200 



CROPS GROWN' IN ROTATION 



systems no manure, minerals without nitrogen, and a complete 

 manure on the successive crops in the 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 course, 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 seven 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. 



TABLE LXVII. Crops grown in rotation, Agdell Field. Effect of Clover or 

 Beans en 1Jie following Wheat Crops. Total produce per acre. 



* 7 years (1874, '82, '86, '94, 1902, 1906, and 1910). 

 t 7 years (1875, '88, '87, '95, 1903, 1907, and 1911). 



J 8 years (1854, '58. '62, '66, '70, 78, '90, and '98). 

 8 years (1855, '59, '63, '67, 71, 79, '91, and '99). 



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 manures a large bulk of clover is grown, 

 averaging 47 cwt. of clover hay, and notwithstanding that all 



