CONTENTS. 7 
Effect of climatic factors 0:1 the water requirement — Continued. Page. 
Effect of the carbon-dioxid content of the air on the water requirement. . . 65 
S< irauer'a experiments 65 
Conclusions 66 
Effect of parasites on the water requirement GG 
Wimmer's experiments 6G 
Other factors influencing the water requirement 67 
Effect of relative leaf area on the water requirement 67 
Montgomery's experiments G7 
Effect of frequent cutting on the water requirement 68 
Yon Seelhorst's experiments (58 
Effect of defoliation on the water requirement 69 
Sorauer's experiments 69 
Effect of the amount of growth or number of plants per unit of soil mass on 
the water requirement 70 
Von Seelhorst and Biinger's experiments 70 
Effect of the age of the plant on the water requirement 70 
Von Seelhorst's experiments 70 
Eest's experiments 71 
Von Seelhorst's later experiments 72 
Conclusions 72 
Water requirement of different kinds of plants 72 
Woodward's experiments 72 
Lawes's experiments 73 
Wollny's experiments 73 
Sorauer's experiments 74 
Hellriegel's experiments 74 
King's experiments 76 
Von Seelhorst's experiments 77 
Widtsoe's experiments 78 
Leather's experiments •_ 78 
Briggs and Shantz's experiments 80 
Conclusions 82 
Determination of the water requirement of crops under field conditions 84 
Crops grown with irrigation 84 
Widtsoe's experiments 84 
Crops grown without irrigation 85 
Leather's experiments 85 
Briggs and Shantz's experiments 87 
Conclusions 88 
Summary 88 
Literature cited 93 
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