Crop rotations combined with nitrogen fertilizer management reduce greenhouse gas emissions during potato phase without impacting potato yield

This study evaluated the impacts of crop rotations and nitrogen (N) fertilizer management on potato yield and greenhouse gas (GHG: N 2 O, CO 2 , and CH 4 ) emissions during the potato ( Solanum tuberosum L.) phase. Three rotation systems were compared: (i) barley ( Hordeum vulgare L.) underseeded with a forage legume–forage legume–potatoes (B–FL–P); (ii) corn ( Zea mays L.)–sorghum Sudan grass ( Sorghum bicolor × sorghum bicolor var. Sudanese)–potatoes (C–SS–P); and (iii) soybean ( Glycine max)–brown mustard ( Brassica juncea L.)–potatoes (S–BM–P). An experimental design established at two adjacent sites in 2015 was used. In 2024 at site A, during the potato phase, the main plot was split into two to compare urea at 160 kg N ha −1 with 120 kg N ha −1 as super urea (Super U), whereas urea at 160 kg N ha −1 was compared with reduced urea at 120 kg N ha −1 at site B. At both sites, reducing N rates by 25% did not impact potato marketable yield. At site A, B–FL–P had significantly higher N 2 O emissions than other rotations. Super U at a reduced rate had 5.7 times lower total N 2 O emissions than urea at the recommended rate. At site B, S–BM–P had 66% lower total N 2 O emissions than B–FL–P and 50% lower than C–SS–P. Current N recommendations could be reduced without impacting potato yields with Super U being more effective in mitigating N 2 O than urea. Correlations between GHG with soil moisture and temperature and with mineral N are discussed.