Experimental Crops at Rotliamstcd. 
103 
than that of tlio uiiinanurcd plot at the corresponding depth. 
The third, fourth, fifth, and sixth 9 inches were very strikingly 
different in appearance from the corresponding Layers of either 
of the other two plots ; the clay, instead of being of a compara- 
tively uniform reddish yellow colour, was very much mottled or 
veined, showing a mixture of yellow, grey, red, and brown, with 
the yellow and grey predominating. So much was this the case 
that when the samples were powdered they were of a yellowish 
grey colour, instead of reddish yellow ; and the lighter or less 
yellow the greater the depth of the sample, that of the sixth 
1) inches being the lightest of all. 
There was, perhaps, more of natural grey vein in the subsoil 
of this than in that of the other plots, but the difference in 
colour and texture was too great to be so accounted for. Upon 
the whole the lower layers were softer and more soapy than in 
the case of either Plot 3 or Plot 9 ; though, as Table III. at 
page 98 shows, they contained a considerably less percentage 
of moisture. Indeed, the subsoil of this plot had much more 
the appearance of disintegration from some cause than that of 
either of the others ; it was consequently much more easily 
worked, and especially more so than that of the unmanured plot, 
which was very tough and hard. 
To sum up these distinctions : it is seen that not only did 
different plants become dominant according to the different 
condition of the plot as to manure, but those which prevailed 
on the unmanured land, though numerous, had much finer and 
much less vigorous roots ; the raw clay of the subsoil was much 
less changed ; and it had yielded up very much less moisture to 
the growing crop. On the plot manured with mineral manure 
and ammonia-salts free-growing grasses predominated ; but 
chiefly those whose underground habit of growth was such as 
rendered them dependent for their food and moisture in great 
measure on that which is to be found in the upper layers of the 
soil. Still, owing to the increased vigour of growth under the 
influence of the manure, it is seen that moisture was obtained, 
either directly by the roots of the plants, or by capillary action 
induced by the pumping out of the upper layers, from the 
extreme depths to which the samples were taken ; and, from 
the great difference in the percentage of moisture at that depth 
compared with that of the unmanured plot, there is no doubt 
that the action extended deeper still. On Plot 14, on the other 
hand, where nitrate of soda was applied, the plant which con- 
tributed about half the produce had roots of a very characteristi- 
cally downward tendency. We find the soil, to the depths 
examined, pumped drier still ; and, coincidently, the drought 
has comparatively little affected the amount of the crop. 
