Long-Term Nitrogen Addition Decreases Soil Carbon Mineralization in an N-Rich Primary Tropical Forest

Anthropogenic elevated nitrogen (N) deposition has an accelerated terrestrial N cycle, shaping soil carbon dynamics and storage through altering soil organic carbon mineralization processes. However, it remains unclear how long-term high N deposition affects soil carbon mineralization in tropical forests. To address this question, we established a long-term N deposition experiment in an N-rich lowland tropical forest of Southern China with N additions such as NH4NO3 of 0 (Control), 50 (Low-N), 100 (Medium-N) and 150 (High-N) kg N ha−1 yr−1, and laboratory incubation experiment, used to explore the response of soil carbon mineralization to the N additions therein. The results showed that 15 years of N additions significantly decreased soil carbon mineralization rates. During the incubation period from the 14th day to 56th day, the average decreases in soil CO2 emission rates were 18%, 33% and 47% in the low-N, medium-N and high-N treatments, respectively, compared with the Control. These negative effects were primarily aroused by the reduced soil microbial biomass and modified microbial functions (e.g., a decrease in bacteria relative abundance), which could be attributed to N-addition-induced soil acidification and potential phosphorus limitation in this forest. We further found that N additions greatly increased soil-dissolved organic carbon (DOC), and there were significantly negative relationships between microbial biomass and soil DOC, indicating that microbial consumption on soil-soluble carbon pool may decrease. These results suggests that long-term N deposition can increase soil carbon stability and benefit carbon sequestration through decreased carbon mineralization in N-rich tropical forests. This study can help us understand how microbes control soil carbon cycling and carbon sink in the tropics under both elevated N deposition and carbon dioxide in the future.

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Short-term compost application increases rhizosphere soil carbon mineralization and stimulates root growth in long-term continuously cropped cucumber

Scientia Horticulturae ◽

10.1016/j.scienta.2014.06.025 ◽

2014 ◽

Vol 175 ◽

pp. 269-277 ◽

Cited By ~ 9

Author(s):

Xueyan Zhang ◽

Yune Cao ◽

Yongqiang Tian ◽

Jianshe Li

Keyword(s):

Root Growth ◽

Soil Carbon ◽

Rhizosphere Soil ◽

Carbon Mineralization ◽

Short Term ◽

Compost Application ◽

Soil Carbon Mineralization

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Soil Carbon Mineralization and Microbial Biomass Carbon of In Situ and Exchange-Location Incubation in Forest along Urban-Rural Gradient

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.707.237 ◽

2014 ◽

Vol 707 ◽

pp. 237-242

Author(s):

Rui Lu ◽

Xiao Ying Peng ◽

Ming Quan Yu

Keyword(s):

Microbial Biomass ◽

Soil Carbon ◽

Rural Area ◽

Urban Soils ◽

Microbial Biomass Carbon ◽

Carbon Mineralization ◽

Biomass Carbon ◽

Urban Rural ◽

Soil Carbon Mineralization

Urbanization in high-speed nowadays is changing soil carbon dynamic. Soil carbon mineralization (Cm) and microbial biomass carbon (MBC) of in situ and exchange-location incubation was characterized along urban-rural gradient in Nanchang, China. As a result, soil Cm and MBC of in situ incubation were higher in urban than in suburban, which were significantly higher than those in rural area (P<0.05), at the same time, urban soils incubating in rural area mineralized about 1.8 times the amount of carbon than rural soils incubating in rural area; MBC in soils of exchange-location incubation exhibited a significant decrease tendency with area farther away from urban as well (P<0.05), while there was no significant difference observed in Cm of soils from the same origin incubating in different area between urban, suburban and rural (P>0.05). The result indicated that urban soils have potential for higher losses of carbon than rural soils.

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Plant acclimation to long-term high nitrogen deposition in an N-rich tropical forest

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1720777115 ◽

2018 ◽

Vol 115 (20) ◽

pp. 5187-5192 ◽

Cited By ~ 45

Author(s):

Xiankai Lu ◽

Peter M. Vitousek ◽

Qinggong Mao ◽

Frank S. Gilliam ◽

Yiqi Luo ◽

...

Keyword(s):

Tropical Forest ◽

Nutrient Balance ◽

N Deposition ◽

Water Leaching ◽

Ecosystem Responses ◽

Rooting Zone ◽

Foliar Nutrient ◽

Plant Acclimation ◽

N Additions

Anthropogenic nitrogen (N) deposition has accelerated terrestrial N cycling at regional and global scales, causing nutrient imbalance in many natural and seminatural ecosystems. How added N affects ecosystems where N is already abundant, and how plants acclimate to chronic N deposition in such circumstances, remains poorly understood. Here, we conducted an experiment employing a decade of N additions to examine ecosystem responses and plant acclimation to added N in an N-rich tropical forest. We found that N additions accelerated soil acidification and reduced biologically available cations (especially Ca and Mg) in soils, but plants maintained foliar nutrient supply at least in part by increasing transpiration while decreasing soil water leaching below the rooting zone. We suggest a hypothesis that cation-deficient plants can adjust to elevated N deposition by increasing transpiration and thereby maintaining nutrient balance. This result suggests that long-term elevated N deposition can alter hydrological cycling in N-rich forest ecosystems.

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Role of Biochar Amendment on Soil Carbon Mineralization and Microbial Biomass

Journal of Geoscience and Environment Protection ◽

10.4236/gep.2018.611013 ◽

2018 ◽

Vol 06 (11) ◽

pp. 173-180

Author(s):

Yimin Wang ◽

Ming Li

Keyword(s):

Microbial Biomass ◽

Soil Carbon ◽

Carbon Mineralization ◽

Soil Carbon Mineralization ◽

Biochar Amendment

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Carbon storage in seagrass soils: long-term nutrient history exceeds the effects of near-term nutrient enrichment

Biogeosciences ◽

10.5194/bg-13-313-2016 ◽

2016 ◽

Vol 13 (1) ◽

pp. 313-321 ◽

Cited By ~ 28

Author(s):

A. R. Armitage ◽

J. W. Fourqurean

Keyword(s):

Organic Carbon ◽

Soil Carbon ◽

Carbon Stock ◽

Seagrass Beds ◽

Nutrient Input ◽

High Carbon ◽

Phosphorus Addition ◽

Seagrass Biomass ◽

Near Term

Abstract. The carbon sequestration potential in coastal soils is linked to aboveground and belowground plant productivity and biomass, which in turn, is directly and indirectly influenced by nutrient input. We evaluated the influence of long-term and near-term nutrient input on aboveground and belowground carbon accumulation in seagrass beds, using a nutrient enrichment (nitrogen and phosphorus) experiment embedded within a naturally occurring, long-term gradient of phosphorus availability within Florida Bay (USA). We measured organic carbon stocks in soils and above- and belowground seagrass biomass after 17 months of experimental nutrient addition. At the nutrient-limited sites, phosphorus addition increased the carbon stock in aboveground seagrass biomass by more than 300 %; belowground seagrass carbon stock increased by 50–100 %. Soil carbon content slightly decreased ( ∼  10 %) in response to phosphorus addition. There was a strong but non-linear relationship between soil carbon and Thalassia testudinum leaf nitrogen : phosphorus (N : P) or belowground seagrass carbon stock. When seagrass leaf N : P exceeded an approximate threshold of 75 : 1, or when belowground seagrass carbon stock was less than 100 g m−2, there was less than 3 % organic carbon in the sediment. Despite the marked difference in soil carbon between phosphorus-limited and phosphorus-replete areas of Florida Bay, all areas of the bay had relatively high soil carbon stocks near or above the global median of 1.8 % organic carbon. The relatively high carbon content in the soils indicates that seagrass beds have extremely high carbon storage potential, even in nutrient-limited areas with low biomass or productivity.

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Long-term impacts of anthropogenic perturbations on dynamics and speciation of organic carbon in tropical forest and subtropical grassland ecosystems

Global Change Biology ◽

10.1111/j.1365-2486.2006.01304.x ◽

2007 ◽

Vol 13 (2) ◽

pp. 511-530 ◽

Cited By ~ 130

Author(s):

DAWIT SOLOMON ◽

JOHANNES LEHMANN ◽

JAMES KINYANGI ◽

WULF AMELUNG ◽

INGO LOBE ◽

...

Keyword(s):

Organic Carbon ◽

Tropical Forest ◽

Grassland Ecosystems ◽

Anthropogenic Perturbations

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Environmental Controls on Soil Microbial Communities in a Seasonally Dry Tropical Forest

Applied and Environmental Microbiology ◽

10.1128/aem.00342-18 ◽

2018 ◽

Vol 84 (17) ◽

Cited By ~ 8

Author(s):

Silvia Pajares ◽

Julio Campo ◽

Brendan J. M. Bohannan ◽

Jorge D. Etchevers

Keyword(s):

Tropical Forest ◽

Tropical Forests ◽

Soil Microbial Communities ◽

Soil Heterogeneity ◽

N Deposition ◽

Seasonally Dry Tropical Forest ◽

Content Type ◽

Soil Microbial ◽

Seasonally Dry ◽

Rainfall Seasonality

ABSTRACTSeveral studies have shown that rainfall seasonality, soil heterogeneity, and increased nitrogen (N) deposition may have important effects on tropical forest function. However, the effects of these environmental controls on soil microbial communities in seasonally dry tropical forests are poorly understood. In a seasonally dry tropical forest in the Yucatan Peninsula (Mexico), we investigated the influence of soil heterogeneity (which results in two different soil types, black and red soils), rainfall seasonality (in two successive seasons, wet and dry), and 3 years of repeated N enrichment on soil chemical and microbiological properties, including bacterial gene content and community structure. The soil properties varied with the soil type and the sampling season but did not respond to N enrichment. Greater organic matter content in the black soils was associated with higher microbial biomass, enzyme activities, and abundances of genes related to nitrification (amoA) and denitrification (nirKandnirS) than were observed in the red soils. Rainfall seasonality was also associated with changes in soil microbial biomass and activity levels and N gene abundances.Actinobacteria,Proteobacteria,Firmicutes, andAcidobacteriawere the most abundant phyla. Differences in bacterial community composition were associated with soil type and season and were primarily detected at higher taxonomic resolution, where specific taxa drive the separation of communities between soils. We observed that soil heterogeneity and rainfall seasonality were the main correlates of soil bacterial community structure and function in this tropical forest, likely acting through their effects on soil attributes, especially those related to soil organic matter and moisture content.IMPORTANCEUnderstanding the response of soil microbial communities to environmental factors is important for predicting the contribution of forest ecosystems to global environmental change. Seasonally dry tropical forests are characterized by receiving less than 1,800 mm of rain per year in alternating wet and dry seasons and by high heterogeneity in plant diversity and soil chemistry. For these reasons, N deposition may affect their soils differently than those in humid tropical forests. This study documents the influence of rainfall seasonality, soil heterogeneity, and N deposition on soil chemical and microbiological properties in a seasonally dry tropical forest. Our findings suggest that soil heterogeneity and rainfall seasonality are likely the main factors controlling soil bacterial community structure and function in this tropical forest. Nitrogen enrichment was likely too low to induce significant short-term effects on soil properties, because this tropical forest is not N limited.

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