356 SOIL CONDITIONS AND PLANT GROWTH 



Methods of Sand and Soil Cultures. — See Hellriegel (i3o<^) and — 

 Sand, McCall, A. G., Journ. Amer. Soc. Agron., 191 5, 7> 249- 

 282 ; Soil Sci , 191 6, 2, 207-253; Journ. Amer. Soc. Agron., 19 18, 

 10, 127-134. Hoagland, D. K., Journ. Ag. J?es., 1919, 18, 177. 



Comparison of Sand and Water Cultures., Hoagland, D. 1^., Journ. 

 Ag. Res., 1 9 19, 18, II. 



