Transpiration as a Factor in Crop Production. 
159 
Aside from a lack of thrift during the last three years, the 
reduced yield might be partially explained by the fact that a 
smaller variety (Pride of the North) was grown than the Hogue's 
Yellow Dent variety of the first year. A comparison of these 
two corns was made in the variety test of 1914. The Hogue's 
Yellow Dent corn produced 25 per cent greater dry matter. 
However, in this fertility experiment, the average yield of dry 
matter for the six degrees of fertility was 304.9 grams in 1911 
and only 169.0 grams in 1914. It might be stated in this con- 
nection that in all the experiments reported in this bulletin, 
with this one exception, the potometers were filled with new soil 
every year. In spite of the abnormal condition of the plants in 
this experiment, the data show a very marked residual effect of 
manure on production for four years. The cause of this deterio- 
ration of soil productivity from prolonged confinement in cans 
will be further investigated. 
INFLUENCE OF ACCLIMATIZATION, VARIETY, AND KIND OF 
CROP UPON THE TRANSPIRATION RELATIONSHIPS. 1 
In 1914 a comparative study was made of the use of water 
by corn differing in acclimatization, growth habits, erectness of 
leaves, and alleged drouth resistance. Sorghums and wild sun- 
flowers were also compared with corn. The ears harvested from 
the different corn varieties are shown in Figure 21. 
The plants were grown singly in potometers 16 by 36 inches in 
size, containing 248 pounds of fertile, moisture-free surface soil, 
and having an application of 1.75 pounds of well-rotted moisture- 
free sheep manure mixed in with the upper 10 inches of soil. 
A constant and uniform amount of moisture was available to all 
plants. The results are given in detail in Table 67 and are sum- 
marized in Table 68. 
ACCLIMATIZATIONS 
Two varieties of corn (Rocky Mountain Dent and Wood's 
White Dent), acclimatized to the humid soil and climate of New 
York, were compared with two varieties (Calico from North 
Platte, Nebr., and Martens' White Dent from Chadron, Nebr.) 
1 References concerning the relation of transpiration to kind of crop 
and variety: Briggs and Shantz (1913, 1914), Hellriegel (1883), King (1892, 
1893, 1894, and 1895), Lawes (1850), Leather (1910, 1911), Seelhorst (1906, 
1908), Sorauer (1883), Thorn (1913), Thorn and Holtz (1914), Widtsoe (1909), 
Widtsoe and Merrill (1902), Willard and Humbert (1913), and Wollny (1877). 
2 The Rocky Mountain Dent, Wood's White Dent, and Martens' White 
Dent corn were secured from C. P. Hartley of the United States Department of 
Agriculture. The Calico corn was obtained from W. P. Snyder, Superintendent 
of the North Platte Experimental Substation, North Platte, Nebr. 
