788 
Journal of Agricultural Research 
Vol. XXIV, No. 9 
was added. The protective action of calcium carbonate against the 
toxic properties of an excess of manganese sulphate is demonstrated 
with soybeans. The plants receiving 50 parts per million of manganese 
in the neutral soil made a moderate growth, while in the corresponding 
pots of acid soil no plants were produced. 
After the dry weights were determined the leaves and stems of the soy¬ 
bean plants in duplicate pots were combined to make a composite sample 
for chemical analysis. The results of the analyses are given in Table VI. 
Table IV .—Analyses of composite samples of soybean plants grown after radish plants 
in Volusia and Dunkirk soils, with and without the addition of nutrients, MnSO^ and 
CaCO^ {results calculated on moisture-free basis) 
Acid reaction of soil. 
Neutral reaction of soil. 
Crop. 
Soil. 
No 
treat¬ 
ment. 
Miner¬ 
als. 
Miner¬ 
als plus 
S parts 
per 
million 
Mn. 
Miner¬ 
als plus 
10 parts 
per 
million 
Mn. 
CaCOs. 
CaCo3 
plus 
miner¬ 
als 
CaCOs 
plus 
miner¬ 
als and 
5 parts 
per 
million 
Mn. 
CaCOs 
plus 
miner¬ 
als and 
10 parts 
per 
million 
Mn. 
CaCOs 
plus 
miner¬ 
als and 
50 parts 
per 
million 
Mn. 
Ash. 
/Volusia.. . 
\Dunkirk.. 
Per ct. 
8. 38 
Per ct. 
12.43 
Per ct. 
13- 86 
Per ct. 
14- 24 
Per ct. 
9.48 
Per ct. 
12.52 
Per ct. 
12. 59 
Per ct. 
13 - 15 
Per ct. 
10. 72 
9-58 
13 -17 
13. 98 
14. 12 
II- 36 
12.50 
13-19 
13- 86 
9-37 
Fe. 
/Volusia,. . 
/Dunkirk.. 
•059 
. 078 
. 078 
. 069 
.068 
• 059 
.071 
1.06 
.114 
. 070 
. 070 
.066 
.051 
.050 
.052 
.047 
• 052 
. 082 
Mn. 
/Volusia.. . 
. 012 
. 012 
. 186 
•303 
.012 
. 014 
. 027 
. 042 
. 204 
/Dunkirk.. 
.013 
. 019 
. 162 
• 277 
. 069 
.105 
•346 
•697 
. 186 
Ca. 
/Volusia.. . 
/Dunkirk.. 
I. 19 
I. 69 
I. 89 
I. 81 
2 .05 
2.05 
2. 04 
1.96 
I. 62 
I. 90 
I. 87 
I. 60 
2. 12 
2.08 
1.62 
1.88 
1.84 
I- 71 
Mg. 
/Volusia. . . 
/Dunkirk. . 
•31 
• 29 
• 30 
.28 
•32 
•30 
.27 
.28 
.24 
•33 
•36 
•31 
• 29 
•31 
•34 
.28 
•25 
•36 
•p 
/Volusia. . . 
/Dunkirk. . 
•13 
•31 
•35 
•43 
.18 
• 27 
.24 
. 22 
•36 
ir. 
•23 
•45 
•SO 
• 55 
• 27 
.48 
.46 
.40 
•41 
ir 
/Volusia .. . 
1-43 
3-40 
3^ 62 
3-92 
1.40 
3 - 12 
3-05 
3- 05 
3-03 
/Dunkirk.. 
1-34 
2. 80 
3 - 39 
2. 20 
3 -SI 
3 - 71 
3 -SI 
3-34 
3-21 
N. 
/Volusia.. . 
3-40 
4. 06 
4. 07 
4.12 
3 - 69 
4. 16 
3-91 
4- 00 
4.49 
/Dunkirk.. 
I. 62 
4 - 25 
3.8s 
3 - 76 
1.86 
3-82 
3- 80 
3 - 76 
3- 96 
Table IV shows that the smallest percentage of ash was taken up by the 
plants grown in the untreated soils, while the largest percentage was 
found in the plants that had grown in the acid soil and to which 10 parts 
per million of manganese was added. Consider^ably more manganese 
than iron was taken up by the plants that grew in each of the acid soils 
to which manganese was added. Under neutral conditions more 
manganese thaii iron was absorbed by the plants that grew in the Dun¬ 
kirk soil. The results for calcium vary to some extent between the two 
soils but apparently more calcium was taken up by the plants that grew 
in the neutralized soil. The plants that grew in the Dunkirk soil con¬ 
tained more phosphorus than those that grew in the Volusia soil. The 
amounts absorbed under acid and neutral conditions were nearly equal 
in the Dunkirk soil. Considerably more potassium was taken up by the 
plants receiving mineral nutrients and manganese than by either the 
untreated or the soils to which only calcium carbonate was added. 
In the foregoing experiments with soils, the purpose was to determine 
the effect produced on the growth of plants in an acid and a neutral soil 
to which was added graduated amounts of manganese sulphate. It is 
readily apparent, therefore, that while such methods of experimentation 
are very important from an economic standpoint, they do not afford the 
desired proof to determine whether or not manganese is essential in 
the plant's economy. 
