June a , 1923 
Orange Trees in Sand and Soil Cultures 
813 
sap required 7.05 cc. of N/io alkali. Protein formation or decomposi¬ 
tion may bring about the formation of organic acids (<9, p. 237-24^), 
Since a large portion of the calcium in many plants is used for the neu¬ 
tralization of acids, there should be more calcium in plants producing 
large amounts of acid. The analyses indicate that this may be the case 
with orange trees, namely, that one of the chief functions of calcium in 
the tree may be the neutralization of the organic acids. Opportunity 
to test out this hypothesis further will be afforded in cultures now 
growing. 
SUMMARY 
(1) Data have been presented to show that the nutrition of young 
trees may be studied in a quantitative way under controlled conditions 
by the procedure described. 
(2) The reaction of the nutrient solution used shifted from Ph 5.2 to 
5.9 when the solution was in contact with sand, and further toward the 
neutral point when in contact with sand containing citrus rootlets. 
(3) The relative amounts of new growth produced by the trees grown 
in sand or soil cultures were quite similar when one estimates the ratio 
between total dry weight and the dry weight of corresponding portions. 
The ratio of total transpiration to total dry weight of tree was approxi¬ 
mately the same in both cases. The rootlets of the trees grown in soil 
were much more finely divided than those grown in sand. 
(4) Analyses of the trees showed both a high calcium (Ca) content and 
a high Ca/N ratio. 
(5) The percentages of total phosphorus in leaves and shoots were 
approximately equal. 
(6) The leaves and rootlets contain in their dry matter the greatest 
percentage of total ash and of nitrogen, 
(7) The ash obtained from all parts of the tree contained large amounts 
of carbonate, although the rootlets contained less than the other portions. 
(8) The ash of all parts of the trees was markedly rich in potassium 
and relatively poor in sodium. The former was relatively uniform in 
the various parts of the tree, but the distribution of the latter was more 
variable. 
(9) The various parts of the trees likewise contained large amounts of 
calcium and relatively small amounts of magnesium. Both constituents 
show fairly uniform distribution throughout the tree. 
(10) The distribution of sulphate in the ash of the various parts of 
the tree is quite uniform with the exception that the rootlets contained 
nearly three times as much as the other portions of the tree. 
literature cited 
(1) Briggs, Lyman J., J^nsi^n, C. A., and McLanr, J. W. 
1916. MOTTrH-I.KAR OF CITRUS TREKS IN RELATION TO SOIL CONDITIONS. In 
Jour. Agr. Research, v. 6, p. 721-740, 4 fig., pi. H (col.), 96-97. 
(2) -and ShanTz, H. L. 
1916. DAILY TRANSPIRATION DURING THE NORMAL GROWTH PERIOD AND ITS 
CORRELATION WITH THE WEATHER. In Jour. AgT. Research, v. 7, 
p. 155-212,18 fig., pi. 5-6. 
(3) Co viLLE, Frederick V. 
1914. THE FORMATION OF lEafmold. In Ann. Rpt. Smithsn. Inst. 1913, p. 
333 - 343 - 
(4) Hedrick, U. P.', and Anthony, R. D. 
1919. TWENTY YEARS OF FERTILIZERS IN AN APPLE ORCHARD. N. Y. (Geneva) 
Agr. Exp. Sta. Bui. 460, p. 71-96. 
