Experimental Crops at Rothamsted. 
101 
Fcstuca ovina (sheep's- fescue), Lolinm perenne (rye-grass), Dactylis 
glomerata (rough cock's-foot), Avena Jiavescens (yellow oat-grass), 
and among weeds Antliriscus sylvestris (wild beaked-parsley), 
coming next in order of prevalence. And, whilst the plants most 
encouraged by the ammonia-salts have a tufty habit of growth 
above ground, and a tendency to luxuriate within a limited range 
beneath the surface, some of those most favoured by the nitrate 
of soda, and especially under its influence, are very different in 
character, not growing in tufts, but producing comparatively uni- 
formly dense herbage, with many stems, comparatively few root- 
leaves, and roots having a characteristically downward tendency, 
those of the Bromus mollis es])ecially (which contributed such a 
large proportion of the whole crop) being strong and wiry, and 
descending far into the subsoil. 
The sectional examinations, indeed, showed great differences in 
the character of the turf, in the prevalence and character of de- 
velopment of the roots within and below it, and in the character 
of the soil and subsoil, as the following brief abstract of the 
observations made will show. It should be first stated, however, 
that whilst on the square yard selected as characteristic of the 
unmanured plot, there were found 9 graminaceous, 4 legu- 
minous, and ll miscellaneous species — in all 24 ; on that of Plot 
9, having mineral manure and ammonia-salts, there were only 
6 graminaceous, no leguminous, and only 3 miscellaneous spe- 
cies ; and on that of Plot 14, receiving mineral manure and nitrate 
of soda, again only 6 graminaceous, only 1 leguminous, and 2 
miscellaneous species. 
Owing to the great complexity of the herbage on the un- 
manured plot, including a comparatively large number of legu- 
minous, and miscellaneous or weedy species, some fleshy roots 
were observed at a considerable depth. The turf consisted of a 
complex network of fine roots and fibrils, which were much 
less in size and strength than in the case of either of the manured 
plots. These fine roots seemed to have more or less complete 
possession of the soil to a depth of about 6 inches, and some of 
them then showed a downward tendency ; becoming, however, 
much fewer, and even in the second and third 9 inches extremely 
fine ; and at a depth of about 40 inches they were as fine as a 
fibre of silk or a spider's web. It was concluded, though not 
with great certainty, that the roots found at the greatest depth 
were those of Agrostis vulgaris and Bromus mollis. The sample 
ot the first 9 inches of the unmanured soil possessed the character 
of mould not much less than that of the manured plots ; the second 
9 inches was also very much altered from the character of the clay- 
subsoil ; but below this point very slight difference was observ- 
