Dejun Li

Dejun Li
Chinese Academy of Sciences | CAS · Institute of Subtropical Agriculture

PhD

About

144
Publications
43,711
Reads
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5,015
Citations
Additional affiliations
August 2013 - October 2018
Chinese Academy of Sciences
Position
  • Professor (Full)
April 2011 - June 2013
University of Oklahoma
Position
  • PostDoc Position
June 2009 - March 2011
University College Dublin
Position
  • PostDoc Position
Education
September 2004 - July 2007
University of Chinese Academy of Sciences
Field of study
  • Environmental Sciences
September 2001 - July 2004
University of Chinese Academy of Sciences
Field of study
  • Ecology
September 1997 - July 2001

Publications

Publications (144)
Article
Soil gross nitrogen (N) transformations are crucial for assessing forest N status. Although there is evidence suggesting that the N cycle is open in the karst forest, southwest China, process-based investigation of gross soil N transformations is limited. In the current study, gross soil N transformations were investigated using 15N isotope dilutio...
Article
It has been suggested that elevated nitrogen (N) deposition may increase soil N mineralization in N-limited ecosystems, but the underlying mechanisms have been not adequately explored. Soil N-acquisition enzymes play important roles on organic N mineralization. Thus, their responses to N deposition will be crucial for explaining the above phenomeno...
Article
Free-living biological N2 fixation (BNF) in soil, litter and moss is an important pathway for external nitrogen (N) inputs to unmanaged terrestrial ecosystems. However, how free-living BNF responses to temperature, moisture and their interaction have not been well understood, especially in the subtropical regions. Here we investigated the responses...
Article
Asymbiotic dinitrogen (N 2) fixation (ANF) plays an important role in determining forest nitrogen (N) availability. Yet, the controls on ANF variation within or between forests remain poorly understood. In the present study, ANF in bulk leaf litter (or litter ANF hereafter) and soil (or soil ANF hereafter) within the crown radius of the dominant tr...
Article
Soil microorganisms play a key role in soil biogeochemical cycles, but their growth and activities are often limited by resource availability. Understanding soil processes that are driven by microorganisms and resource limitation of microbes will help to elucidate controls on soil fertility and improve the ability to predict the responses of an eco...
Article
Full-text available
An ex-situ 15 N-18 O tracing experiment with soils collected from the valley and slope, respectively, of a subtropical secondary karst forest with three N addition levels, i.e., 0, 50, and 100 kg N ha −1 year −1 for each topographic position to investigate N 2 O production pathways. Autotrophic nitrification pathways (ammonia oxidation, nitrifier d...
Article
Full-text available
Anthropogenic nitrogen (N) deposition may substantially affect the contributions of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) to soil nitrous oxide (N 2 O) production. Nevertheless, it is still unclear whether topography modulates the responses of AOA-and AOB-derived N 2 O to elevated N deposition. We conducted an ex-situ...
Article
Microbial nitrogen (N) limitation is a common problem in terrestrial ecosystems. Pig manure, a type of solid waste, is increasingly applied to improve soil N availability in agriculture through inputs of organic matter and inorganic N. Pig manure application also introduces a lot of exogenous microorganisms, which have distinctly different N requir...
Article
Full-text available
Topography can influence nitrous oxide (N2O) emission via its influences on soil nutrient availability, moisture, and microbial communities. Nevertheless, it is still unclear whether topography modulates the responses of soil N2O emissions to elevated N deposition. Here the N addition experiment was conducted in the valley and on the slope of a sub...
Article
Full-text available
The impacts of enhanced nitrogen (N) deposition on the global forest carbon (C) sink and other ecosystem services may depend on whether N is deposited in reduced (mainly as ammonium) or oxidized forms (mainly as nitrate) and the subsequent fate of each. However, the fates of the two key reactive N forms and their contributions to forest C sinks are...
Article
Full-text available
The decomposition and transformation of organic matters during composting process are performed by various microorganisms. However, the bacterial communities and their functions usually vary with composting materials. Here the dominant bacterial genera and their functions were identified at the thermophilic phase during composting of mulberry branc...
Article
Full-text available
Soil respiration, the major pathway for ecosystem carbon (C) loss, has the potential to enter a positive feedback loop with the atmospheric CO2 due to climate warming. For reliable projections of climate-carbon feedbacks, accurate quantification of soil respiration and identification of mechanisms that control its variability are essential. Process...
Article
Full-text available
Background Nitrogen (N) saturation theory proposes that an ecosystem might switch from N limitation to carbon (C), phosphorus (P), or other nutrient limitations if it receives continuous N input. Yet, after N limitation is removed, which nutrient is the most limited and whether topography modulates such change is rarely tested at a microbial level....
Article
Full-text available
Sea level rise‐associated seawater intrusion exerts substantial impacts on the structure and function of coastal ecosystems. As nitrogen (N) availability is closely related to the structure and function of ecosystems, it is crucial to understand how seawater intrusion impacts biological N2 fixation, a major pathway of new N input to natural ecosyst...
Preprint
Full-text available
Background Nitrogen (N) saturation theory proposes that an ecosystem might switch from N limitation to carbon (C), phosphorus (P), or other nutrient limitations if it receives continuous N input. Yet, after N limitation is removed, which nutrient is the most limited and whether topography modulates such change is rarely tested at a microbial level....
Article
Full-text available
Biological N2 fixation plays crucial roles in determining the pattern and pace of ecological succession and carbon sequestration. Nevertheless, the rates and controls of symbiotic (SNF) and free‐living (FNF) N2 fixation have rarely been investigated simultaneously. Here we measured SNF and soil FNF rates for eight early succession ecosystems domina...
Article
Leaf nutrient resorption is a critical nutrient conservation strategy. Previous studies focus mainly on resorption patterns of macronutrients, but resorption patterns of trace elements remain poorly understood. A meta‐analysis was conducted to explore the general patterns of the leaf resorption of eight trace elements [i.e., copper (Cu), molybdenum...
Article
Investigation of soil internal nitrogen cycles is useful for unraveling the mechanisms responsible for soil nitrogen availability change. Here, gross nitrogen transformations were investigated in a subtropical karst area after 16 years of vegetation restoration. The experiment included four treatments, i.e., (i) corn‐soybean rotation field (CR, con...
Article
Leaf resorption is critical for considerations of how plants use and recycle nutrients, but fundamental unknowns remain regarding the controls over plant nutrient resorption. Empirical studies suggest at least three basic types of resorption control, including (i) stoichiometric control, (ii) nutrient limitation control, and (iii) nutrient concentr...
Article
Vegetation restoration has been proposed as an effective strategy for increasing soil organic carbon (SOC) sequestration. However, the responses of SOC to managed and natural vegetation restoration strategies at a large scale are poorly understood due to the varying SOC components and changing climatic conditions. Here, we measured bulk SOC, partic...
Article
Land use effects on the biogeochemical cycling of the essential trace element selenium (Se) and underlying mechanisms are not well understood yet. Here, total Se (Setotal) and its potential bioavailability, as represented by phosphate extractability (Sephosphate), were evaluated in top soils (0–15 cm) of cropland and woodland over two contrasting g...
Article
Full-text available
Globally water‐soluble organic nitrogen (WSON) accounts for about one third of water‐soluble total nitrogen in atmospheric deposition, yet the key factors influencing WSON deposition remain uncertain. In the present study, precipitation and aerosol samples were collected during 2016–2018 at a forest site in the Pearl River Delta, south China. Rainw...
Article
Full-text available
Excess nitrogen deposition has significant impacts on water eutrophication, soil acidification, eleveted greenhouse gas emissions, and biodiversity loss. These impacts mostly derive from conventional manipulative experiments in the field by adding nitrogen solution directly onto grassland or forest floors. For forest ecosystems, previous field expe...
Preprint
Full-text available
Soil microbial respiration is an important source of uncertainty in projecting future climate and carbon (C) cycle feedbacks. Despite intensive studies for two decades, the magnitude, direction, and duration of such feedbacks are uncertain, and their underlying microbial mechanisms are still poorly understood. Here we examined the responses of soil...
Article
Full-text available
Inorganic nitrogen (N) deposition in China is among the highest in the world, yet organic N deposition in the country has not been well constrained. In this study, wet and dry depositions of both organic and inorganic N were observed for 2 years at three contrasting sites (urban‐rural‐forest) in the Pearl River Delta (PRD) region, South China. Dete...
Article
Full-text available
The traditional view holds that biological nitrogen (N) fixation often peaks in early‐ or mid‐successional ecosystems and declines throughout succession based on the hypothesis that soil N richness and/or phosphorus (P) depletion become disadvantageous to N fixers. This view, however, fails to support the observation that N fixers can remain active...
Article
Full-text available
Evidence shows that nitrogen (N) addition may suppress or have no significant effect on asymbiotic N2 fixation (ANF) in soil, litter, or moss. However, the mechanisms underlying the differential responses of ANF to N addition are not well understood. The main objectives of the current study were to assess how ANF in soil, litter, and moss responds...
Article
Microbial residues are an important constituent of persistent soil organic carbon (SOC). Nevertheless, how microbial residue contribution to bulk SOC sequestration changes following land use conversion remains poorly understood. Here, we investigated the variation of soil microbial residue C and its contribution to SOC following conversion of maize...
Article
Knowledge about resource limitation to soil microbes is crucial for understanding ecosystem functions and processes, and for predicting ecosystem responses to global changes as well. Karst ecosystems are widespread in the world, and play a key role in regulating the global climate, however, the patterns of and mechanisms underlying microbial resour...
Article
Gross nitrogen (N) transformations are crucial in determining soil N status, but how gross N transformations change during post-agricultural succession remains poorly understood. Here, gross N transformations were measured using a 15 N isotope dilution technique in a subtropical karst region, southwest China. A stratified random sampling scheme was...
Article
Free-living N2 fixation is an important pathway of external nitrogen input to natural terrestrial ecosystems. However, few measurements of N2 fixation have been conducted in shrublands. Here, free-living N2 fixation in soil (or soil N2 fixation) and litter (or litter N2 fixation) in three shrublands was measured in a karst catchment, southwest Chin...
Article
Nitrogen (N) deposition may change carbon (C) or nutrient limitation of soil microbes, but whether such change can be reflected by ecoenzymatic stoichiometry has not been well studied. Here, we synthesized data from 36 published studies to evaluate the responses of ecoenzymatic stoichiometry to N addition. Results showed that N addition did not cha...
Article
Whether conservation agriculture systems can increase soil organic carbon (SOC) and total nitrogen (TN) pools remains unresolved. We measured SOC and TN pools in maize–soybean rotation fields and three types of conservation agriculture systems with mature forests being selected for comparison in southwest China's karst areas. The three types of con...
Article
Changes in the timing and magnitude of precipitation is a threat to agricultural productivity and farmland carbon stocks. However, the relationship between inter-annual variations in precipitation and net ecosystem CO 2 exchange (NEE) remains to be clarified, particularly when combined with water-salt transport in reclaimed coastal wetland. Here, b...
Article
Variation of soil microbial community abundance and structure has great implications for soil fertility and nutrient cycling. A better understanding of soil microbial community dynamics under different land use types is undoubtedly needed in order to develop sustainable land use schemes. The current study aimed to assess how soil microbial communit...
Article
Elevated nitrogen (N) deposition can alter the composition and availability of soil phosphorus (P) and thus affect long-term plant growth. However, it remains elusive whether this effect differs between legume and non-legume forest ecosystems, which have distinctly different abilities to use N and P. In this study, soil P fractions were measured in...
Article
Full-text available
Lowland tropical forests with chronic nitrogen (N) deposition and/or abundant N-fixing organisms are commonly rich in N relative to other nutrients. The tropical N richness introduces a paradoxical relationship in which many tropical forests sustain high rates of asymbiotic N fixation despite the soil N richness and the higher energy cost of N fixa...
Article
Gross nitrogen (N) transformations can provide important information for assessing indigenous soil N supply capacity and soil nitrate leaching potential. The current study aimed to assess the variation of gross N transformations in response to conversion of maize-soybean fields to sugarcane, mulberry, and forage grass fields in a subtropical karst...
Article
Soil nitrogen (N) availability is crucial in governing the dynamics of ecosystem structure and function. However, the variation pattern of soil N availability during post-agricultural succession has been poorly understood for karst regions. Here, soil N availability variables, including concentrations of soil total N (TN), dissolved inorganic N (DI...
Article
Full-text available
Strategies of plant N acquisition among coexisting species are critical for many aspects of ecosystems with differential uptake of various N forms as one of these strategies, but much debate still exists. In the present study, strategic N uptake of nitrate and ammonium by 30 dominant species were investigated over two post-agricultural succession s...
Article
Information on the bioaccumulation of selenium (Se) in soil invertebrates (e.g. earthworms) is rather scarce. In the present study, bioaccumulation of Se in two eco-physiologically different earthworms, namely anecic Pheretima guillemi and epigeic Eisenia fetida, was determined after 28 days exposure to a successive doses of Se-spiked soil, specifi...
Article
Ecological restoration is widespread in the karst region, southwest China, but the impacts of different restoration strategies on soil fertility indices have rarely been compared. Here soil nutrients and microbial communities were measured 16 years after agricultural abandonment in a karst area, southwest China. Three restoration strategies were in...
Chapter
Full-text available
This book is a contribution to the debate and knowledge for the rebalancing of farming and food using legumes. The main aim is to help people who are involved in developing cropping systems: the decision makers of today and today's students who are the decision makers of tomorrow. It is aimed at all relevant decision makers: farmers, professionals...
Article
Agricultural abandonment has been proposed as an effective way to enhance soil organic carbon (SOC) sequestration. Nevertheless, SOC sequestration in the long term is largely determined by whether the stable SOC fractions will increase. Here the dynamics of SOC fractions during post-agricultural succession were investigated in a karst region, south...
Article
Full-text available
Ecosystems usually recover from disturbance until a stable state, during which carbon (C) is accumulated to compensate for the C loss associated with disturbance events. However, it is not well understood how likely it is for an ecosystem to recover to an alternative state and how long it takes to recover toward a stable state. Here, we synthesized...
Article
Afforestation is regarded as an effective way to sequester soil organic carbon (C) and hence to attenuate global warming. Nevertheless, so far mechanisms underlying the direction and magnitude of soil C pool variation following afforestation are not well understood. Here soil organic C, total nitrogen (N) and total phosphorus (P) pools in surface m...
Article
Soil extracellular enzymes are crucial in biogeochemical cycle and ecosystem functioning. Yet uncertainty exists in terms of major determinants on soil extracellular enzyme activity (EEA), especially at calcareous areas. In this study, soil samples (0-15 cm) were collected from different topographic conditions (different slope positions and aspects...
Article
Soil extracellular enzymes are crucial in biogeochemical cycling and ecosystem functioning. Most previous studies addressed the determinants of soil extracellular enzyme activity (EEA) in small-scale regions with acid soils, yet uncertainty exists in large-scale regions with alkaline soils. In this study, the activities of 7 soil extracellular enzy...
Article
Soil carbon (C) sequestration through cropland conversion has been regarded as a major strategy to absorb atmospheric CO2 and thus mitigate global warming, but much uncertainty still exists in terms of restoration strategies. In this study, soil C and nitrogen (N) were measured 13 years after cropland conversion in a karst area, southwest China. Fo...
Article
Phosphorus (P) availability can affect nitrogen (N) dynamics in forest soil, and this effect might depend largely on the soil N status of forest ecosystems. So far, however, this view has not been well tested among forests with contrasting N status. Here, we used a 6-year experiment with additions of N and P to evaluate the effects of P availabilit...
Article
Agricultural abandonment is regarded as a major driver of soil organic carbon (C) dynamics, but the mechanisms underlying the direction and magnitude of soil C dynamics following agricultural abandonment are poorly understood. Here, dynamics of soil C and N contents during post-agricultural succession were investigated in areas underlain by dolomit...
Article
Full-text available
It is well documented that phosphorus (P) input stimulates biological nitrogen (N) fixation (BNF) in tropical forests with non-legume trees. However, in tropical legume forests with soil N enrichment and P deficiency, the effects of P availability and its combination with N on BNF remain poorly understood. In this study, we measured BNF rate in dif...
Article
This study was aimed to investigate the direction and magnitude of soil organic carbon (SOC) dynamics and the underlying mechanisms following agricultural abandonment in a subtropical karst area, southwest China. Two post-agriculture succession sequences including grassland (~10 years), shrubland (~29 years), secondary forest (~59 years) and primar...
Article
Increased atmospheric nitrogen (N) deposition has been found to alter processes and functions of terrestrial ecosystems including the biogeochemical cycling of N and other elements, e.g., phosphorus (P), calcium (Ca) and potassium (K). Nevertheless, how N deposition changes sulfur (S) cycling is largely unknown. Based on a meta-analysis and a lab N...
Article
Importance: Global change involves simultaneous alterations, including those caused by climate warming and land management practices (e.g., clipping). Data on the interactive effects of warming and clipping on ecosystems remain elusive, particularly in microbial ecology. This study found that clipping alters microbial responses to warming and demo...
Article
Full-text available
Soil nitrogen (N) dynamics are crucial for ecosystem development and carbon sequestration. However, N dynamics during post-agriculture succession have not been well understood. Here soil N dynamics during post-agriculture succession were investigated in a subtropical karst area, southwest China. The succession sequence includes grassland (~10 years...
Article
Full-text available
Rates of biological nitrogen fixation (BNF) were measured in ecosystem. In this study, we measured rates of BNF in ecosystem compartments (bulk soil, forest floor, rhizosphere soil, and nodule) in two mature tropical plantations in southern China with legume trees (Acacia auriculiformis, AA) and with non-legume trees (Eucalyptus urophylla, EU) afte...
Article
Soil microbial communities play critical roles in ecosystem functioning and are likely altered by climate warming. However, so far, little is known about effects of warming on microbial functional gene expressions. Here, we applied functional gene array (GeoChip 3.0) to analyze cDNA reversely transcribed from total RNA to assess expressed functiona...