M 



during the past three years, and it was found to yield exactly the 

 same as the mean of the two cereals grown separately during the 

 first two years, and in the third year the comparison was vitiated 

 by the failure of the oat crop. 



If there was an ill effect at any period it must have been 

 counterbalanced later, and in the end there was neither the decrease 

 of crop expected from some of the pot observations, nor the increase 

 claimed by the growers. To some extent the experiment is affected 

 by the difficulty of growing spring oats at Rothamsted, and it would 

 be a great advantage to have the experiment conducted in a district 

 where the mixture is said to be a success. 



There is evidence, however, that the sowing of a leguminous 

 crop with corn leads to an increase in the latter crop. 



Thus we have the three cases : (l) Mr. Pickering's observations 

 certainly indicate that one growing plant has a directly harmful effect 

 on another; (2) the dredge corn experiments indicate that no such 

 effect is finally produced ; and (3) other experiments indicate an 

 actual beneficial effect when one of the crops is a leguminous crop. 

 It is very necessary to clear up these apparent discrepancies, and 

 a series of experiments is in hand for the purpose. 



Agricultural Investigations at Rothamsted, 

 England, during a period of 50 years, by Sir J. 

 Henry Gilbert, M.A., F.R.S. (1893), price 3/- (Lawes 

 Agricultural Trust). 



Rothamsted, Un Demi-Siecle d y Experiences 

 Agronomiques de MM. Lawes et Gilbert, par 

 A. Ronna (1900), price 2/- (Lawes Agricultural Trust). 



A General Account of the Rothamsted Field Ex- 

 periments is given in The Book of the Rothamsted 

 Experiments, by A. D. Hall, M.A., price 10/6 (John 

 Murray). 



A short summary is given in The Guide to the 

 Rothamsted Experimental Plots, 2nd Edn., 1913, 

 price 1/- (John Murray). 



