Intercropping-driven effects on soil organic carbon mineralization and its temperature sensitivity are associated with soil C-N-P stoichiometry and carbon-acquiring microorganisms and enzymes

By cultivating diverse plants on a same land, intercropping can enhance soil organic carbon (SOC) sequestration and crop production efficiency. However, the impact of different intercropping practice on SOC mineralization and its stability under global climate change remains limited. Herein, an eight-year field-based experiment with maize monoculture and four intercropping patterns was employed to investigate the intercropping-induced change in the SOC mineralization rate and its temperature sensitivity (Q 10 ). The carbon–nitrogen-phosphorus (C-N-P) stoichiometry of soil and microbiome, C-acquiring enzyme activities, and the abundances of 15 functional genes relating to SOC mineralization were employed to identify their relationships with SOC mineralization rate and its Q 10 . The results showed that the responses of SOC mineralization rate and its Q 10 to intercropping practice varied based on the intercropping patterns and maize growth stages. Compared to monoculture, the maize intercropping with gingelly and sweet potatoes consistently exhibited lower Q 10 across maize four growth stages, the maize-peanut system presented lower Q 10 during the elongation, flowering and mature stages, and the maize-soybean system showed lower value specifically during the mature stage. Maize intercropping, particularly with soybean and sweet potato, significantly increased most of the C-mineralization gene abundance and C-acquiring enzyme activity we studied. In addition, most the C-acquiring gene abundance and enzyme activity we studied as well as the C-N-P contents and stoichiometic ratios of soil and microbial biomass were significantly related to the SOC mineralization rate and its Q 10 . These findings elucidated the benefits of maize-based intercropping in SOC mineralization and its stability, which was largely associated with the response of soil C-N-P stoichiometry and C-acquiring microorganisms and enzymes to intercropping patterns and plant development. This study suggests that soil C pools can be stabilized while enhancing food production through intercropping under climate change.