Apr. 7.1923 Nutrition of Plants as an Electrical Phenomenon 
51 
An experiment with corn and kafir seedlings seems to throw some 
lighj: upon this subject. Six treatments in duplicate were run, 12 pans 
in all, with corn and kafir seedlings gro\\ing upon the same disks and in 
the same nutrient solutions. The disks were about 12 inches in diam¬ 
eter and were like those used in the wheat culture work except that 
the perforations were larger. The corn seedlings were planted upon 
one jfialf of the disk w^hile the kafir grew upon the other. There were 
about 50 corn to 300 kafir plants. These seedlings were placed in the 
following solutions : 
No. I. Control, distilled water. 
No. 2. 2 parts per million each N, K, and P. 
No. 3. 5 parts per million each N, K, and P. 
No. 4. 25 parts per million each N, K, and P. 
No. 5. 50 parts per million each N, K, and P. 
No. 6. 100 parts per million each N, K, and P. 
They were allowed to grow for 17 days. In each pan, 2,500 cc. of solu¬ 
tion were used and the experiments were run in duplicate. For con¬ 
venience the average of the duplicates is given in Table VIII. 
TABr:iS VIII .—Nitrogen absorbed by corn and kafir seedlings competing in nutrient 
solutions of various strengths 
No. 
Strength of solution. 
Total N added. 
Nitrogen absorbed. 
By com. 
By kafir. 
Gm. 
Gm. 
Gm. 
1 
Water. 
0 
0 
0 
2 
2 p. p. m. 
0.0450 
0.0466 
^ 0.0073 
3 
5 p. p. m... 
.1125 
.1094 
.0091 
4 
25 P. P- m. 
■ 5625 
•^475 
^ .0180 
5 
50 p. p. m. 
1.1250 
•3344 
6 
100 p. p. m.... 
2.2500 
.3821 
(') 
1 noss. » Poor plants. 
From this one experiment the indications are that when com and kafir 
are placed in keen competition as in solutions containing 2 and 5 parts 
per million the corn may get all the nitrogen and the kafir little or none. 
An actual loss of nitrogen is noticed in the kafir in the two lowest concen¬ 
trations, which might be explained by the exudation of this element into 
the solution or by the probable error of the experiment. The solutions 
were well mixed and not stirred while the plants drew out the nitrogen: 
In places the kafir roots were 6 inches away from the com and in contact 
with the nitrates in the solution but, the kafir being a sluggish feeder while 
the com was a vigorous feeder, the nitrates seem to have gone to the 
corn and not to the kafir. The absorption of the small quantity of 
nitrates was so rapid that it does not seem reasonable to assume that 
diffusion carried it all to the com side of the pan. The difference is so 
marked that one must admit that in this case the kafir had no chance 
in competition with com and that the nitrogen must have moved as far 
as 6 inches in a very short time. If, in a soil at optimum moisture con¬ 
tent, the plant is dependent upon the soil grains that touch its roots, 
this competition is rather difficult to conceive of. Practically speaking, 
the absorbing surface of the roots of different plants would hardly touch 
the same soil grains often enough to be of serious consideration. 
