A METHOD FOR THE RENEWAL OF PLANT NUTRIENTS 



IN SAND CULTURES. 



A. G. McCall. 



The recent publications of Tottingham''' and of Shivef have 

 suggested the desirabihty and importance of having some 

 method by which the effect of different nutrient solutions upon 

 plant growth might be studied in the presence of some solid 

 substance similar to the soil, but at the same time furnishing 

 fewer chemical and biological complications. Acting upon this 

 suggestion the writer has devised a method by which seedling 

 may be grown in sand and the nutrient solution renewed or 

 modified almost as readily as in water cultures. In duplicating 

 in sand some of Shive's w^ork with wheat seedlings in solution 

 cultures, use was made of graniteware pots approximately 

 12 X 12 centimeters inside, tapering slightly at the base and 

 having a wide projecting rim at the top and a capacity of 1500 

 grams of dry quartz sand when filled to within about three 

 centimeters of the top. To provide for the removal of the 

 solution a small lead tube was soldered into the side as near the 

 bottom as possible. The soldered joint and the lead tube was 

 covered with paraffin to guard against lead poisoning and the 

 outlet closed by means of a short length of rubber tubing pro- 

 vided with a pinch cock. The description of the method given 

 in the following paragraphs includes the details of manipulations 

 from the starting of the seedlings to the harvesting of the 

 plants. The seed is soaked in water and the seedlings grown in 

 the manner described by Tottingham|, to a height of about 

 three or four centimeters, when they are ready to be transferred 

 to the sand cultures. While the seed is being germinated 1500 

 grams of dry quartz sand (previously washed several times with 

 distilled water) is weighed into the pot, the outlet at the bottom 

 of the pot being screened on the inside by means of a plug of 

 glass wool inserted before the pot is filled. With the pinch cock 

 closed distilled water is now added to the pot until the sand is 

 completely saturated, after which the pinch cock is opened and 

 the surplus water is allowed to drain out through the tube at 



*A Qualitative Chemical and Physiological Study of Nutrient Solutions for 

 Plant Cultures. Physiological Researches Vol. I, No. 4, May, 1914. 



fA Three-Salt Nutrient Solution for Plants. Amer. Journal of Botany, 

 4:157-160, April 1915. 



JTottingham. p. 176. 



lOI 



