Simulation of protozoa-induced mineralization of bacterial carbon and nitrogen

1992 ◽  
Vol 72 (3) ◽  
pp. 201-216 ◽  
Author(s):  
P. M. Rutherford ◽  
N. G. Juma
Keyword(s):  
N Mineralization ◽  
Ecological Research ◽  
Clay Loam ◽  
Glucose Addition ◽  
Soil C ◽  
Carbon And Nitrogen ◽  
Soil C And N ◽  
C And N ◽  
Typic Cryoboroll ◽  
Bacterial C

Modelling in soil ecological research is a means of linking the dynamics of microbial and faunal populations to soil processes. The objectives of this study were (i) to simulate bacterial-protozoan interactions and flows of C and N in clay loam Orthic Black Chernozemic soil under laboratory condtions; and (ii) to quantify the flux of C and N (inputs and outputs) through various pools using the simulation model. The unique features of this model are: (i) it combines the food chain with specific soil C and N pools, and (ii) it simultaneously traces the flows of C, 14C, N and 15N. It was possible to produce a model that fitted the data observed for the soil. The simulated CO2-C evolved during the first 12 d was due mainly to glucose addition (171 μg C g−1 soil) and cycling of C in the soil (160 μg C g−1 soil). During this interval, bacterial C uptake was 5.5-fold greater than the initial bacterial C pool size. In the first 12 d protozoa directly increased total CO2-C evolution by 11% and increased NH4-N mineralization 3-fold, compared to soil containing only bacteria. Mineralization of C and N was rapid when bacterial numbers were increased as a result of glucose addition. Key words: Acanthamoeba sp., modelling, N mineralization-immobilization, organic matter, Pseudomonas sp., Typic Cryoboroll

Influence of soil texture on protozoa-induced mineralization of bacterial carbon and nitrogen

1992 ◽  
Vol 72 (3) ◽  
pp. 183-200 ◽  
Author(s):  
P. M. Rutherford ◽  
N. G. Juma
Keyword(s):  
N Mineralization ◽  
Pore Space ◽  
Mineralization Rate ◽  
Microcosm Experiment ◽  
Carbon And Nitrogen ◽  
Protozoan Grazing ◽  
C And N ◽  
Typic Cryoboroll ◽  
Bacterial C

Texture affects pore space, bacterial and protozoan populations and their activity in soil. The objective of this study was to test the hypothesis that protozoa grazing on bacteria increase the mineralization of bacterial C and N more in coarse-textured soils than in fine-textured soils. The microcosm experiment consisted of samples from three sterilized Orthic Black Chernozemic soils (SiC, CL and SL) inoculated with Pseudomonos bacteria, two treatments (with and without protozoa), and five sampling dates. The Pseudomonas population was labelled in situ by adding glucose- 14C and KNO3-15N (day 0). A species of Acanthamoeba was added to the microcosms on Day 2. On Day 4 bacterial numbers in all three soils were approximately 3 × 109 g−1 soil. The greatest reduction of bacteria due to protozoan grazing occurred between day 4 and day 7. All soils showed increased CO2-14C evolution and NH4-15N mineralization due to protozoan grazing but the mineralization rate of labelled N in the SL soil was much greater than in the fine-textured soils. The effect of texture on protozoan grazing was not as marked between day 12 and day 37 as earlier in the incubation. Protozoan-induced effects were transient in the soils studied and were most apparent in the coarse-textured soil. Key words: 14C, 15N, N mineralization-immobilization, bacteria, organic matter, Typic Cryoboroll, porosity, protozoa

Soil carbon and nitrogen pools and processes in an old-growth conifer forest 13 years after trenching

1998 ◽  
Vol 28 (8) ◽  
pp. 1261-1265 ◽  
Author(s):  
Stephen C Hart ◽  
Phil Sollins
Keyword(s):  
Water Content ◽  
N Mineralization ◽  
Microbial Biomass C ◽  
Net N Mineralization ◽  
Conifer Forest ◽  
Old Growth ◽  
Soil C ◽  
Carbon And Nitrogen ◽  
Soil C And N ◽  
C And N

We measured surface soil (0-15cm) C and N pools and processes inside and outside an area that had been trenched 13 years earlier in an old-growth conifer forest (>450 years) to assess the long-term impacts of reduced root inputs on C and N turnover. Trenching, combined with frequent clipping of understory plants, was originally conducted to prevent nutrient uptake by plants, as part of a study of the role of vegetation in ecosystem retention of N. Thirteen years following trenching, the median values of bulk density, pH, total C and N concentrations, annual rates of in situ net N mineralization and nitrification, microbial biomass C and N, microbial respiration, and anaerobically mineralizable N in the trenched plot were all within the 25-75% interquartile range of values found in the replicated, untrenched plots. The trenched plot had higher rates of net N mineralization (41% higher in October, 484% higher in June) and net nitrification (25% higher in October, and lower net NO3- immobilization in June) during laboratory incubation and a 22% higher water content in October. In June, soil water content in the trenched plot was about 8% lower than in the untrenched plots. Our results suggest that soil C and N dynamics in these old-growth forests are relatively resistant to perturbations resulting from major reductions in root input to the soil.

scholarly journals Forest type affects the coupled relationships of soil C and N mineralization in the temperate forests of northern China

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Quan Quan ◽  
Changhui Wang ◽  
Nianpeng He ◽  
Zhen Zhang ◽  
Xuefa Wen ◽  
...  
Keyword(s):  
N Mineralization ◽  
Temperate Forests ◽  
Forest Type ◽  
Northern China ◽  
Soil C ◽  
C And N Mineralization ◽  
Soil C And N ◽  
C And N

Tree species and time since afforestation drive soil C and N mineralization on former cropland

Geoderma ◽  
2017 ◽  
Vol 305 ◽  
pp. 153-161 ◽  
Author(s):  
M.M. Rahman ◽  
T.G. Bárcena ◽  
L. Vesterdal
Keyword(s):  
Tree Species ◽  
N Mineralization ◽  
Soil C ◽  
C And N Mineralization ◽  
Soil C And N ◽  
C And N

scholarly journals Soil Type and a Labile C Addition Regime Control the Temperature Sensitivity of Soil C and N Mineralization More than N Addition in Wetland Soils in China

Atmosphere ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1043
Author(s):  
Chunmei Wang ◽  
Yunyun Zhang ◽  
Yun Li
Keyword(s):  
Temperature Sensitivity ◽  
N Mineralization ◽  
Wetland Soils ◽  
Co2 Efflux ◽  
N Addition ◽  
Soil C ◽  
C And N Mineralization ◽  
Labile C ◽  
Soil C And N ◽  
C And N

Wetlands store a large amount of carbon (C) and many are vulnerable to potential global warming. It is critical to quantify the temperature sensitivity of soil nitrogen (N) and C mineralization in response to external labile C or N addition in different types of wetland. Through incubation experiments, the effects of temperature and the addition of N or C on soil C and N mineralization were tested using soils from the Sanjiang Plain wetland (SW), Zoigê alpine wetland (ZW), Yellow River estuary wetland (YW), and Baiyangdian Lake (BL). Our findings showed that temperature, available C and wetland type were dominant factors in the regulation of soil C loss, with soil C in SW and ZW being less stable and poorly resistant to increases in temperature. The response of net N mineralization to N addition showed regional differences. A lack of long-term effects of the deposition of N on soil mineralization suggested that there may be a particular N addition threshold level for changed C and N mineralization. It is predicted that an increase in labile C supply due to elevated carbon dioxide (CO2) and its interactions with wetland types will increase CO2 efflux more than N deposition in wetland soils.

scholarly journals Moisture effect on carbon and nitrogen mineralization in topsoil of Changbai Mountain, Northeast China

2011 ◽  
Vol 57 (No. 8) ◽  
pp. 340-348 ◽  
Author(s):  
G. Qi ◽  
Q. Wang ◽  
W. Zhou ◽  
H. Ding ◽  
X. Wang ◽  
...  
Keyword(s):  
N Mineralization ◽  
Northeast China ◽  
Vegetation Type ◽  
Changbai Mountain ◽  
Annual Precipitation ◽  
Soil C ◽  
Natural Reserve ◽  
C And N Mineralization ◽  
Soil C And N ◽  
C And N

Changbai Mountain Natural Reserve (1,985 km<sup>2</sup> and 2,734 m a.s.l.) of Northeast China is a typical ecosystem representing the temperate biosphere. The vegetation is vertically divided into 4 dominant zones: broadleaved Korean pine forest (annual temperature 2.32&deg;C, annual precipitation 703.62 mm), dark coniferous forest (annual temperature &ndash;1.78&deg;C, annual precipitation 933.67 mm), Erman's birch forest (annual temperature &ndash;2.80&deg;C, annual precipitation 1,002.09 mm) and Alpine tundra (annual temperature &ndash;3.82&deg;C, annual precipitation 1,075.53 mm). Studies of soil carbon (C) and nitrogen (N) mineralization have attracted wide attention in the context of global climate change. Based on the data of a 42-day laboratory incubation experiment, this paper investigated the relationship between soil moisture and mineralization of C and N in soils with different vegetation types on the northern slope of the Natural Reserve Zone of Changbai Mountain. The elevation influence on soil C and N mineralization was also discussed. The results indicated that for the given vegetation type of Changbai Mountain the C and N mineralization rate, potential mineralizable C (C0) and potential rate of initial C mineralization (C<sub>0</sub>k) all increased as the soil moisture rose. The elevation or vegetation type partially affected the soil C and N mineralization but without a clear pattern. The moisture-elevation interaction significantly affected soil C and NO<sub>3</sub><sup>&ndash;</sup>-N mineralization, but the effect on NH<sub>4</sub><sup>+</sup>-N mineralization was not significant. The complex mechanism of their impact on the soil C and N mineralization of Changbai Mountain remains to be studied further based on data of field measurements in the future. &nbsp;

Grassland soil carbon and nitrogen stocks under temperate livestock grazing

Soil Research ◽  
2015 ◽  
Vol 53 (5) ◽  
pp. 485 ◽  
Author(s):  
Junfang Cui ◽  
Mohammad Sadegh Askari ◽  
Nicholas M. Holden
Keyword(s):  
Livestock Grazing ◽  
Intensive Management ◽  
Stocking Rate ◽  
Clay Loam ◽  
N Content ◽  
Soil C ◽  
Management Intensity ◽  
Soil C And N ◽  
C And N ◽  
Grass Sward

Sustainable grassland management is critical to many agricultural economies because of the significant proportion of agricultural commodities derived from grass-fed livestock (milk and meat). Mismanagement will result in a cycle of soil quality deterioration and reduced productivity. This study estimated carbon (C) and nitrogen (N) stocks in relation to grazing management in Ireland, with a focus on understanding the role of management intensity derived from the interaction of stocking rate, N fertiliser rate and reseeding frequency. Soil samples were taken from depths 0–10, 10–20 and 20–30 cm. Soil physical properties, C and N concentrations, and microbial biomass C were measured. Significant increases in C and N concentrations were observed along the texture gradient: sandy loam < loam < sandy clay loam < clay loam < silty clay loam. However, there was little difference in C and N stock according to soil texture class. Soil with 10–20-year-old grass sward contained the lowest soil C and N content, indicating that proper reseeding is necessary to maintain soil C and N storage capacity. Increased chemical N fertiliser rate did not cause changes of soil C and N content, whereas intensified stocking rate caused great changes in soil C and N content by re-locating soil C and N at depth. Moderately intensive management was associated with significantly lower C and N stocks, and highly intensive management was associated with greater capacity of soil C and N, but no interaction between texture and management intensity was found.

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