LETTER OF TRANSMITTAL. 



U. S. Department of Agriculture, 



Bureau of Plant Industry, 



Office of the Chief, 

 Washington, D. C, December 4, 1912. 

 Sir: I have the honor to transmit herewith a manuscript entitled 

 "The Effects of Artificial Shading on Plant Growth in Louisiana," 

 by Dr. H. L. Shantz, Physiologist, Alkali and Drought Resistant 

 Plant Investigations, and to recommend its publication as Bulletin 

 Xo. 279 of this Bureau. 



This manuscript describes experiments with various crop plants 

 which were grown under artificial shades of different degrees of 

 density, the purpose being to determine the effect of diminished 

 light intensity upon the growth of plants. In nearly every case a 

 moderate reduction in the intensity of the light resulted in an increased 

 growth as compared with plants of the same species growing in the 

 open. It was also observed that in the case of lettuce the quality 

 was improved by a moderate degree of shade. These results are 

 obviously significant in relation to plant growth in the arid regions, 

 where the light is normally much more intense than in Louisiana. 

 Cooperative experiments of a similar nature are now in progress 

 in Colorado, the object being to determine the importance of light as 

 a factor in the physiology of drought resistance. 



The experiments here described were conducted by Dr. Shantz 

 at the L^niversity of Louisiana while occupying the chair of botany 

 and bacteriology at that institution. 



Respectfully, B. T. Galloway, 



Chief of Bureau. 

 Hon. James Wilson, 



Secretary of Agriculture. 



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