891, and 1899). 



The beneficial effect of the clover crop is at once apparent 

 from the table. On the unmanured plot the clover crop is a 

 small one, and apparently the nitrogen it has collected from the 

 atmosphere is not sufficient to compensate for the better tilth 

 and nitrification which are induced by a bare fallow. On the 

 plot receiving mineral manm^es a large bulk of clover is grown, 

 averaging 44*4 cwt. of clover hay, and notwithstanding that all 

 this is removed from the land the nitrogen accumulated in the 

 roots and stubble is sufficient to raise the total produce of the 



