THE ROTHAMSTED EXPERIMENTS 345 



Notwithstanding this somewhat restricted character of the 

 general plans, the records of Rothamsted are the greatest source of 

 knowledge concerning many of the most fundamental problems 

 of soil fertility; and in justice to the American farmer and student 

 of permanent agriculture, the author cannot do less than to repro- 

 duce the following records of Rothamsted investigations that seem 

 to bear most directly upon the maintenance of soil fertility as 

 measured by crop yields: 



1. Crops grown in rotation on Agdell field, with records since 

 1848. 



2. Wheat grown continuously on Broadbalk field, with records 

 since 1844. 



3. Wheat alternating with fallow on Hoos field, with records 

 since 1851. 



4. Barley grown continuously on Hoos field, with records since 

 1851. 



5. Potatoes grown continuously on Hoos field, twenty-six years' 

 records (1876 to 1901). 



6. Hay grown continuously on the permanent Park, with records 

 since 1856. 



7. Experiments with root crops on Barn field, with records since 



This mass of valuable data is given in order that one who so 

 desires may study these results from any point of view and draw 

 his own conclusions. Space is also taken for a brief discussion of 

 the summaries of the Rothamsted laboratory investigations, and 

 frequent reference to these data must be made for proof of estab- 

 lished principles. 



AGDELL FIELD ROTATION CROPS * 



The Agdell field includes two series of six plots each. On one 

 series a four-year rotation is practiced, as follows : 



First year .... Swede turnips (rutabagas). 



Second year .... barley. 



Third year .... clover (or beans). 



Fourth year .... wheat. 



