Division 1.2 DEFINITIONS

Nitrogen transformation: is the ultimate degradation by microorganisms of nitrogen-containing organic matter, via the process of ammonification and nitrification, to the respective inorganic end-product nitrate.

EC_x (Effective Concentration): is the concentration of the test substance in soil that results in a x percent inhibition of nitrogen transformation to nitrate.

EC₅₀ (Median Effective Concentration): is the concentration of the test substance in soil that results in a 50 percent (50%) inhibition of nitrogen transformation to nitrate.