230 



Dr. J. B. Lawes and Dr. J. H. Gilbert. [June 19, 



XXIII. " Agricultural, Botanical, and Chemical Results of Ex- 

 periments on the Mixed Herbage of Permanent Meadow, 

 conducted for more than twenty years in succession on 

 the same land." By J. B. Lawes, LL.D., F.R.S., F.C.S., 

 and J. H. Gilbert, Ph.D., F.R.S., F.C.S., F.L.S. Received 

 June 16, 1879. 



(Abstract.) 



In the experiments at Rothamsted with different manures, wheat 

 has now been grown for thirty-six years in succession on the same land, 

 barley for twenty-eight years, and oats for nine years. Somewhat in like 

 manner, but with some breaks, beans have been grown over a period of 

 more than thirty years, clover for many years, and " root-crops " (tur- 

 nips, sugarbeet, or mangel-wurzel) also for more than thirty years. Each 

 of these individual crops has exhibited certain distinctive characters 

 under this unusual treatment. But, withal, those of the same natural 

 family, wheat, barley, and oats, for example, have shown certain 

 characters in common, those of the Leguminous family characters 

 widely different, whilst the so-called root-crops, belonging to the 

 Cruciferous and Chenopodiaceous families, have exhibited character- 

 istics differing from those of either the Gramineae or the Leguminosa?. 



Compared with the conditions of growth of any one of these indi- 

 vidual crops grown separately, those of the mixed herbage of grass 

 land are obviously extremely complicated. Thus, it comprises, besides 

 numerous genera and species of the gramineous and leguminous 

 families, representatives also of many other natural orders, and of 

 some of great prominence and importance as regards their prevalence 

 and distribution in vegetation generally. And if, under the influence 

 of characteristically different manuring agents, as has been the case, 

 there have been observed notable differences in the degree of luxuriance 

 of growth, and in the character of development, even between closely 

 allied plants when each is grown separately, and much greater differ- 

 ences between the representatives of different families when so 

 separately grown, might we not expect very remarkable variations of 

 result, when different manures are applied to an already established 

 mixed herbage of perhaps some fifty species growing together, repre- 

 senting nearly as many genera and more than twenty natural orders ? 



Such, far beyond what could have been anticipated, has been the 

 case in the experiments described. So complicated, indeed, have 

 been the manifestations of the " struggle " that has been set up, that, 

 even after more than twenty years of laborious experiment, both in 

 the field and in the laboratory, and following up both the botany and 

 the chemistry of the subject, we can hardly claim to have yet done 



