8 o6 
Journal of Agricultural Research 
Vol. XXIV, No. 9 
The osmotic pressure of the sap of leaves from trees in the sand cul¬ 
tures was 20.80 atmospheres and that of leaves from the soil cultures 
was 21.03 atmospheres. The Ph of the former was 6.00 and that of the 
latter 5.80. We can not regard these differences as very significant. 
Can 85, as well as the other cans of the series 84-88, inclusive, con¬ 
tained soil obtained from an uncultivated hillside near Riverside, Calif. 
The hygroscopic moisture content of the soil was determined and the 
soil was brought to a suitable moisture content. 
The cans of soil were brought to a given weight at frequent intervals 
by the addition of distilled water or nutrient. During the experimental 
period (May 21, 1920, to September 20, 1921) can 85 received the fol¬ 
lowing additions of salts. 
Salts. 
Amounts 
added. 
KNO,. 
Gm. 
9.89 
14.85 
0. 46 
25.27 
4* 05 
0. 17 
0. 0108 
MgS04+7H20.. 
NaCl. 
Ca(N 03 ) 2 + 4 H 20 . 
KH2P04. 
KcoC CAHdOfi)^ . 
MnS 04 + 4 H 20 . 
Plate 3, B, shows a typical tree in the soil series (84-88). The growth 
in sand compared very favorably with that in soil. 
In November, 1920, after the addition of distilled water to cans i and 
2, the first 500 cc. of percolate obtained from both cans were analyzed 
for the PO4 and NOg content. The results given below indicate that an 
excess of both ions was present. 
Parts per million. 
PO4 
NO, 
Can I. 
55-7 
65-5 
i »329 
886 
Can 2. 
The soil in can 85 received only distilled water from May, 1920, to May, 
1921, after which tap water was used. Hoagland’s nutrient was occasionally 
added. Soil samples were taken from can 85 onOctober 8,1920, and also in 
September, 1921. A partial analysis of a i to 5 aqueous extract of the dried 
soil gave the following results when expressed in terms of the dried soil: 
Soil samples from can 85, October 8, ig20. 
Parts per million. 
Ca. 22 
Mg. 9 
Na-f-K (calculated as Na). 3 
Total solids as sulfates. 128 
SiOa. 19 
Parts per million. 
Cl. 18 
HCO3... 76 
SO4. 15 
NO3.. 40 
Ph of extract (colorimetric). 6. 6 
Soil samples from can 8$, September, ig2i. 
Parts per million. 
Ca. i8 
Mg. 8 
Na. 4 
K... 27 
Total solids. 313 
Si02. 36 
Parts per million. 
Cl.. 31 
HCO3 . 61 
SO4. 44 
NO3. 22 
Ph of extract (colorimetric). 6. 6 
