CHArTER VI 11 



KXPERI.MENTS IPdN THE CoNTINroiS crvOWlll (>l MCI MINOrS 



cr.ops 



I. The Continuous Growtli of Beans on tlie same land, Geeseroft I'icld. 

 II. The Continuous (irowtli of Red Ch)ver on ordinary Arahic Land. I loos 

 Field, 

 ill. The Continuous Growth of Clover on Rich (Jarden Soil. 

 Referenees. 



I. — The Continuous Growth of Beans on the same land, 

 Geescroft Field. 



From the outset of the Rothamsted Experiments repeated 

 attempts have been made to grow leguminous crops year after 

 year on the same land. The particular importance of these 

 attempts comes from the special po.sition occupied hy the 

 leguminous plants. It is well known that ordinary farming 

 ^'xperience considers that the land requires a "rest" before the 

 growtli of any of these crops is repeated. Satisfactory crops 

 of clover are rarely obtained except at intervals of four year.s, 

 and on many soils even six or seven years nnist elapse before 

 the gi'owth of clover can l)e renewed with any prospect of 

 success. Not only does land l)ecome "clover sick." but the 

 farmer considers it will equally become b(>an oi- ])ea "sick"; 

 even lucerne, though it stands without failure foi- five or six 

 years or more, rarely succeeds when re-sown innncMJiately after 

 the removal of a previous crop of the same kind. The 

 leguminous crops of course ccmtain far greater auiounts of 

 nitrogen than any others, but it is now known that the greater 

 part of this is obtained from the atmosphere, so that the 



