188 



EXPERIMENT STATION. 



[Jan. 



the loose subsoil, and the rattlebox and white clover showed 

 greater capacity for adaptability to tamped soil than the 

 lettuce. 



Lettuce is remarkably susceptible to lack of soil aeration, 

 as is shown by the many experiments we have made with this 

 plant. The following table shows the effect of soil texture 

 upon the germination and growth of lettuce. The boxes 

 employed in this experiment were eight inches square, and 

 each was nearly filled with carefully sifted coal ashes, con- 

 taining particles corresponding to the sizes given in the table. 

 Each box was weighed and watered daily, and the amount of 

 water applied was such that the degree of saturation was 

 equal to one-half the water-retaining capacity. 



Influe7ice of Soil Texture on the Oermination of Lettuce Seeds and 

 Growth of Seedlings. 



Size of 



Particles 



(Millimeters). 



Per Cent, of 

 Germination. 



Average Weight 

 of Seedlings 

 (Milligrams) . 



Box 1, 

 Box 2, 

 Box 3, 

 Box 4, 

 Box 5, 



2-1 



1-.5 

 ..5-. 25 

 .2.i-.l 

 .l-.OOOl 



54.2 

 38.0 

 24.8 

 33.0 

 14.2 



40-60 

 80-84 

 59.99. 

 41.45 

 19.25 



The preceding table includes the results of three experi- 

 ments, in which 3,000 seeds were employed. The highest 

 percentage of germination is given by the seeds sown in 

 ashes containing particles having a size of 2-1 millimeters ; 

 while the largest average weight of the seedlings is shown by 

 those which were grown in ashes containing particles having 

 a diameter of 1-.5 millimeters. In the case of some experi- 

 ments in similar boxes with sand the highest percentage 

 of germination took place in the particles ranging from 

 .5 to .25 millimeters; and the largest average weight of 

 seedlings was given by the particles ranging in size from 

 1 to .5 millimeters, or the same as in the experiment with 

 ashes. It should be pointed out that important differences 

 exist between coal ashes and sand in respect to absorption of 



