scholarly journals Soil N Fluxes in Three Contrasting Dry Tropical Forests

2001 ◽  
Vol 1 ◽  
pp. 534-538
Author(s):  
Naoko Tokuchi ◽  
Asami Nakanishi ◽  
Chongrak Wachirinrat ◽  
Hiroshi Takeda
Keyword(s):  
Tropical Forests ◽  
N Cycling ◽  
Evergreen Forest ◽  
Wet Season ◽  
Soil C ◽  
Fine Soil ◽  
Resin Core ◽  
N Fluxes ◽  
Dry Tropical Forests ◽  
C And N

A comparative study of N fluxes in soil among a dry dipterocarp forest (DDF), a dry evergreen forest (DEF), and a hill evergreen forest (HEF) in Thailand was done. N fluxes in soil were estimated using an ion exchange resin core method and a buried bag method. Soil C and N pools were 38 C Mg/ha/30 cm and 2.5 N Mg/ha/30 cm in DDF, 82 C Mg/ha/30 cm and 6.2 N Mg/ha/30 cm in DEF, and 167 C Mg/ha/30 cm and 9.3 N Mg/ha/30 cm in HEF. Low C concentration in the DDF and DEF sites was compensated by high fine soil content. In the highly weathered tropical soil, fine soil content seemed to be important for C accumulation. Temporal and vertical fluctuations of N fluxes were different among the sites. The highest N flux was exhibited at the onset of the wet season in DDF, whereas inorganic N production and estimated uptake of N were relatively stable during the wet season in DEF and HEF. It is suggested that N cycling in soil becomes stable in dry tropical forests to intermediate in temperate forests. N deposition may result in large changes of N cycling in the DDF and DEF due to low accumulations of C and N.

Soil C and N dynamics in primary and secondary seasonally dry tropical forests in Mexico

2005 ◽  
Vol 29 (3) ◽  
pp. 282-289 ◽  
Author(s):  
Vinisa Saynes ◽  
Claudia Hidalgo ◽  
Jorge D. Etchevers ◽  
Julio E. Campo
Keyword(s):  
Tropical Forests ◽  
N Dynamics ◽  
Soil C ◽  
Seasonally Dry ◽  
Seasonally Dry Tropical Forests ◽  
Dry Tropical Forests ◽  
Soil C And N ◽  
C And N ◽  
C And N Dynamics

The magnitude of temperature increase matters: how will soil organic mineralization respond to future climate warming?

2020 ◽  
Author(s):  
Jie Zhou ◽  
Yuan Wen ◽  
Lingling Shi ◽  
Michaela Dippold ◽  
Yakov Kuzyakov ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Climate Warming ◽  
Temperature Increase ◽  
Microbial Growth ◽  
N Cycling ◽  
Soil C ◽  
Soil Microbial ◽  
Soil C And N ◽  
C And N ◽  
C And N Cycling

<p>The Paris climate agreement is pursuing efforts to limit the increase in global temperature to below 2 °C above pre-industrial level. The overall consequence of relatively slight warming (~2 °C), on soil C and N stocks will be dependent on microorganisms decomposing organic matter through release of extracellular enzymes. Therefore, the capacity of soil microbial community to buffer climate warming in long-term and the self-regulatory mechanisms mediating soil C and N cycling through enzyme activity and microbial growth require a detailed comparative study. Here, microbial growth and the dynamics of enzyme activity (involved in C and N cycling) in response to 8 years warming (ambient, +1.6 °C, +3.2 °C) were investigated to identify shifts in soil and microbial functioning. A slight temperature increase (+1.6 °C) only altered microbial properties, but had no effect on either hydrolytic enzyme activity or basic soil properties. Stronger warming (+3.2 °C) increased the specific growth rate (μ<sub>m</sub>) of the microbial community, indicating an alteration in their ecological strategy, i.e. a shift towards fast-growing microorganisms and accelerated microbial turnover. Warming strongly changed microbial physiological state, as indicated by a 1.4-fold increase in the fraction of growing microorganisms (GMB) and 2 times decrease in lag-time with warming. This reduced total microbial biomass but increased specific enzyme activity to be ready to decompose increased rhizodeposition, as supported by the higher potential activitiy (V<sub>max</sub>) and lower affinity to substrates (higher K<sub>m</sub>) of enzymes hydrolyzing cellobiose and proteins cleavage in warmed soil. In other words, stronger warming magnitude (+3.2 °C) changed microbial communities, and was sufficient to benefit fast-growing microbial populations with enzyme functions that specific to degrade labile SOM. Combining with 48 literature observations, we confirmed that the slight magnitude of temperature increase (< 2 °C) only altered microbial properties, but further temperature increases (2-4 °C) was sufficient to change almost all soil, microbial, and enzyme properties and related processes. As a consequence, the revealed microbial regulatory mechanism of stability of soil C storage is strongly depended on the magnitude of future climate warming.</p>

scholarly journals Modeling the effects of tree species and incubation temperature on soil's extracellular enzyme activity in 78-year-old tree plantations

2017 ◽  
Vol 14 (23) ◽  
pp. 5393-5402 ◽  
Author(s):  
Xiaoqi Zhou ◽  
Shen S. J. Wang ◽  
Chengrong Chen
Keyword(s):  
Tree Species ◽  
Incubation Temperature ◽  
N Cycling ◽  
Residual Soil ◽  
Coniferous Tree ◽  
Soil C ◽  
Hoop Pine ◽  
Soil C And N ◽  
C And N ◽  
Coniferous Tree Species

Abstract. Forest plantations have been widely used as an effective measure for increasing soil carbon (C), and nitrogen (N) stocks and soil enzyme activities play a key role in soil C and N losses during decomposition of soil organic matter. However, few studies have been carried out to elucidate the mechanisms behind the differences in soil C and N cycling by different tree species in response to climate warming. Here, we measured the responses of soil's extracellular enzyme activity (EEA) to a gradient of temperatures using incubation methods in 78-year-old forest plantations with different tree species. Based on a soil enzyme kinetics model, we established a new statistical model to investigate the effects of temperature and tree species on soil EEA. In addition, we established a tree species–enzyme–C∕N model to investigate how temperature and tree species influence soil C∕N contents over time without considering plant C inputs. These extracellular enzymes included C acquisition enzymes (β-glucosidase, BG), N acquisition enzymes (N-acetylglucosaminidase, NAG; leucine aminopeptidase, LAP) and phosphorus acquisition enzymes (acid phosphatases). The results showed that incubation temperature and tree species significantly influenced all soil EEA and Eucalyptus had 1.01–2.86 times higher soil EEA than coniferous tree species. Modeling showed that Eucalyptus had larger soil C losses but had 0.99–2.38 times longer soil C residence time than the coniferous tree species over time. The differences in the residual soil C and N contents between Eucalyptus and coniferous tree species, as well as between slash pine (Pinus elliottii Engelm. var. elliottii) and hoop pine (Araucaria cunninghamii Ait.), increase with time. On the other hand, the modeling results help explain why exotic slash pine can grow faster, as it has 1.22–1.38 times longer residual soil N residence time for LAP, which mediate soil N cycling in the long term, than native coniferous tree species like hoop pine and kauri pine (Agathis robusta C. Moore). Our results will be helpful for understanding the mechanisms of soil C and N cycling by different tree species, which will have implications for forest management.

scholarly journals Aeolian nutrient fluxes following wildfire in sagebrush steppe: implications for soil carbon storage

2011 ◽  
Vol 8 (4) ◽  
pp. 8323-8349 ◽  
Author(s):  
N. J. Hasselquist ◽  
M. J. Germino ◽  
J. B. Sankey ◽  
L. J. Ingram ◽  
N. F. Glenn
Keyword(s):  
Biogeochemical Cycling ◽  
Total Carbon ◽  
Sagebrush Steppe ◽  
Nutrient Fluxes ◽  
Aeolian Transport ◽  
Organic C ◽  
Soil C ◽  
N Fluxes ◽  
C And N ◽  
Semi Arid

Abstract. Pulses of aeolian transport following fire can profoundly affect the biogeochemical cycling of nutrients in semi-arid and arid ecosystems. Our objective was to determine horizontal nutrient fluxes during an episodic pulse of aeolian transport that occurred following a wildfire in a semi-arid sagebrush steppe ecosystem in southern Idaho, USA. We also examined how temporal trends in nutrient fluxes were affected by changes in particle sizes of eroded mass as well as nutrient concentrations associated with different particle size classes. In the burned area, total carbon (C) and nitrogen (N) fluxes were as high as 235 g C m−1 d−1 and 19 g N m−1 d−1 during the first few months following fire, whereas C and N fluxes were negligible in an adjacent unburned area throughout the study. Temporal variation in C and N fluxes following fire was largely attributable to the redistribution of saltation-sized particles. Total N and organic C concentrations in the soil surface were significantly lower in the burned relative to the unburned area one year after fire. Our results show how an episodic pulse of aeolian transport following fire can affect the spatial distribution of soil C and N, which, in turn, can have important implications for soil C storage. These findings demonstrate how an ecological disturbance can exacerbate a geomorphic process and highlight the need for further research to better understand the role aeolian transport plays in the biogeochemical cycling of C and N in recently burned landscapes.

Occurrence and distribution of fungal endophytes in tropical forests across a rainfall gradient

2002 ◽  
Vol 80 (8) ◽  
pp. 818-826 ◽  
Author(s):  
T S Suryanarayanan ◽  
T S Murali ◽  
G Venkatesan
Keyword(s):  
Tropical Forests ◽  
Forest Type ◽  
Fungal Endophytes ◽  
Evergreen Forest ◽  
Forest Types ◽  
Wet Season ◽  
Rainfall Gradient ◽  
Entire Plant ◽  
Different Types ◽  
The Western Ghats

Fungal endophytes occur in leaves of angiosperm and gymnosperm trees. The occurrence and distribution of fungal endophytes in the leaves of trees growing in four different types of tropical forests in the Western Ghats were studied. One thousand five hundred leaf segments from five different hosts were screened for each forest type. Endophyte communities of trees of the semi-evergreen forest showed the highest species diversity. More endophyte isolates were recovered during the wet season. Although several genera of endophytes were common for different hosts growing in different forests, the dominant endophyte was different for different forest types. Our results suggest that although tropical trees individually may be endophyte rich, the overall endophyte diversity of the entire plant community is not exceptional.Key words: tropical forests, fungal endophytes, fungal diversity, foliar endophytes.

scholarly journals Aeolian nutrient fluxes following wildfire in sagebrush steppe: implications for soil carbon storage

2011 ◽  
Vol 8 (12) ◽  
pp. 3649-3659 ◽  
Author(s):  
N. J. Hasselquist ◽  
M. J. Germino ◽  
J. B. Sankey ◽  
L. J. Ingram ◽  
N. F. Glenn
Keyword(s):  
Biogeochemical Cycling ◽  
Total Carbon ◽  
Sagebrush Steppe ◽  
Nutrient Fluxes ◽  
Aeolian Transport ◽  
Organic C ◽  
Soil C ◽  
N Fluxes ◽  
C And N ◽  
Semi Arid

Abstract. Pulses of aeolian transport following fire can profoundly affect the biogeochemical cycling of nutrients in semi-arid and arid ecosystems. Our objective was to determine horizontal nutrient fluxes occurring in the saltation zone during an episodic pulse of aeolian transport that occurred following a wildfire in a semi-arid sagebrush steppe ecosystem in southern Idaho, USA. We also examined how temporal trends in nutrient fluxes were affected by changes in particle sizes of eroded mass as well as nutrient concentrations associated with different particle size classes. In the burned area, total carbon (C) and nitrogen (N) fluxes were as high as 235 g C m−1 d−1 and 19 g N m−1 d−1 during the first few months following fire, whereas C and N fluxes were negligible in an adjacent unburned area throughout the study. Temporal variation in C and N fluxes following fire was largely attributable to the redistribution of saltation-sized particles. Total N and organic C concentrations in the soil surface were significantly lower in the burned relative to the unburned area one year after fire. Our results show how an episodic pulse of aeolian transport following fire can affect the spatial distribution of soil C and N, which, in turn, can have important implications for soil C storage. These findings demonstrate how an ecological disturbance can exacerbate a geomorphic process and highlight the need for further research to better understand the role aeolian transport plays in the biogeochemical cycling of C and N in recently burned landscapes.

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