Carbon and nitrogen mineralization of semi-arid shrubland soils exposed to chronic nitrogen inputs and pulses of labile carbon and nitrogen

Vourlitis, George L.; Fernandez, John S.

doi:10.1016/j.jaridenv.2015.06.007

Cited by 13 publications

(7 citation statements)

References 47 publications

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“…High rates of N leaching are thought to be a symptom of "N saturation," where N inputs exceed biological demand [Fenn et al, 2003b[Fenn et al, , 2010; however, the significantly higher NPP and N uptake of N plots implies that there is still biological demand for N. These data reinforce the notion that chaparral ecosystems, especially those recovering from fire, tend to be "leaky" such that N losses from leaching or gaseous flux can be high regardless of the N saturation state Vourlitis and Fernandez, 2012;. High N losses in semiarid shrubland soils are due to a variety of processes such as high rates of nitrification [Fenn et al, 1996;Sirulnik et al, 2007;Vourlitis et al, 2007a], pulsed resource availability that leads to temporally variable rates of microbial and/or plant N immobilization [Miller et al, 2005;Jenerette and Chatterjee, 2012;, C limitations to microbial N immobilization [Goodale et al, 2005;Vourlitis and Fernandez, 2015], high rates of water infiltration and hydraulic conductivity of xeric soils , and/or drought-induced limitations to net primary production [James and Richards, 2005].…”

Section: Effects Of N Enrichment On Postfire Successionsupporting

confidence: 72%

Impacts of chronic N input on the carbon and nitrogen storage of a postfire Mediterranean‐type shrubland

Vourlitis

Hentz

2016

JGR Biogeosciences

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Mediterranean‐type shrublands are subject to periodic fire and high levels of nitrogen (N) deposition, but little is known how chronic N deposition affects carbon (C) and N storage during succession. We conducted a long‐term experiment in Californian chaparral to test the hypothesis that chronic N enrichment would increase postfire C and N accumulation. The experimental layout consisted of a randomized design where four 10 × 10 m plots received 5 g N m−2 annually since 2003 and four 10 × 10 m plots served as controls. Aboveground and belowground C and N pools and fluxes were measured seasonally (every 3 months) for a period of 10 years. Added N rapidly increased soil extractable N pools and decreased soil pH; however, total soil C and N storage were not affected. Added N plots initially had significantly lower C and N storage than control plots, presumably because of nutrient losses from leaching and/or higher belowground C allocation. However, rates of aboveground N and C storage became significantly higher in added N plots after 4–5 years of exposure, thus increasing fuel buildup, which has implications for future fire intensity. This recovering chaparral stand is not yet “N saturated” after 10 years of chronic N input. However, N leaching continues to be higher in added N plots, indicating that postfire chaparral stands in high‐N deposition areas can be important sources of N to groundwater/aquatic systems even if productivity is stimulated by N input.

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Section: Effects Of N Enrichment On Postfire Successionsupporting

confidence: 72%

Impacts of chronic N input on the carbon and nitrogen storage of a postfire Mediterranean‐type shrubland

Vourlitis

Hentz

2016

JGR Biogeosciences

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“…China has become the world’s third largest region of N deposition [ 2 ]. Climate change alters the biogeochemical cycles of terrestrial ecosystems, such as plant primary productivity [ 3 ], microbial community structure [ 4 ], soil respiration [ 5 ], and N mineralization [ 6 ]. Recently, the effects of climate change on dissolved organic matter (DOM) have attracted extensive attention [ 7 – 8 ].…”

Section: Introductionmentioning

confidence: 99%

“…However, Chang et al found that warming decreased the concentration of DOC in the mineral soil layer [ 22 ]. N deposition might cause soil acidification [ 23 ], promote nutrient availability in the soil [ 6 ], and ultimately affect soil DOM cycling. Recently, a global study showed that the variation in DOC concentrations correlated with soil NH 4 + concentration and C/N ratio [ 24 ].…”

Section: Introductionmentioning

confidence: 99%

Effects of short-term warming and nitrogen addition on the quantity and quality of dissolved organic matter in a subtropical Cunninghamia lanceolata plantation

Yuan

Lin

et al. 2018

PLoS ONE

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Increasing temperature and nitrogen (N) deposition are two large-scale changes projected to occur over the coming decades. The effects of these changes on dissolved organic matter (DOM) are largely unknown. This study aimed to assess the effects of warming and N addition on the quantity and quality of DOM from a subtropical Cunninghamia lanceolata plantation. Between 2014 and 2016, soil solutions were collected from 0–15, 15–30, and 30–60 cm depths by using a negative pressure sampling method. The quantity and quality of DOM were measured under six different treatments. The spectra showed that the DOM of the forest soil solution mainly consisted of aromatic protein-like components, microbial degradation products, and negligible amounts of humic-like substances. Warming, N addition, and warming + N addition significantly inhibited the concentration of dissolved organic carbon (DOC) in the surface (0–15 cm) soil solution. Our results suggested that warming reduced the amount of DOM originating from microbes. The decrease in protein and carboxylic acid contents was mostly attributed to the reduction of DOC following N addition. The warming + N addition treatment showed an interactive effect rather than an additive effect. Thus, short-term warming and warming + N addition decreased the quantity of DOM and facilitated the migration of nutrients to deeper soils. Further, N addition increased the complexity of the DOM structure. Hence, the loss of soil nutrients and the rational application of N need to be considered in order to prevent the accumulation of N compounds in soil.

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“…Similarly, vegetation C:N ratios calculated as a weighted average of both woody and herbaceous vegetation were on average 29.6+2.2 and 17.8+1.9 for the control and seeded stands, respectively (2-tailed t 18 = 4.15; p < 0.001). These data suggest a potentially higher proportion of labile C in the seeded plots, which should stimulate microbial growth and/or activity (Gallardo and Schlesinger 1995;Jenerette and Chatterjee 2012), and presumably microbial N immobilization (Goodale et al 2005;Vourlitis and Fernandez 2015;Dickens and Allen 2014).…”

Section: Effects Of Post-fire Management On N Cycling and Microbial Cmentioning

confidence: 99%

Hydroseeding increases ecosystem nitrogen retention but inhibits natural vegetation regeneration after two years of chaparral post-fire recovery

Vourlitis

Griganavicius

Gordon

et al. 2017

Ecological Engineering

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Fire is a natural disturbance in many ecosystems such as semi-arid chaparral shrublands, but rates of vegetation regeneration may be slow after intense fires. Thus, land managers may resort to practices such as mulching or seeding in areas that are prone to soil erosion and nutrient loss. These practices, in particular seeding with annual grasses, are controversial because they may inhibit rates of natural vegetation regeneration, introduce exotic species, and be ineffective at soil and/or nutrient retention. We assessed how hydroseeding affected rates of chaparral vegetation regrowth and ecosystem nitrogen (N) storage during the first 2 years of post-fire recovery. We selected 3 north-facing slopes that were within 500 m of each other: one slope was unburned while the other slopes burned during the-Cocos‖ fire in May 2014 and were either hydroseeded with a mix of native grasses and suffrutescent shrubs (seeded) or left to naturally regenerate

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Carbon and nitrogen mineralization of semi-arid shrubland soils exposed to chronic nitrogen inputs and pulses of labile carbon and nitrogen

Cited by 13 publications

References 47 publications

Impacts of chronic N input on the carbon and nitrogen storage of a postfire Mediterranean‐type shrubland

Impacts of chronic N input on the carbon and nitrogen storage of a postfire Mediterranean‐type shrubland

Effects of short-term warming and nitrogen addition on the quantity and quality of dissolved organic matter in a subtropical Cunninghamia lanceolata plantation

Hydroseeding increases ecosystem nitrogen retention but inhibits natural vegetation regeneration after two years of chaparral post-fire recovery

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