Soil Restoration Practices Effects on Priming Effect Intensity and Carbon Fluxes

Abstract

BackgroundThe decomposition of soil organic matter (SOM) is one of the most important processes influencing the global carbon (C) cycle, the physico-chemical characteristics of soils, the mineralization of nutrients for plant growth and soil food webs. Yet, priming effects are considered to be large enough to influence ecosystem carbon fluxes. Here we have tested the effects of soil restoration practices on priming effect and carbon fluxes.ResultOur results suggest that indirect effects are such as altered stabilization of older C associated with the increased inputs of fresh plant inputs (‘priming’) add uncertainty to the prediction of future soil C responses. Far ahead restoration influence the amount and composition of the decomposer organisms, including soil fauna, as well as the soil microbial community, by inducing up to more CO2 emission with fresh millet straw addition in fresh state than pre-decomposed one. Restoration had a very strong impact (increase by 22.7%) on basal soil organic matter mineralization but not on priming effect. The PE of non-restored site was lower than that of restored site by 14.9–22.7%; the lowest mineralization per unit carbon was recorded in the non-restored. Through the “4 per 1000” initiative, it has been very recently demonstrated that priming effect could have a noticeable impact on soil carbon sequestration. ConclusionWe have shown in our study that the degraded soil played a dominant positive role in the soil organic carbon mineralization. Our results provide solid evidence that SOC content plays a critical role in regulating apparent priming effects, with important implications for the improvement of C cycling models under global change scenarios.