Nitrogen Transformations During Continuous Leaching

Abstract

Abstract The simultaneous occurrence of nitrification, denitrification, and N movement was investigated in a soil column during continuous unsaturated leaching. During a continuous application of an NH 4 Cl solution, analyses were made of the soil solution with soil depth and time for N as NH 4 + , NO 2 ‐ and NO 3 ‐ ; and of the soil atmosphere for O 2 , CO 2 , N 2 O, and N 2 . The use of 15 N permitted direct measurement and quantification of nitrification and denitrification, as well as the transport of N in the liquid and gaseous phases. Solutions to the appropriate equations using measured reaction rate coefficients, pore‐water velocities, and diffusion co‐efficients adequately described the steady state NH 4 + ‐N and NO 3 ‐ ‐N concentration distribution in the soil profile. Equations were also used to stoichiometrically account for the various interacting species in the N transformations.