Priming effects induced by C and N additions in relation to microbial biomass turnover in Japanese forest soils

The relationship between a microbial biomass respiration response to added C and N (NIR) and N mineralized in buried-bags in the field was examined. Significant negative correlations were found between organic horizon NIR values and the amount of mineralized N measured at various times, however no significant correlations were found in the mineral horizon. These results suggest that NIR has potential for use as a physiological indicator of forest floor N availability. Key words: Microbial biomass, respiration, SIR, N mineralization

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Immobilized-S, microbial biomass-S and soil arylsulfatase activity in the rhizosphere soil of rape and barley as affected by labile substrate C and N additions

Soil Biology and Biochemistry ◽

10.1016/j.soilbio.2003.08.012 ◽

2003 ◽

Vol 35 (12) ◽

pp. 1651-1661 ◽

Cited By ~ 22

Author(s):

Phuy-Chhoy Vong ◽

Odile Dedourge ◽

Françoise Lasserre-Joulin ◽

Armand Guckert

Keyword(s):

Microbial Biomass ◽

Rhizosphere Soil ◽

Arylsulfatase Activity ◽

C And N ◽

N Additions

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Microbial biomass C and N dynamics, and 15N incorporation into microbial biomass under faba bean, canola, barley, and summer fal- low in a Gray Luvisol

Applied Environmental Biotechnology ◽

10.26789/aeb.2017.01.007 ◽

2017 ◽

Vol 2 (2) ◽

pp. 47-58

Author(s):

Ji-Dong Gu ◽

◽

William B McGill ◽

◽

Keyword(s):

Microbial Biomass ◽

Faba Bean ◽

Microbial Biomass C ◽

N Dynamics ◽

C And N ◽

Gray Luvisol ◽

C And N Dynamics

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

Forests ◽

10.3390/f12060734 ◽

2021 ◽

Vol 12 (6) ◽

pp. 734

Author(s):

Xiankai Lu ◽

Qinggong Mao ◽

Zhuohang Wang ◽

Taiki Mori ◽

Jiangming Mo ◽

...

Keyword(s):

Microbial Biomass ◽

Organic Carbon ◽

Tropical Forest ◽

Soil Carbon ◽

Tropical Forests ◽

Carbon Mineralization ◽

N Deposition ◽

Soil Carbon Mineralization ◽

N Additions

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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Warming affects seasonal dynamics of microorganisms and reduces the N storage capacity of soil microbes in winter

10.5194/egusphere-egu21-13232 ◽

2021 ◽

Author(s):

Philipp Gündler ◽

Alberto Canarini ◽

Sara Marañón Jiménez ◽

Gunnhildur Gunnarsdóttir ◽

Páll Sigurðsson ◽

...

Keyword(s):

Microbial Biomass ◽

Growth Rates ◽

Seasonal Dynamics ◽

Soil Microbes ◽

Storage Capacity ◽

Ambient Conditions ◽

Soil Warming ◽

Carbon Use Efficiency ◽

Use Efficiency ◽

C And N

Seasonality of soil microorganisms plays a critical role in terrestrial carbon (C) and nitrogen (N) cycling. The asynchrony of immobilization by microbes and uptake by plants may be important for N retention during winter, when plants are inactive. Meanwhile, the known warming effects on soil microbes (decreasing biomass and increasing growth rates) may affect microbial seasonal dynamics and nutrient retention during winter.We sampled soils from a geothermal warming site in Iceland (www.forhot.is) which includes three in situ warming levels (ambient, +3 &#176;C, +6 &#176;C). We harvested soil samples at 9 time points over one year and measured the seasonal variation in microbial biomass carbon (Cmic) and nitrogen (Nmic) and microbial physiology (growth and carbon use efficiency) by an 18O-labelling technique.We observed that Cmic and Nmic peaked in winter, followed by a decline in spring and summer. In contrast growth and respiration rates were higher in summer than winter. The observed biomass peak at lower growth rates, suggests that microbial death rates must have declined even more than growth rates. Soil warming increased biomass-specific microbial activity (i.e., growth, respiration, and turnover rates per unit of microbial biomass), prolonging the period of higher microbial activity found in summer into autumn and winter. Microbial carbon use efficiency was unaltered by soil warming. Throughout the seasons, warming reduced Cmic and Nmic, albeit with a stronger effect in winter than summer and restrained winter biomass accumulation by up to 78% compared to ambient conditions. We estimated a reduced microbial winter N storage capacity by 45.5 and 94.6 kg ha-1 at +3 &#176;C and +6 &#176;C warming respectively compared to ambient conditions. This reduction represents 1.57% and 3.26% of total soil N stocks, that could potentially be lost per year from these soils.Our results clearly demonstrate that soil warming strongly decreases microbial C and N immobilization when plants are inactive, potentially leading to higher losses of C and N from warmed soils over winter. These results have important implications as increased N losses may restrict increased plant growth in a future climate.

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Perennial herbaceous legumes as live soil mulches and their effects on C, N and P of the microbial biomass

Scientia Agricola ◽

10.1590/s0103-90162003000100021 ◽

2003 ◽

Vol 60 (1) ◽

pp. 139-147 ◽

Cited By ~ 33

Author(s):

Gustavo Pereira Duda ◽

José Guilherme Marinho Guerra ◽

Marcela Teixeira Monteiro ◽

Helvécio De-Polli ◽

Marcelo Grandi Teixeira

Keyword(s):

Microbial Biomass ◽

Soil Depth ◽

Vegetation Management ◽

Pueraria Phaseoloides ◽

Organic C ◽

Arachis Pintoi ◽

Factorial Combination ◽

C And N ◽

Microbial C ◽

Macroptilium Atropurpureum

The use of living mulch with legumes is increasing but the impact of this management technique on the soil microbial pool is not well known. In this work, the effect of different live mulches was evaluated in relation to the C, N and P pools of the microbial biomass, in a Typic Alfisol of Seropédica, RJ, Brazil. The field experiment was divided in two parts: the first, consisted of treatments set in a 2 x 2 x 4 factorial combination of the following factors: live mulch species (Arachis pintoi and Macroptilium atropurpureum), vegetation management after cutting (leaving residue as a mulch or residue remotion from the plots) and four soil depths. The second part had treatments set in a 4 x 2 x 2 factorial combination of the following factors: absence of live mulch, A. pintoi, Pueraria phaseoloides, and M. atropurpureum, P levels (0 and 88 kg ha-1) and vegetation management after cutting. Variation of microbial C was not observed in relation to soil depth. However, the amount of microbial P and N, water soluble C, available C, and mineralizable C decreased with soil depth. Among the tested legumes, Arachis pintoi promoted an increase of microbial C and available C content of the soil, when compared to the other legume species (Pueraria phaseoloides and Macroptilium atropurpureum). Keeping the shoot as a mulch promoted an increase on soil content of microbial C and N, total organic C and N, and organic C fractions, indicating the importance of this practice to improve soil fertility.

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Microbial biomass and activity in the humus layer following burning: short-term effects of two different fires

Canadian Journal of Forest Research ◽

10.1139/x93-163 ◽

1993 ◽

Vol 23 (7) ◽

pp. 1275-1285 ◽

Cited By ~ 72

Author(s):

Janna Pietikäinen ◽

Hannu Fritze

Keyword(s):

Microbial Community ◽

Microbial Biomass ◽

Soil Respiration ◽

Mass Loss ◽

Forest Fire ◽

Prescribed Burning ◽

Microbial Biomass C ◽

Soil Microbial ◽

Fungal Hyphae ◽

C And N

During a 3-year study, soil microbial biomass C and N, length of the fungal hyphae, soil respiration, and the percent mass loss of needle litter were recorded in coniferous forest soil humus layers following a prescribed burning (PB) treatment or a forest fire simulation (FF) treatment (five plots per treatment). Unburned humus from adjacent plots served as controls (PC and FC, respectively). Prescribed burning was more intensive than the forest fire, and this was reflected in all the measurements taken. The amounts of microbial biomass C and N, length of fungal hyphae, and soil respiration in the PB area did not recover to their controls levels, whereas unchanged microbial biomass N and recovery of the length of the fungal hyphae to control levels were observed in the FF area. The mean microbial C/N ratio was approximately 7 in all the areas, which reflected the C/N ratio of the soil microbial community. Deviation from this mean value, as observed during the first three samplings from the PB area (3, 18, and 35 days after fire treatment), suggested a change in the composition of the microbial community. Of the two treated areas, the decrease in soil respiration (laboratory measurements) was much more pronounced in the PB area. However, when the humus samples from both areas were adjusted to 60% water holding capacity, no differences in respiration capacity were observed. The drier humus, due to higher soil temperatures, of the PB area is a likely explanation for the low soil respiration. Lower soil respiration was not reflected in lower litter decomposition rates of the PB area, since there was a significantly higher needle litter mass loss during the first year in the PB area followed by a decline to the control level during the second year. Consistently higher mass losses were recorded in the FC area than in the FF area.

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