RESULTS OF MEASUREMENTS. 



27 



The loss of light is found to be greater on the east than on the west 

 sides of windbreaks, and this is in part due to wider branching on the 

 east side. Part of the difference may also be ascribed to the greater 

 intensity of afternoon light. The greater amount of moisture in the 

 air in the morning has a tendency to absorb and diffuse the sunlight. 



CROP EFFECTS. 



Diagrams 7 to 13, inclusive, show graphically the results of the 

 measurements of various field crops in relation to shade, and demon- 

 strate the absolute dependence of these crops on sunlight. Table 3 

 expresses this in figures, which show the amount of light and the yield 

 of various crops growing immediately adjacent to windbreaks. 



TABLE 3. Amount of light cut off and loss to crops. 1 



[In cornfields the moisture factor is apparently eliminated.] 



1 Results of studies made in cooperation with the Nebraska Agricultural Experiment Station. 

 8 Where the per cent of damage exceeds 100 it means that the loss of crop was greater than the yield of a 

 strip whose width is equal to the height of the trees. 



If the damage to crops on the several sides of the cottonwood or 

 osage orange windbreaks is compared, it is found that the loss to the 

 crops is about proportional to and in the same area as the shadows 

 thrown by these windbreaks. The damage is greater on the north 

 than on the south side, and about equally extensive on the east and 

 west sides. Although some other factor may change this relation, 

 the shading generally does more damage to crops on the east side of 

 the windbreaks than on the west side. In spite of this, farmers 



