Nitrous oxide (N 2 O) is a potent greenhouse gas (GHG) whose atmospheric concentration continues to rise, largely driven by nitrogen (N) inputs to agricultural soils. Over the past three decades, research on soil N 2 O emissions has advanced substantially, yet key uncertainties still constrain mitigation efforts. Here, we synthesize developments in measurement techniques, process understanding, microbial ecology, and modelling...

Models project that climate change is increasing the frequency of severe storm events such as hurricanes. Hurricanes are an important driver of ecosystem structure and function in tropical coastal and island regions and thus impact tropical forest carbon (C) cycling. We used the DayCent model to explore the effects of increased hurricane frequency on humid tropical forest C stocks and fluxes at decadal and centennial timescale...

Composting organic matter can lower the global warming potential of food and agricultural waste and provide a nutrient-rich soil amendment. Compost applications generally increase net primary production (NPP) and soil water-holding capacity and may stimulate soil carbon (C) sequestration. Questions remain regarding the effects of compost nitrogen (N) concentrations and application rates on soil C and greenhouse gas dynamics. I...

Increasing hurricane frequency and intensity with climate change is likely to affect soil organic carbon (C) stocks in tropical forests. We examined the cycling of C between soil pools and with depth at the Luquillo Experimental Forest in Puerto Rico in soils over a 30‐year period that spanned repeated hurricanes. We used a nonlinear matrix model of soil C pools and fluxes (“soilR”) and constrained the parameters with soil and...

The ongoing climate crisis merits an urgent need to devise management approaches and new technologies to reduce atmospheric greenhouse gas concentrations (GHG) in the near term. However, each year that GHG concentrations continue to rise, pressure mounts to develop and deploy atmospheric CO 2 removal pathways as a complement to, and not replacement for, emissions reductions. Soil carbon sequestration (SCS) practices in working...

Agricultural peatlands are estimated to emit approximately one third of global greenhouse gas (GHG) emissions from croplands, but the temporal dynamics and controls of these emissions are poorly understood, particularly for nitrous oxide (N 2 O). We used cavity ring‐down spectroscopy and automated chambers in a drained agricultural peatland to measure over 70,000 individual N 2 O, methane (CH 4 ), and carbon dioxide (CO 2 ) fl...

Globally, soils store two to three times as much carbon as currently resides in the atmosphere, and it is critical to understand how soil greenhouse gas (GHG) emissions and uptake will respond to ongoing climate change. In particular, the soil‐to‐atmosphere CO 2 flux, commonly though imprecisely termed soil respiration ( R S ), is one of the largest carbon fluxes in the Earth system. An increasing number of high‐frequency R S...

Carbon (C)‐rich wetland soils are often drained for agriculture due to their capacity to support high net primary productivity. Increased drainage is expected this century to meet the agricultural demands of a growing population. Wetland drainage can result in large soil C losses and the concentration of residual soil minerals such as iron (Fe) and aluminum (Al). In upland soils, reactive Fe and Al minerals can contribute to s...

Reflooding formerly drained peatlands has been proposed as a means to reduce losses of organic matter and sequester soil carbon for climate change mitigation, but a renewal of high methane emissions has been reported for these ecosystems, offsetting mitigation potential. Our ability to interpret observed methane fluxes in reflooded peatlands and make predictions about future flux trends is limited due to a lack of detailed stu...

Humid tropical forests are among the most productive ecosystems globally, yet they often occur on soils with high phosphorus (P) sorption capacity, lowering P availability to biota. Short‐term anoxic events are thought to release sorbed P and enhance its acquisition by soil microbes. However, the actual effects of anoxic conditions on microbial P acquisition in humid tropical forest soils are surprisingly poorly studied. We us...

Invasive plants can increase soil nitrogen (N) pools and accelerate soil N cycling rates, but their effect on gross N cycling and nitrous oxide (N 2 O) emissions has rarely been studied. We hypothesized that perennial pepperweed ( Lepidium latifolium ) invasion would increase rates of N cycling and gaseous N loss, thereby depleting ecosystem N and causing a negative feedback on invasion. We measured a suite of gross N cycling...

Fine root decomposition constitutes a critical yet poorly understood flux of carbon and nutrients in terrestrial ecosystems. Here, we present the first large‐scale synthesis of species trait effects on the early stages of fine root decomposition at both global and local scales. Based on decomposition rates for 279 plant species across 105 studies and 176 sites, we found that mycorrhizal association and woodiness are the best c...

Wetlands are the largest source of methane ( CH 4 ) globally, yet our understanding of how process‐level controls scale to ecosystem fluxes remains limited. It is particularly uncertain how variable soil properties influence ecosystem CH 4 emissions on annual time scales. We measured ecosystem carbon dioxide ( CO 2 ) and CH 4 fluxes by eddy covariance from two wetlands recently restored on peat and alluvium soils within the Sa...

Climate change is increasing the intensity of severe tropical storms and cyclones (also referred to as hurricanes or typhoons), with major implications for tropical forest structure and function. These changes in disturbance regime are likely to play an important role in regulating ecosystem carbon (C) and nutrient dynamics in tropical and subtropical forests. Canopy opening and debris deposition resulting from severe storms h...

Soil organic matter ( SOM ) supports the Earth's ability to sustain terrestrial ecosystems, provide food and fiber, and retains the largest pool of actively cycling carbon. Over 75% of the soil organic carbon ( SOC ) in the top meter of soil is directly affected by human land use. Large land areas have lost SOC as a result of land use practices, yet there are compensatory opportunities to enhance productivity and SOC storage i...

Wetlands can influence global climate via greenhouse gas ( GHG ) exchange of carbon dioxide ( CO 2 ), methane ( CH 4 ), and nitrous oxide (N 2 O). Few studies have quantified the full GHG budget of wetlands due to the high spatial and temporal variability of fluxes. We report annual open‐water diffusion and ebullition fluxes of CO 2 , CH 4 , and N 2 O from a restored emergent marsh ecosystem. We combined these data with concur...

Sea level rise will change inundation regimes in salt marshes, altering redox dynamics that control nitrification – a potential source of the potent greenhouse gas, nitrous oxide (N 2 O) – and denitrification, a major nitrogen (N) loss pathway in coastal ecosystems and both a source and sink of N 2 O. Measurements of net N 2 O fluxes alone yield little insight into the different effects of redox conditions on N 2 O production...

Livestock manure is applied to rangelands as an organic fertilizer to stimulate forage production, but the long‐term impacts of this practice on soil carbon (C) and greenhouse gas ( GHG ) dynamics are poorly known. We collected soil samples from manured and nonmanured fields on commercial dairies and found that manure amendments increased soil C stocks by 19.0 ± 7.3 Mg C ha −1 and N stocks by 1.94 ± 0.63 Mg N ha −1 compared to...

Lignin mineralization represents a critical flux in the terrestrial carbon (C) cycle, yet little is known about mechanisms and environmental factors controlling lignin breakdown in mineral soils. Hypoxia is thought to suppress lignin decomposition, yet potential effects of oxygen (O 2 ) variability in surface soils have not been explored. Here, we tested the impact of redox fluctuations on lignin breakdown in humid tropical fo...

Livestock manure management accounts for almost 10% of greenhouse gas emissions from agriculture globally, and contributes an equal proportion to the US methane emission inventory. Current emissions inventories use emissions factors determined from small‐scale laboratory experiments that have not been compared to field‐scale measurements. We compiled published data on field‐scale measurements of greenhouse gas emissions from w...

The enzymatic latch hypothesis proposes that oxygen (O 2 ) limitation promotes wetland carbon (C) storage by indirectly decreasing the activities of hydrolytic enzymes that decompose organic matter. Humid tropical forest soils are often characterized by low and fluctuating redox conditions and harbor a large pool of organic matter, yet they also have the fastest decomposition rates globally. We tested the enzymatic latch hypot...