Transpiration as a Factor in Crop Production. 53 
The results contained in Table 3 show an extreme individual 
variation of 2.35 kilograms and an average total loss of 3.4 kilo- 
grams for 1913. In 1914 the extreme variation was 1.66 kilograms, 
and the average total loss was 3.02 kilograms. No attempt has been 
made to correct the experimental data for such evaporation. 
For comparative purposes, one would conclude that an error 
exists of about 2 kilograms per plant in relative total transpiration 
when grown to maturity/while on an average the total transpira- 
tion for all plants is about 3 kilograms too high. The percentage 
of error is small and has been disregarded. 
During two months in the greenhouse in 1912, four of the 
small 4-gallon laboratory potometers described on page 50 lost 
an average of 420 grams of, water, when left uncropped. 
Table 2.— Distribution of moisture in potometers with the two 
methods of water addition used in the Nebraska experiments. 
19U. 
Water in 
Water in 
Water in 
Potometer No. 
first foot. 
second foot. 
third foot. 
Average 
Dry soil basis 
Dry soil basis 
Dry soil basis 
Per cent 
Per cent 
Per cent 
Per cent 
(1) 
(2) 
(3) 
(4) 
(5) 
WATER ADDED THRU PERFORATED SPIRAL COIL 
1 
17.4 
17.5 
16.4 
17.1 
2 
17.9 
17.7 
18.2 
17.9 
3 
17.1 
16.2 
17.2 
17.0 
4 
17.5 
17.1 
16.3 
17.0 
Average 
17.5 
17.1 
17.0 
17.2 
WATER ADDED THRU JAR AT BASE OF POTOMETER 
1 
31.7 
33.4 
34.3 
33.1 
2 
29.7 
30.6 
33.4 
31.2 
3 
31.2 
34.0 
35.2 
33.5 
4 
29.4 
33.2 
35.5 
32.7 
Average 
30.5 
32.8 
34.6 
32.6 
Table 3. — Amount of water lost from check potometers in which 
no plants were grown but otherwise treated the same as the 
cropped potometers. 
Year 
Amount of water lost 
Average 
Potometer 
No. 1 
Potometer 
No. 2 
Potometer 
No. 3 
1913 
Kilograms 
2.09 
2.70 
Kilograms 
4.44 
2.35 
Kilograms 
3.69 
4.01 
Kilograms 
3.40 
3.02 
1914 
