Harmonizing manure and mineral fertilizers can mitigate the impact of climate change on crop yields

Global population growth and climate change challenge food security severely, and adopting appropriate fertilization strategies to guarantee food production under climate change is uncertain. This research studied the crop yield and soil organic carbon (SOC) in peas-wheat-potato rotation system under four fertilization regimes (viz. unfertilized control (CK), applied mineral nitrogen and phosphorus fertilizer (NP), applied sheep manure (M), and applied NP+M (MNP)) through an 18-year field experiment combined with the DeNitrification-DeComposition biogeochemical modeling. We observed that MNP had the highest yield, the average total crop yield of pea, wheat and potato was 5784, 4735, 3240 and 1481 kg ha(-1) respectively in MNP, M, NP and CK. Manure application improved SOC significantly, it was 7.08, 7.51, 3.47 and 2.92 g kg(-1) respectively in MNP, M, NP and CK at the end of the field experiment. Under the Coupled Model Inter-comparison Project Phase 6 climate projection (2022-2100), in all four climate scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5), the yield order was MNP > M > NP > CK, and there was a significant difference in the average total yield of pea, wheat, and potato among treatments. Under future climate, the pea yields were higher than that in the historical period (2004-2021); the wheat yield in CK was similar to the historical period but it was higher in NP and M and lower in MNP than historical period. Moreover, the potato yield in MNP was slightly lower than that of the historical period but it was significantly higher in M and lower in NP and CK than historical period. Comparatively, MNP had higher yield stability and sustainability than NP, both under historical and future climate conditions. Fertilization reduced the yield response to growing-season precipitation under historical climate, while combined fertilization reduced the yield response to annual precipitation and average temperature in future climates. In addition, SOC increased in all treatments under the future climate scenarios and the effect of manure was significant, but the increase rate retarded as the climate scenario increase and time over. These results suggested that the combined application of manure and mineral fertilizer contributed to mitigating climate change's impact on crop yields.