20 



EFFECTS OF ARTIFICIAL SHADING ON PLANT GROWTH. 



At the end of the experiment it was evident that corn was the least 

 tolerant of shade of any of the plants used, and a reduction of light to 

 n/2 caused a decided reduction in growth. Figure 11 shows the 

 relative size of the corn at the end of the experiment. 



In corn, as in the other plants, the differences due to differences in 

 light intensity were much greater than those produced by the varia- 

 tions in other factors. 



Fig. 11.— Relative sizes of corn plants 50 days after germination. The numbers correspond to those of the 

 shades and the letters indicate the two beds in the experiment. (Traced from photograph.) 



GENERAL CONDITION OF THE PLANTS AT THE END OF 30 DAYS. 



The relative green weights based upon the average weight per plant 

 at the end of 30 days under the different light intensities is shown in 

 Table IV. The results for beds A and B show clearly that the growth 

 was uniformly better in full light at this early period of the experi- 

 ments. While the weights of some of the plants grown in the shades 

 were above the weights of those grown in normal light, this was the 

 exception rather than the rule. At the end of 30 days many of the 

 plants were still growing even in the deeper shades, and at this time 

 the green weights of the plants in most cases showed a gradual 

 decrease from those in full light to those in n/93 light. 



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