THE RARER ELEMENTS IN SOILS AND PLANTS. Q7 
Some Organic Soil Constituents. (Bureau of Soils Bulletin 88.) Price, 10 cents. 
Occurrence and Nature of Carbonized Material in Soils. (Bureau of Soils 
Bulletin 90.) Price, 10 cents. 
Alunite as a Source of Potash. (Bureau of Soils Circular 70.) Price, 5 cents. 
Manganese as a Fertilizer. (Bureau of Soils Circular 75.) Price, 5 cents. 
Influence of a Mixture of Soluble Salts, Principally Sodium Chloride, Upon Leaf 
Structure and Transpiration of Wheat, Oats, and Barley. (Bureau of Plant 
Industry Bulletin 134.) Price, 5 cents. 
Seasonal Nitrification as Influenced by Crops and Tillage. (Bureau of Plant 
Industry Bulletin 173.) Price, 10 cents. 
WASHINGTON : GOVERNMENT PRINTING OFFICE : 19t7 
