Aug. 19,1918 Availability of Potash in Soil-Forming Minerals 
303 
Table V .—Rate of application of plant nutrients 
Carrier. 
Quantity 
of carrier 
per pot. 
Quantity of plant nutrients 
(pounds per acre of 2,000,000 
pounds of soil). 
Nitro¬ 
gen, 
Phos¬ 
phoric 
acid. 
Potash, 
Time. 
Dried blood.. 
Grains. 
4. 834 
13 - 424 
3-570 
7. 140 
21. 488 
42.976 
19. 872 
39 - 744 
13- 348 
27. O96 
12. 552 
25. 104 
33- 420 
66. 840 
73 
Acid phosphate. 
224 
(«) 
Potassium sulphate.. f . 
0000000000 
0000000000 
2 potassium sulphate. 
Biotite.... 
8 
( a ) 
(a) 
( a ) 
( a ) 
(«) 
2, OOO 
4, 000 
2 biotite. 
Muscovite. 
2 muscovite. 
Orthoclase. 
2 orthoclase. 
Microcline. 
2 microcline.. 
Precipitated calcium carbonate. 
2 precipitated calcium carbonate. 
a Not determined. 
Enough water was added each day, when necessary, to keep the soil 
well moistened during periods of plant growth. 
Acid-washed quartz was placed over each pot after seeding to act as 
a mulch. 
OAT CROPS 
On March 24, 1916, 20 seeds of the Burt variety of oats were planted 
to each pot. After germination the plantlets were drawn down to a 
uniform stand of 12 per pot. On the following June 10 the oat crop was 
harvested after reaching maturity. Owing to the inability of removing 
all the roots, only the portion of the plants above ground was considered. 
Potash was determined separately in the grain and straw of each pot. 
Table VI contains the data obtained. 
Table VI .—Weight of oat crop and potash removed from soil 
Treatment. 
Dry matter (grams). 
Potash removed from soil (grams). 
Grain. 
Straw. 
Total. 
Aver¬ 
age 
total. 
Rela¬ 
tive 
rank 
of av¬ 
erage. 
Grain. 
Straw. 
Total. 
Aver¬ 
age 
total. 
Gain 
over 
no pot¬ 
ash. 
Potassium sulphate. 
13-8 
24.9 
38.7 
fo. 065 
0.306 
0.371 
) 
Do. 
16.4 
22.4 
38.8 
■ 37.0 
82.4 
\ .083 
.300 
•383 
fo.363 
0.305 
Do. 
12.7 
20.9 
33 * 7 
1 .062 
. 284 
.346 
1 
2 potassium sulphate. 
17.2 
27.6 
44.8 
[ .086 
.366 
•452 
1 
Do. 
18.0 
24.9 
42.9 
■ 44-8 
99-8 
< .088 
.36 6 
•454 
f -454 
•396 
Do. 
20.0 
26.8 
46.8 
( *092 
-367 
•457 
1 
2 potassium sulphate plus cal¬ 
cium carbonate. 
21. X 
28.0 
49 *i 
I 
f -107 
•434 
•541 
i 
Do. 
20.0 
25.0 
45*0 
1 - 44.8 
99.8 
< .092 
•425 
.417 
\ -482 
.417 
Do. 
17.6 
22.8 
40.4 
J 
f .088 
.400 
.488 
J 
