Jan. 6,1923 
Sand Drown , a Chlorosis of Tobacco 
3i 
Table I.— Osmotic concentration of the sap of tobacco leaves and the ash of the sap y as 
affected by the chlorid and the sulphate of potassium 
Fertilizer treatments 
Osmotic concentration of sap (in atmospheres). 
Osmotic concen¬ 
tration of ash of 
sap (in atmos¬ 
pheres). 
July 22. 
July 24. 
July 26. 
July 30. 
: Average. 
July 32 . 
July 24. 
•General fertilizer test plots: 
N+P . 
N+P+80 pounds K 2 O f 
as sulphate .. 
N+ P-f 160 pounds K 2 0 , 
as sulphate. 
P-f-80 pounds K 2 0 , as 
sulphate.. 
N-f80 pounds K 2 0 , as 
sulphate . 
Average moisture per¬ 
centage of soil of plots 
9-346 
II. 060 
8-937 
8. 540 
8.396 
9. 021 
IO. 53O 
8. 949 
8.492 
9 - °93 
! 9 - »57 
j 9.418 
: 8.576 
8.215 
8.913 
7.878 
9 - 875 
7.987 
7 - 95 1 
: 8.937 
: 8.652 
! 10. 220 
8. 612 
; 8.299 
2. 929 
6. 855 
5-940 
5 - 013 
1. 869 
6. 012 
7 - 349 
6. 266 
4.917 
7. 0 5.5 i 7.25 j 
9.0 
Fertilizer treatments 
Osmotic concentration of sap (in atmospheres). 
Osmotic concen¬ 
tration of ash of 
sap (in atmos¬ 
pheres). 
July 20. 
July 2 3. 
July 25 . 
July 29 . 
Average. 
July 20. 
July 23. 
Special potash test plots: 
N+P . 
N+P+24 pounds K a O, 
as chloride . 
N+P+24 pounds K a O, 
as sulphate . 
N+P+80 pounds K a O, 
as chlorid . 
N+P+80 pounds K 2 0 , 
as sulphate . 
Average moisture per¬ 
centage of soil of plots 
7-734 
9 - 574 
8. 768 
10. 070 
9-^35 
8. 191 
8. 720 
8. 780 
10. 670 
8. 805 
8. 504 
10. 240 
9. 298 
10. 760 : 
10. 280 j 
8. 071 
8. 600 
8. 167 
9-959 
8. 528 
8.125 
9. 283 
8- 753 
IO. 36O 
9.312 
°- 9 J 7 
3. 086 
2. 712 
7.7IO 
5. 182 
1. 748 
2. 868 
3-351 
8. 191 
4. 929 
8.0 
5-5 
i 
9.0 
9.0 
a N*=32 pounds nitrogen per acre, in form of dried blood. P=64 pounds phosphoric acid per acre, in 
form of add phosphate in first series and precipitated bone in second series. 
Concerning weather conditions during the period of observation it may 
be stated that cloudy weather, with showers, prevailed July 17, 19, 24, 
27, and 31, with sunshine on all other days, except for a few thunder 
showers of brief duration. Rainfall of consequence occurred only as fol¬ 
lows: July 17, .33 inches; July 24, 1.55 inches; July 27, 1.37 inches; 
July 30, 0.82 inch. The soil, which is a light, sandy loam, has a low 
water-holding capacity, and there was a wide range in degree of satura¬ 
tion during the period of study. The osmotic concentration of the sap 
of the plant, however, does not appear to be definitely correlated with 
the water content of the soil. In general, increased application of potash 
salts to the soil increased the osmotic concentration of the sap and the 
chlorid was decidedly more effective than the sulphate in this respect. 
