Litter carbon and nutrient chemistry control the magnitude of soil priming effect

1. Plant litter inputs can promote the decomposition of soil organic matter (OM) through the priming effect (PE). However, whereas leaf litter chemistry has long been identified as the primary driver of litter decomposition within biomes worldwide, little is known about how litter chemical traits influence the occurrence and strength of the PE. 2. Here, we studied the effects of 15 co-occurring C3 leaf litters of contrasting chemistry on C4 soil respiration by analyzing changes in 13C natural abundance during early and later stages of litter decomposition (up to 125 days). 3. Besides an apparent PE of 16% in the first three days, soil C respiration was increased by 24% on average with leaf litter addition in the initial stage of decomposition (426 d) and by 8% at later stages (27125 d). Most interestingly, soil PE related well to initial litter chemistry and the dominant factors influencing the magnitude of the PE changed with decomposition stage. In the early stage of decomposition, ...