Abstract
In the tropics of South China, climate change induced more rainfall events in the wet season in the last decades. Moreover, there will be more frequently spring drought in the future. However, knowledge on how litter decomposition rate would respond to these seasonal precipitation changes is still limited. In the present study, we conducted a precipitation manipulation experiment in a tropical forest. First, we applied a 60% rainfall exclusion in April and May to defer the onset of wet season and added the same amount of water in October and November to mimic a deferred wet season (DW); second, we increased as much as 25% mean annual precipitation into plots in July and August to simulate a wetter wet season (WW). Five single‐species litters, with their carbon to nitrogen ratio ranged from 27 to 49, and a mixed litter were used to explore how the precipitation change treatments would affect litter decomposition rate. The interaction between precipitation changes and litter species was not significant. The DW treatment marginally accelerated litter decomposition across six litter types. Detailed analysis showed that DW increased litter decomposition rate in the periods of January to March and October to December, when soil moisture was increased by the water addition in the dry season. In contrast, WW did not significantly affect litter decomposition rate, which was consistent with the unchanged soil moisture pattern. In conclusion, the study indicated that regardless of litter types or litter quality, the projected deferred wet season would increase litter decomposition rate, whereas the wetter wet season would not affect litter decomposition rate in the tropical forests. This study improves our knowledge of how tropical forest carbon cycling in response to precipitation change.
Highlights
Litter decomposition is a key process of turning carbon (C) and nutrients from organic to inorganic state, which could be utilized by plants and microbes in terrestrial ecosystems
A large number of studies have revealed that precipitation is among the most important factors regulating litter decomposition rate in terrestrial ecosystems (Aerts, 1997; Taylor et al, 2017; Wieder, Cleveland, & Townsend, 2009)
Two‐way ANOVA only detected a marginally significant difference among treatments (p = .078), the multiple comparisons indicated that deferred wet season (DW) significantly increased k (p = .028), whereas wetter wet season (WW) tended to TA B L E 1 Initial organic carbon (C) content, total nitrogen (N) content, and C:N ratio for litters of Symplocos chunii (SC), Aphanamixis polystachya (AP), Acacia crassicarpa (AC), Schefflera octophylla (SO), Carallia brachiate (CB), and mixed litter (Mix)
Summary
Litter decomposition is a key process of turning carbon (C) and nutrients from organic to inorganic state, which could be utilized by plants and microbes in terrestrial ecosystems. A large number of studies have revealed that precipitation is among the most important factors regulating litter decomposition rate in terrestrial ecosystems (Aerts, 1997; Taylor et al, 2017; Wieder, Cleveland, & Townsend, 2009). There is still limited report on how seasonal precipitation change would affect litter decomposition rate in tropical forests. Litter traits, such as C:N ratio, strongly regulate litter decomposition rate (Aerts, 1997; Chapin, Matson, & Vitousek, 2011; Cornwell et al, 2008) and its response to environmental changes (Knorr, Frey, & Curtis, 2005; Liu et al, 2017). We hypothesized that the response of litter decomposition rate to the precipitation change treatments would be species‐specific as these litters differed in litter quality
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