Increased denitrification below the root zone in the fall following a spring manure application

Indirect measurements of denitrification to 120 cm depth in a coarse textured soil in October showed higher denitrification rates following a single spring application of dairy cattle slurry than following a spring application of fertilizer. The highest denitrification rates occurred immediately above and below the water table (90 cm depth) and resulted primarily from C applied in the manure moving down through the soil profile.