Objectives We studied the impacts of soil and water conservation measurements on greenhouse gas emissions from red slope farmland and their comprehensive greenhouse effect, to provide theoretical support for choosing efficient mitigation technology while maintaining high crop yields.

Methods A soil and water conservation experiment was conducted in a slope farmlands in Jiangxi Province, where the cropping system is peanut-rapeseed rotation. The treatments included conventional tillage with hedgerows (HT), conventional tillage with rice straw mulching during peanut season (MT), and no-tillage (NT), as well as an merely conventional tillage control (CT). The static chamber-gas chromatography method was applied for monitoring in-situ CO₂, CH₄, and N₂O emission fluxes in a year period. The crop yield were recorded, and the global warming potential (GWP) and greenhouse gas intensity (GHGI) were calculated, the influencing factors were proposed using correlation and redundancy analysis.

Results Compared with CT, MT treatment reduced the cumulative N₂O emissions by 13.1%, while NT and HT treatments increased them by 28.5% and 19.7%, respectively; The NT treatment significantly decreased the cumulative CO₂ emissions by 10.4%, whereas the HT and MT treatments increased them by 17.9% and 10.1%, respectively, with the majority of the increase attributed to CO₂ emissions during the rape season; All three treatments showed weak CH₄ sink. Redundancy analysis results indicated that air temperature, soil water and nitrate nitrogen content were the key factors determining the emissions of the three greenhouse gases. Under a 100-year CO₂-equivalent time scale, the annual GWP of the HT and MT treatments increased by 18.1% and 9.5%, respectively, compared with the CT treatment, while the NT treatment decreased it by 9.4%. The annual GWP was mainly contributed by CO₂ emissions, followed by N₂O emissions, while soil CH₄ emissions had a negative contribution. The HT treatment showed a significantly higher peanut and annual yield than the other treatments. Although HT and MT were recorded higher GWP than CT and NT, HT had similar GHGI due to higher crop yield, while MT had significantly higher GHGI.

Conclusions The soil of peanut-rapeseed rotation farmland on red-slop farmland serves as a source of N₂O and CO₂ emissions, and a weak sink for NH₄. Due to high temperature and elevated soil moisture, the greenhouse gas emission intensity during the peanut season is greater than that during the rapeseed season, making it the primary period for greenhouse gas emissions. The planting of hedgerows and straw mulching increase CO₂ emissions, resulting in a significant higher global warming potential, compared to conventional tillage. However, since planting hedgerows enhances peanut yield, it subsequently reduced the comprehensive greenhouse emission intensity. Considering the crop yield and environmental effects, both planting hedgerows and no tillage represent a relatively ideal soil and water conservation measures for the red-slop farmlands.