Nitrous oxide emissions from manured, no-till corn systems

Using dairy manure and legumes in crop rotations can reduce inorganic N inputs for corn (Zea mays L.), yet these practices also contribute to nitrous oxide (N2O) emissions. In two we investigated how different (i) organic amendments (ii) prior legume crops with broadcast influenced direct N2O emissions from silt-loam soils planted no-till corn. We measured fluxes April December years using closed vented chambers no spring residue compare fertilizer (S-UAN) liquid application methods: surface broadcasted (S-BM) injected (S-IM). Emissions were the effect of perennial forages, a green legume, or soybean (Glycine max L. Merr.) all amended manure. Nitrous greatest during 15–45 days after was compared broadcasting, cumulative larger S-IM (2.8–2.5 kg ha?1) than S-BM (1.4–0.7 S-UAN (0.3 ha?1). Cumulative yield-scaled did not differ among treatments. A ranking approach based on random forests, identified most important variable contributing both comparisons as growing degree days, indicative asynchrony termination planting use; changing environmental conditions mineralization denitrification.