534 Brenckley and Jackson. — Root Development in Barley and 
appearance in plants at different periods of growth, and the experiments 
were extended to include the relations between root and shoot growth. 
A considerable amount of information is available on the subject of 
the growth of the shoot and of the root of various crop plants, but there is 
not much literature dealing with the relation between shoot and root growth 
at various stages in the plant’s history. 
Experiments were carried out this year (1920) to investigate the root 
systems of plants growing in pots under controlled conditions and also of 
others growing under ordinary farm conditions in the field, and an attempt 
has been made to correlate shoot and root development. Wheat and 
barley were chosen for this investigation, both in the pot cultures and the 
field trials. 
Root System of Barley. 
Pot Cultures. 
The early stages of development were obtained by sowing the grain in 
small glazed earthenware pots, 7 inches in height and in diameter, holding 
6 \ lb. of soil. The soil used throughout the experiment was rather heavy 
farm soil mixed with 10 per cent, of sand to lighten it. Half the pots were 
unmanured and half had 0-7 grm. superphosphate mixed in with the soil. 
In each manurial series one half of the pots were sown with wheat and the 
other half with barley at the rate of two grains per pot in each case. When 
the shoots were about 1 in. high, the weaker plant in each pot was destroyed 
by cutting off the shoot, since pulling up by the root would probably have 
disturbed the roots of the other plant. At the same time a series of cultures 
in large pots, height 14 in., diameter 6 \ in., each holding 23 lb. soil, were set up, 
§ of which were left unmanured and f received grm. 1 superphosphate 
per pot. Seeds were sown as before — wheat on Feb. 21, barley on March 5. 
Some weeks later, on April 6, sodium nitrate and potassium sulphate were 
applied as top-dressings to some of the pots, the final series of manuring 
being as shown in the following table : 
Series 1 Unmanured. 
„ 2 „ + sodium nitrate. 
,, 3 Superphosphate 
„ 4 „ + sodium nitrate. 
„ 5 „ + potassium sulphate. 
Wheat sown Feb. 21, weight of grain 0*05-0*06 grm., top-dressed April 6. 
Barley „ March 5, 
The scheme adopted was periodically to examine the root growth of 
two plants with each type of manuring. The small pots were examined 
1 This is at the same rate as in the small pots. 
