Effects of Soil Nitrate and Carbon Availability and Soil Aeration on Nitrous Oxide Emissions in Two-Year Potato Rotations

This study examined the effects of soil carbon and nitrate availability and soil aeration on N₂O emissions in two-year potato rotations. In the potato phase of the rotations, preceding crop influenced N₂O emissions primarily through changes in soil nitrate exposure (NE) and soil carbon availability resulting from incorporation of crop residues. Fertilizer N application increased N₂O emissions as a result of increased NE values. Compacted furrow had increased denitrification rates, b1llt not N₂O emissions, compared with the hill or uncompacted furrow locations. In the rotation crop phase, N₂O emissions were controlled primarily by crop species and tillage through their effects on soil carbon availability and water-filled pore space. Choice of rotation crop can effect N₂O emissions during both the potato and rotation crop phases of two-year potato rotations. Soil carbon availability may be as important as soil nitrate availability in controlling N₂O emissions from the field.