ANNIVERSARY ADDRESS 13 



phosphate to the extent of 14 per cent., has quite disappeared, 

 while Rumex Acetusa has gone up from 2 per cent, to 

 17 per cent. Nitrate of soda alone has not proved quite 

 so fatal to Leguminous plants, as a few weak specimens 

 are found. The Sheep's Fescue has been crowded out 

 by the Oat Grasses, and Centaurea nigra and Plaiitago 

 lanceolata are found in abundance. The acid nature of 

 soil treated with such persistent quantities of sulphate 

 of ammonia was exemplified by a small portion of the 

 plot being supplied with a dressing of chalk, which 

 resulted in the disappearance of the Sorrel which had 

 increased by 15 per cent. With nitrate of soda a new 

 plant had appeared and thriven, namely, Anthriscus 

 sylvestris (Beaked Parsley), which first showed itself in 

 this plot in 1867, but now occupies about 10 per cent, of 

 the whole plot. Another notable feature is the large 

 increase of Yorkshire Fog, which has gone up from 

 5 per cent, to 50 per cent. When potash and phosphoric 

 acid ha*ve been applied without the nitrogenous manures, 

 Leguminous plants have increased to 24 per cent., and, 

 judging from the hay crop, have been sufficient to keep 

 up the soil fertility. Where potash has been omitted 

 and only phosphoric acid used, Lathyrus pratensis is 

 specially abundant, but Clovers have diminished and conse- 

 quently the general fertility, though Lotus corniculatus 

 is still healthy. 



I think I have said enough to show the extreme 

 interest of these Rothamsted plots ; and an examination 

 of the results with a knowledge of the habits of the 

 plants as to root, stems, leaves, tillering, partiality to 

 shade or sunshine, requirements as to soil, moisture, etc., 

 gives in many cases, though not in all, a key by which 

 the causes of the changes may be arrived at. It would 

 almost seem as if a plant with the power of taking 

 a natural supply of a manurial ingredient easily, resented 

 the application of an artificial supply. 



