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20. — XoTES ON THE BoTANY OF THE EXPERIMENTAL GrASS PlOTS 

 AT lioTHAMSTED, HERTFORDSHIRE. 



By John J. Willis. 



Communicated by J. Hopkinson, Hon. Sec. 



[Read 12ih December, 1878.] 



Among the numerous experiments conducted at Rothamstcd by 

 Messrs. Lawes and Gilbert, there are none more interesting, certainly 

 not to the botanist, than those made on permanent meadow land, 

 because, independently of their value in practical agriculture, they 

 afford great facilities for the study of botany in all its various 

 branches. Our meadow lands comprise, as is well known to 

 botanists, not only a great number of genera and species belonging 

 to the grass family — the natural order Graminacese — but also 

 various members of other families of plants. 



In the year 1856 Mr. Lawes set apart about eight acres of grass 

 land in his park at Rothamsted, for the purpose of investigating the 

 comparative efPects of different manuring substances upon permanent 

 grass ; in the first instance probably to determine the best means of 

 increasing the gross amount of produce. But not only has the 

 general character of the herbage as to vigour, colour, date of 

 ripening, etc., materially altered, but the composition of the 

 produce has been entirely changed under this treatment. The 

 portion of land selected by Mr. Lawes for these experiments 

 is composed of a heavy loam, with a red clay subsoil of several 

 feet in depth immediately overlying the Chalk ; and it has 

 probably been laid down with grass for some centuries. l^o 

 fresh seed has been artificially sown within the last fifty years 

 certainly, nor is there a record of any having been sown since 

 the grass was first laid down. As previously stated, the experi- 

 ments commenced in the year 1856, at which time the character 

 of the herbage appeared uniform over all the plots. The por- 

 tion of ground was divided into twenty plots of from a quarter 

 to half an acre each, and in most cases the same description of 

 manure has been applied year after year to the same space of 

 ground, two pieces being left as test plots and entirely unmanured; 

 and the results, which have been fully and carefully noted, are 

 very extraordinary. 



Besides weighing the produce obtained by the different manures 

 as hay, and taking samples for the determination of its chemical 

 composition — namely, dry matter, ash, nitrogen, woody fibre, fatty 

 matter, etc. — carefully averaged samples are taken in each fifth 

 year from all the plots, and every year from selected plots, and 

 submitted to careful botanical separation, the per-centages by weight 

 of each species in the mixed herbage being determined. This is 

 necessarily a most tedious and lengthy proceeding, occupying a 

 period of several months in the laboratory, and requiring consider- 

 able skill at the identifications — a labour which appears to present 



