4 Nebraska Agricultural Exp. Station, Research Bui. 6. 
PAGE 
Part II. The experiments 41 
Problems under investigation 41 
Methods of compiling data 41 
Methods of determining the yield and leaf -area 43 
Methods of investigation 43 
Location of experiments and maturity of plants ... 43 
Description of potometers used 43 
Potometer with coil-watering device 44 
Potometer with subirrigation- watering device . . 48 
Laboratory potometer 50 
Relative growth in field potometers and in field 50 
Distribution of moisture in soil 50 
Water loss by evaporation from the potometers 52 
Effect of size of potometer as a source of experimental 
error 54 
Effect of exposure of potometer on the growth and 
water requirements of corn 67 
Variation in results from similar potometers and the 
reduction of error by repetition 71 
The relation of climate to transpiration : 
Hourly transpiration and evaporation in relation 
to climatic factors 87 
Relative day and night transpiration and evapora- 
tion in relation to climatic factors 93 
Daily transpiration and evaporation in relation to 
climatic factors 95 
Variation in the daily transpiration rate as in- 
fluenced by the soil-moisture content 100 
Variation in weekly transpiration in relation to 
climatic factors 105 
Variation in yearly transpiration 107 
Relation of transpiration to atmospheric humidity. Ill 
Effect of previous condition of growth on transpiration. Ill 
Effect of transpiration on leaf temperature 115 
Relative rates of evaporation from equal areas of free 
water surface and leaves of growing corn plants 117 
The growing crop as a protection against water-dis- 
sipating influences 118 
Evaporation studies in corn and small-grain fields. .118 
Relative wind velocities 3 feet and 10 feet above 
the ground in a cornfield 124 
Method study with free-water-surface evaporation jars. . 125 
