POTENTIAL FOR NITRATE-N LOSS IN CENTRAL ALBERTA SOILS

Incubation experiments were conducted to determine the influence of soil type, soil depth and tillage-straw treatment on the capacity for NO3-N loss under anaerobic incubation. In Experiment 1 with 14 cultivated surface soil samples, there were substantial NO3-N losses in all soils regardless of the total organic carbon content. The total organic content of these soils ranged from 21 to 55 g C kg-1. Experiment 2 showed that the rate of NO3-N loss decreased with depth of soil, but when glucose was added the rate of NO3-N loss increased markedly and all of the added NO3-N disappeared within less than a week. In Experiment 3, the soil under zero tillage where straw was retained gave slightly higher rate of NO3-N loss than the soil from conventional tillage treatment.