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348 Twenty-FIrTH ANNIVERSARY REPORT. rigs 
of warmth, moisture and oxygen are indispensable to the develop- — 
ment of roots and that when these are present the rapidity of growth _ 
and the number of branches are dependent upon the amount of avail- 
able plant-food. In that stratum of the soil in which the balance ~ 
of these four conditions is on the whole most favorable to Loa 
growth, the roots develop fastest and this is doubtless one law that — 
governs their distribution.” ; 
“Market gardeners find transplanting young plants of as 
tomato, etc., while growing in a cold frame to be of great advantage 
in assisting them to endure the final removal to the open ground. ~ 
The question arose as to the cause of the benefit thus ascribed to a 
process that would appear to be in itself detrimental.” An inmvesti- 
gation “ indicated that the benefit chiefly arises from the longer roots 
being broken in transplanting which causes a compact growth of 
fibres near the base of the plant. This mat of fine roots carries the 
inclosed soil with it in the final transplanting and thus many of the 
feeding parts are in a condition to commence absorption at once ~ 
in their new home. The experiments showed that precisely the same 
result may be secured by sowing the seeds thinly in the frame 4 
and then severely root-pruning the young plants from time to 3 
time. Whether this checking of the root growth by transplanting or 
root pruning is in itself beneficial’ was not determined, the results 
of the investigation being inconclusive. “In experiments with 
young plants of cabbage and corn, root pruning seemed to increase 
the proportionate development of the root as compared with that of 
the top, but on the whole to retard growth. In every case where the — 
root pruning was performed in dry weather the results appeared in- 
jurious to growth.” : 
A mulching experiment showed “ that mulching the surface tends _ 
to bring the fibrous roots ” upward, the proportion of fibrous roots in 
the first two inches of soil being greater for the mulched than for 
the unmulched plants. It was noted that normally in cultivated fields 
roots are much closer to: the surface than is generally imagined. A 
numerous supply of roots was found in August between the rows in 
a field of sweet corn within an inch of the surface. A microscope 
showed that these roots were covered with root hairs; that is, they 4 
were feeding roots. Practically the same conditions were found in 
field corn and tobacco. In the language of the investigator the re- 
sults of this investigation are: F 
1st. “ The chief feeding ground of the roots of our hoed crops — 
including both those of field and garden is in the stratum of soil 
