Positive feedbacks between decomposition and soil nitrogen availability along fertility gradients

Norris, Mark D.; Avis, Peter G.; Reich, Peter B.; Hobbie, Sarah E.

doi:10.1007/s11104-012-1449-3

Cited by 72 publications

(60 citation statements)

References 47 publications

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“…Magill et al [41] found that 15 years of chronic N additions increased aboveground litterfall in a red pine (Pinus resinosa) plantation. A number of other studies also reported that experimental N addition increased aboveground litter decomposition by increasing litter substrate quality, which also enhanced soil microbial activities [42][43]. Therefore, the increased CO 2 efflux from the decomposition of aboveground litter and soil organic carbon under N addition was likely caused by N-induced increasing aboveground litter input, stimulating the rate of litter decomposition and enhancing soil microbial activity in the early stage of decomposition [44].…”

Section: Effect Of Nitrogen Addition On Phytoclimate and Soil Respiramentioning

confidence: 97%

Effect of Nitrogen Addition on Soil Respiration in a Larch Plantation

Zhu

Chen

Cheng

et al. 2017

Pol. J. Environ. Stud.

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Knowledge about the impact of nitrogen (N) addition on soil respiration (Rs) is critical for understanding soil carbon (C) balance and its responses to climate change. We conducted a long-term field experiment to evaluate the response of Rs to N addition in a larch (Larix principis-rupprechtii) plantation during the growing season in northern China. We applied four N (in the form of NH 4 NO 3 ) levels, i. ) monthly starting in June 2015. The results showed that N addition -especially N2 and N3 levels -significantly stimulated Rs. N1 and N2 levels resulted in the increase of Rs in a short time, whereas the duration of N3 level can last across the whole month or at least 10 days. The results highlight the need for improving the Rs sampling interval after N addition to ensure more accurate evaluation of C emission. Soil temperature and soil moisture together explained more variations of Rs. N addition exhibited a slight increase in the sensitivity of Rs to temperature (Q 10 ), but no significant differences were found for the Q 10 among N levels.

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Section: Effect Of Nitrogen Addition On Phytoclimate and Soil Respiramentioning

confidence: 97%

Effect of Nitrogen Addition on Soil Respiration in a Larch Plantation

Zhu

Chen

Cheng

et al. 2017

Pol. J. Environ. Stud.

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“…Due to the relatively lower quality (Pregitzer et al 2002;Fan and Guo 2010), higher-order roots in mixture may serve as a competitor via inorganic N immobilization, thus decreasing the N interactions with the acid-unhydrolyzable residue of lower-order roots. It has been demonstrated that relative to low rate of N addition (54 kg N ha −1 year −1 ), high rate of N addition (170 kg N ha −1 year −1 ) can increase the N immobilization in both above-and below-ground litters (Norris et al 2013). We found that the N addition at the high rate, to some extent, increased the N immobilization in higher-order roots as compared to the low rate (Fig.…”

Section: Discussionmentioning

confidence: 54%

Effects of mixture of branch order-based roots and nitrogen addition on root decay in a subtropical pine plantation

et al. 2015

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Non-additive effects may occur when branching order-based fine roots decompose in mixture, due to their distinct chemical composition. However, these effects and how they respond to increased nitrogen (N) availability are poorly known. We conducted a 524-day field litterbag experiment to examine the potential non-additive effects of orderbased fine root decomposition and their responses to different rates of N addition in a Pinus elliottii (slash pine) plantation in China. The intact fine roots of slash pine trees were hierarchically dissected and split into two groups (lower-order roots (the first and second order roots) and higher-order roots (the third to fifth order roots)). The decomposition of these two root groups was monitored either separately or in 1:1 mixture. The non-additive effects did not occur when the two root groups decomposed in mixture. However, high rate of N addition shifted the root group interactions from additive to synergistic effects through contrasting effects on individual root group (lower-order roots). High rate of N addition retarded the decomposition of lower-order roots more in isolation than in mixture, due to the decreased binding of acid-unhydrolyzable residue to inorganic N ions in mixture. Therefore, we suggest that although stoichiometric heterogeneity holds within the branching hierarchy of fine roots, the tight coupling of N with acid-unhydrolyzable residue of root tissues may limit N use by microdecomposers, and thereby causing the additive effect. Since the mixing effect of order-based root decomposition is affected by N addition, understanding the chemical heterogeneity within fine root systems and their linkage with ambient N availability during decomposition either in isolation or in mixture may facilitate the accurate prediction of root decomposition responses to N loading.

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“…However, traditional research on these relationships has focused primarily on the aboveground plant tissues such as foliage (Hobbie 2008;Perakis et al 2012). Although a growing body of studies suggest that root-derived materials may contribute more to stabilizing soil organic matter than foliage (Rasse et al 2005;Crow et al 2009), empirical evidence for the effect of increased N availability on the afterlife of fine roots remains lacking (Conn and Day 1996;Ostertag and Hobbie 1999;Mao et al 2011;Norris et al 2013;Solly et al 2014). This, to a large extent, impedes further understanding of the responses of plant tissue decomposition to increased N availability on a broader scale, and the underlying response mechanisms.…”

Section: Introductionmentioning

confidence: 99%

“…Although both fine roots and foliage turn over rapidly, their decomposition rates may be different under ambient conditions and may even have opposing responses to N additions (Norris et al 2013). It has been reported that fine roots decompose faster than foliage in N-deficient soils (Ostertag and Hobbie 1999).…”

Section: Introductionmentioning

confidence: 99%

“…It has been reported that fine roots decompose faster than foliage in N-deficient soils (Ostertag and Hobbie 1999). In addition, a recent study found that N addition stimulates foliage decomposition, but retards root decomposition (Norris et al 2013). The differential effects of N availability on foliage and fine root decomposition can be ascribed to multiple factors, including microbial decomposer communities, decomposition environment, and tissue chemistry.…”

Section: Introductionmentioning

confidence: 99%

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Differential responses of needle and branch order-based root decay to nitrogen addition: dominant effects of acid-unhydrolyzable residue and microbial enzymes

et al. 2015

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Background and aims Both chemical differences between foliage and different orders of fine roots and their contrasting decomposing microenvironments may affect their decomposition. However, little is known about how foliage and branch order-based root decomposition responds to increased N availability and the response mechanisms behind. Methods The effects of different doses of N addition on the decomposition of needles and order-based roots of Pinus elliottii (slash pine) were monitored using the litterbag method for 524 days in a subtropical slash pine plantation in south China. The acid-unhydrolyzable residue (AUR) concentration and microbial extracellular enzymatic activities (EEA) in decomposing needles and roots were also determined. Results Our results indicate that the responses of needle and order-based root decomposition were N-dosespecific. The decomposition of both needles and lower-order roots was inhibited under the high N dose rate. The retarded decomposition of lower-order roots could be explained more by the increased binding of AUR to inorganic N ions, while the retarded decomposition of needles could be explained more by the reduced microbial EEA. Further, in contrast to lowerorder roots, N addition had no effect on the decomposition of higher-order roots. Conclusions We conclude that the decomposition of foliage and fine roots may fail to mirror each other at ambient conditions or in response to N deposition due to their contrasting decomposition microenvironments and tissue chemistry. Given the differential effects of N addition on order-based roots, our findings highlight the need to consider the tissue chemistry heterogeneity within branching fine root systems when predicting the responses of root decomposition to N loading.

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Positive feedbacks between decomposition and soil nitrogen availability along fertility gradients

Cited by 72 publications

References 47 publications

Effect of Nitrogen Addition on Soil Respiration in a Larch Plantation

Effect of Nitrogen Addition on Soil Respiration in a Larch Plantation

Effects of mixture of branch order-based roots and nitrogen addition on root decay in a subtropical pine plantation

Differential responses of needle and branch order-based root decay to nitrogen addition: dominant effects of acid-unhydrolyzable residue and microbial enzymes

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