546 Brenchley and Jackson . — Root Development of Barley and 
better development of laterals than did the unmanured, but no other 
differences, either in size or general appearance, could be observed. The 
original intention was to examine the held roots periodically, but it was 
found impossible to do this and to carry on the root washing at the 
laboratory at the same time. Accordingly the trench method for 
examining the roots was not attempted until August, 168 days after sowing. 
At this time the barley was mature, and very little root system was found 
either in the unmanured or in the superphosphate plots. This may have 
been due to several causes ; possibly the root system had been better 
earlier in the season, but the amount of root had decreased as the grain 
matured, a condition similar to that found in the pot cultures. The 
conditions of growth were as follows : The tilth was poor and the soil was 
in a very starved condition, no manure having been applied for years, and 
the clayey subsoil approached very near the surface. These conditions may 
easily have affected the roots adversely. Several of the larger roots were 
traced to their tips and most of their laterals were found to be perfect, but 
few were longer than in., nor were they branched. The majority of the 
roots were confined to the upper few inches of the soil, the roots running 
down at a slight angle to a depth of 3 in. or 4 in. When the poor root 
development was discovered the experimental plots were abandoned and 
the ordinary farm barley was examined as described above. This soil was 
in better condition than that on the experimental plots, and the barley 
was still in the green stage. About four plants grew together in the drill, 
giving the appearance of one tillered plant, whereas in reality very few of 
the plants showed any tillering. The root system was mostly confined to 
the top 2 in. of soil ; some roots ran down obliquely into the soil, and a few 
went down vertically, but none of them were observed to reach below the 
top 6 in. 
The plants washed out from the cubes of soil (see method above) had 
been manured with superphosphate. They showed 2-4 tillers per plant, 
and a fairly well developed root system. From each crown a number of 
short roots, ij to in. long, spread out in all directions, penetrating to 
a depth of 1 in., while a few roots were longer, much branched, and ran 
down obliquely to about 8 in. The greater part of the root system, 
however, was again in the top 2 in. Each plant showed one or two roots 
which had rotted back to a point above 5 in., which would correspond to 
a depth of 3 to 4 in. in the soil ; probably the root here entered a bad 
stratum, which could not be penetrated. Some rather thicker and less- 
branched roots were observed coming from the node, while the finer, more 
branched roots came from the grain. The plants grown with farm-yard 
manure were much better than any of the previous field specimens — 
a typical plant having about seven tillers and many long roots with 
abundant laterals concentrated in the upper 5 in. of the root. There were 
