248 A VISIT TO ROTHAMSTED. 



yet tlieir contribution to the general mass of vegetation was of 

 no account. 



On plot 15, where nitrate of soda alone had been given, the 

 appearance of the crop somewhat resembled plot 5, but here the 

 foxtail grass (Alopccurus pratensis), which formed no feature in 

 other plots, became the predominating grass. As in the case of the 

 other plots which had received nitrogenous manures, the clovers 

 and other legimiinous plants had disappeared, l)ut unlike the 

 ammonia plots a miscellaneous herbage of considerable variety 

 was seen flourishing on this plot. 



When in addition to -nitrate of soda the mixed mineral man- 

 ure was added, the whole character of the heritage was changed. 

 In the strong rough superabundant crops the foxtail grass was 

 no longer visible, but fescues, poas, oat grasses, and bent grasses 

 competed for the mastery. Leguminous, plants made their 

 appearance only to a very limited extent, but the miscellaneous 

 lierbage was considerable, and consisted mostly of dock sorrel, 

 ranunculus and a few umbelliferous plants. 



These experiments show clearly that a very intimate relation 

 subsists betw^een the different grasses and the various forms of 

 fertilizing agents, and that it is possi1)le by means of the latter 

 to exercise some kind of control over the character and relative 

 amounts of the grasses grown on meadow land. They shew that 

 some forms of manure encourage the growth of the sweeter 

 grasses and other plants that are valued as hay, and that others 

 favour the development of the coarser and more rapid growing 

 grasses, which in their young state are held in esteem as green 

 fodder. 



We come next to consider the experiments with barley which 

 have been going on on Hoos Field for about thirty years. The 

 system of manuring resembles in many respects that adopted for 

 the grass experiments. The primary object of these experiments 

 seems to have been to determine the extent to which nitro- 

 genous manures are necessary for the growth of white crops. 

 At the time of their commencement the use of ammonia salts or 

 nitrates as manure was very imperfectly understood, and it is 

 undoubted that the rapid increase in the popularity and intelli- 

 gent use of this most important class of manure were in great 

 measure due to the precise results obtained from the experiments 

 conducted at Eothamsted. 



The soil of Hoos Field resembles that of the Park. It has no 

 artificial drainage. It is divided into plots, each about a fifth of 

 an acre in extent. 



The amount of corn and straw, and the system of manuring 

 during the twenty-four years beginning in 1852, will ])e seen 

 from the subjoined table: — 



