Litter decomposition is fundamental for nutrient and carbon (C) cycling, playing a major role in regulating the Earth's climate system. Climate change and fertilization are expected to largely shift litter decomposition rates in terrestrial ecosystems, however, studies contextualizing the relative importance of these major global change drivers versus other key decomposition drivers such as substrate quality and ecosystem type are lacking. Herein, we used two independent field experiments in an Eastern Australian grassland (Experiment 1) and a forest (Experiment 2) to evaluate the role of (i) litter quality, (ii) nutrient addition (N, P and K in full factorial combination; Experiment 1), and (iii) a combination of N addition and irrigation (Experiment 2) in litter decomposition, substrate-induced respiration and microbial abundance. Regardless of experimental treatments, forest soils decomposed litter between 2 and 5 times faster than grassland soils. This was principally controlled by the greater ability of forest microbes to respire C-based substrates and, ultimately, by soil N availability. The experimental treatments accounted for only relatively small differences in our measured variables, ranging from 10 to 15% in the case of the irrigation-by-N-addition forest experiment to almost negligible in most of the grassland nutrient addition plots. In the latter experiment, decomposition and soil activity responses were associated with either K addition or interactions between K and other nutrients, suggesting a key role for this often-neglected soil nutrient in controlling litter decomposition. Our study provides evidence that while nutrient enrichment and/or irrigation have the potential to affect litter decomposition rates in grassland and forest ecosystems, land use change that results in loss or gain of forested area is likely to exert a much greater impact than these other two drivers.
1.Western Sydney Univ, Hawkesbury Inst Environm, Locked Bag 1797, Penrith, NSW 2751, Australia 2.Univ Rey Juan Carlos, Escuela Super Ciencias Expt & Tecnol, Dept Biol & Geol, Fis & Quim Inorgan, Mostoles 28933, Spain 3.Univ Sassari, Dept Sci Nat & Environm Resources, Via Piandanna 4, I-07100 Sassari, Italy
Recommended Citation:
Ochoa-Hueso, Raul,Delgado-Baquerizo, Manuel,King, Paul Tuan An,et al. Ecosystem type and resource quality are more important than global change drivers in regulating early stages of litter decomposition[J]. SOIL BIOLOGY & BIOCHEMISTRY,2019-01-01,129:144-152