SOIL DEFICIENCIES 249 



sides and top, for protection against heat, storm, and insect pests. 

 Wire basket experiments 1 are made in baskets of wire netting, 

 about 3 inches in diameter and 3 inches high, filled with about 200 

 grams soil, and dipped into melted paraffin. The surface of the 

 soil is covered with paraffined paper, excepting for an opening to 

 admit the seedlings. The pots are weighed daily, and the loss 

 of water restored. The plants are grown for about three weeks. 



Fig- 59- Construction of wire baskets. Bureau of Soils, U. S. D. A. 



Since air is excluded from the soil and since the seedlings develop 

 for the most part from the material in the seed, these experiments 

 are more remote from field experiments than ordinary pot experi- 

 ments ; still greater caution, therefore, should be exercised in 

 interpreting the results. According to the work of the Rhode 

 Island Station, 2 this method does not give the same results at 

 different times, and the results do not agree with those obtained in 

 field practice. 



1 Whitney, Farmers Bulletin No. 257. 

 - Bulletin 131. 

 17 



