ANNIVERSARY ADDRESS 9 



analysis of Clover nitrogen is the prominent ingredient, 

 whereas phosphoric acid and potash will encourage them, 

 though only weakly represented in the chemical analysis. 

 Though in general practice things are never carried to 

 the extremes they are at Rothamsted, yet the plots 

 there show the direction in which different manures 

 tend to change grass lands. This Rothamsted old pasture 

 land is known to have been lying untouched for at least 

 some centuries, and at the beginning of the experiment 

 in 1856 the herbage on all the 20 plots was apparently 

 uniform. The soil all over the 7 acres experimented on 

 was a stiff, reddish loam, the individual plots being from 

 a half to one eighth of an acre, and, as has been said, 

 being cut for hay every year since the experiment began ; 

 and, with the exception of two, all the plots have 

 received manurial treatment of some kind, the manuring 

 of most of them having been continued without change 

 through all the intervening years. The herbage on 

 this grass land comprises, besides numerous genera and 

 species of the Gramineous and Leguminous families, 

 representatives of some twenty other natural Orders in 

 about fifty different species. "So complicated have been 

 the manifestations of the struggle in plant-life that has 

 been set up as the result of this treatment, that even 

 after many — about 50 — years' work both in field and 

 laboratory, many points of great general interest are 

 still open to future research." These experiments were 

 originally taken up and arranged from an agricultural 

 point of view, but to use the words of Lawes and 

 Gilbert's report, this " investigation of the effects of 

 different manures on the mixed herbage of grass land 

 has led us far beyond the limits of a purely agricultural 

 problem, and has afforded results of more interest to the 

 botanist, the vegetable physiologist and the chemist, than 

 to the farmer." 



In one of the later reports of the Rothamsted grass 

 experiments, Mr Hall, the Director, says; — " In dealing with 







