Mass loss and nutrient dynamics during litter decomposition in response to warming and nitrogen addition in a desert steppe

Abstract

Plant litter decomposition has been studied extensively in the context of both warming and increased atmospheric nitrogen deposition. However, the temporal patterns of mass loss and nutrient release in response to warming and nitrogen addition remain unclear. A 2-year decomposition experiment aimed to examine the effects of warming and nitrogen addition on decomposition rate, and nitrogen and phosphorus dynamics. The effects of warming and nitrogen addition on decomposition of litter of Stipa breviflora, a dominant species in a desert steppe of northern China, were studied. Warming and nitrogen addition significantly enhanced litter mass loss by 10% and 16%, respectively, and moreover promoted nitrogen and phosphorus release from the litter in the first year of decomposition, followed by an immobilization period. The interactive effects of warming and nitrogen addition on mass loss, nitrogen and phosphorus concentrations of litter were also found during the decomposition. This study indicates that warming and nitrogen addition increased litter mass loss through altering litter quality. These findings highlight that interactions between climate change and other global change factors could be highly important in driving decomposition responses.

Responses of Litter Decomposition and Nutrient Dynamics to Nitrogen Addition in Temperate Shrublands of North China

“…However, our results differed from those of Han et al (2014) , who found that nitrogen deposition inhibited temperate forest litter decomposition in a Quercus liaotungensis forest that is subject to chronically high levels of ambient N deposition. Moreover, Ren et al (2018) found that nitrogen addition significantly promoted the decomposition of Stipa breviflora litter in a desert steppe.…”

“…Exogenous N also increases enzyme activity ( Keeler et al, 2009 ) or contributes to the production of high-quality litters ( Suding et al, 2005 ), all of which lead to an increase in decomposition. Ren et al (2018) found that simulated N deposition stimulated litter decomposition in a desert steppe under nutrient-deficient conditions. Thus, we proposed the following hypotheses: (1) N addition would stimulate litter mass loss in the temperate shrublands of northern China, (2) N addition would inhibit litter nutrient release during the early decomposition stage, and (3) the decomposition rate of high-quality litters is faster than that of low-quality litters.…”

“…The decomposition rate and nutrient release pattern are dependent on abiotic factors (e.g., climate conditions and soil physical and chemical properties) and biotic factors (e.g., litter quality and microbial community composition) ( Prescott, 2005 ; Yu et al, 2015 ; Song et al, 2018 ; Lin et al, 2019 ). At the global scale, plant litter decomposition is controlled by climate and litter quality ( Sun et al, 2004 ; Cornwell et al, 2008 ; Zhang et al, 2008 ); at the local scale, it is regulated by litter chemical properties and site soil conditions ( Zhang et al, 2016 ; Zhu W. Y. et al, 2016 ; Ren et al, 2018 ).…”

“…Numerous studies in various ecosystems have been conducted to explore the effects of N deposition on litter decomposition ( Tu et al, 2014 ; Yu et al, 2015 ; Zhu W. Y. et al, 2016 ; Zhu X. M. et al, 2016 ; Wang et al, 2017 ; Ren et al, 2018 ; Yan et al, 2019 ; Pei et al, 2020 ; Zhang et al, 2020 ). However, the responses of litter decomposition to N addition have varied considerably, from positive ( Downs et al, 1996 ; Allison et al, 2009 ; Hobbie et al, 2012 ; Ren et al, 2018 ) or neutral ( Prescott, 1995 ; Hobbie and Vitouesk, 2000 ) to negative ( Micks et al, 2004 ; Hobbie et al, 2012 ; Zhou et al, 2017 ). Some chemical, biological, and biochemical hypotheses have been proposed to explain the possible mechanisms of the different effects of N deposition on litter decomposition, but the effects of N input on litter decomposition are still poorly understood ( Carreiro et al, 2000 ; Knorr et al, 2005 ; Liu et al, 2010 ; Prescott, 2010 ; Sinsabaugh, 2010 ; Lu et al, 2014 ).…”

“…Numerous studies in various ecosystems have been conducted to explore the effects of N deposition on litter decomposition (Tu et al, 2014;Yu et al, 2015;Zhu W. Y. et al, 2016;Zhu X. M. et al, 2016;Wang et al, 2017;Ren et al, 2018;Yan et al, 2019;Pei et al, 2020;Zhang et al, 2020). However, the responses of litter decomposition to N addition have varied considerably, from positive (Downs et al, 1996;Allison et al, 2009;Hobbie et al, 2012;Ren et al, 2018) or neutral (Prescott, 1995;Hobbie and Vitouesk, 2000) to negative (Micks et al, 2004;Hobbie et al, 2012;Zhou et al, 2017).…”