First-Order Degradation of Pesticides: Theory, D.L. Nofziger

Degradation in soils is the result of a combination of chemical and, predominantly, biological events (Bollag and Liu, 1990; Wu and Nofziger, 1999). A first-order degradation model is often used to simulate the decrease of residual mass of a chemical compound in a soil system after its application (Dykaar and Kitanidis, 1996; Walker, 1974). If the first-order rate constant or half-life remains unchanged in the degradation process, the residual mass of the chemical degraded decreases exponentially with time. This program displays the changing concentration of a chemical undergoing first-order degradation for user-specified degradation rates and initial concentrations.