Ammonia and greenhouse gas emissions from land application of solid beef manure and urea to corn fields in south central Nebraska

A two-year study was conducted to quantify ammonia (NH3) and greenhouse gas (GHG) emissions following land application of manure and commercial fertilizer to corn fields. Four treatments were evaluated: commercial fertilizer (CF), solid beef manure (SM), solid beef manure with corn stover bedding (BM), and no fertilizer (NF). The CF, SM, and BM treatments were applied in the fall to meet corn N demand. Air samples were measured following land application and at two-week intervals from planting to harvest. Sixteen plots were used with four replications per treatment. Average daily NH3 flux were greater from plots that received the CF treatment (2436 µg m^-2 hr^-1) compared to plots that that had NF (1875 µg m^-2 hr^-1), SM (1857 µg m^-2 hr^-1) and BM (1850 µg m^-2 hr^-1) treatments applied. No differences were detected in daily CH4, CO2, or N2O flux due to fertilizer treatment, but all gases measured varied significantly between growing seasons. Cumulative NH3 emissions were higher for CF plots (214.3 kg ha^-1) than SM (147.6 kg ha^-1), BM (148.8 kg ha^-1), and NF (151.5 kg ha^-1). Cumulative CO2 emissions were higher for SM (5.3 Mg ha^-1) and BM (4.9 Mg ha^-1) plots compared to CF (2.6 Mg ha^-1) and NF (2.5 Mg ha^-1) treated plots. The significant differences between emissions from year to year emphasizes the need for long-term studies to better understand gaseous emissions from fertilizer application. With similar emissions from all fertilizer treatments, producers can consider using manure as a nitrogen source to reduce costs associated with purchasing commercial fertilizer.