Dynamics of microbial-C, N-flush and ATP, and enzyme activities of gradually dried soils from a climosequence

Soil Research ◽  
1988 ◽  
Vol 26 (3) ◽  
pp. 519 ◽  
Author(s):  
AW West ◽  
GP Sparling ◽  
TW Speir ◽  
JM Wood
Keyword(s):  
Annual Rainfall ◽  
Silt Loam ◽  
Strongly Correlated ◽  
Total Change ◽  
Moisture Regimes ◽  
Substrate Induced Respiration ◽  
C And N ◽  
Microbial C ◽  
Soil Phosphatase ◽  
Microbial N

Three silt loam soils from a climosequence (1000-2700 mm annual rainfall) were gradually dried from field moisture content to air-dryness at 25�C in the laboratory. Microbial C measured by substrate-induced respiration (SIR), fumigation-incubation (FI) or fumigation-extraction (FE), microbial N-flush measured by FI and FE, microbial ATP content and soil phosphatase and sulfatase activities were monitored throughout the drying period (approx. 60 h). All indices declined as the gravimetric soil water content (W) decreased until reaching air-dryness. Significant declines in the biomass sometimes occurred only following a large decrease in W, dependent on the soil. In general, when microbial C and N-flush declined, the rates of decline were linearly correlated with W. However, ATP and soil phosphatase were exponentially related to W. When expressed as a ratio of the total change in microbial indices against the total change in W for the whole drying period, the ratios were consistent between the soils. Agreement between the SIR and FE estimates of microbial C, whilst significant (r = 0 58***), was poor, especially for the low rainfall soil, although the FE C- and N-flushes correlated well (r = 0-76***). In contrast, the FI C- and N-flushes correlated very poorly (r = 0.30**) and were not significantly correlated with W or the other indices. ATP and soil phosphatase activity were strongly correlated (r = 0.89***). The reliability of the methods and the influence of soil moisture regimes on microbial survival are discussed.

Comparison of microbial C, N-flush and ATP, and certain enzyme activities of different textured soils subject to gradual drying

Soil Research ◽  
1988 ◽  
Vol 26 (1) ◽  
pp. 217 ◽  
Author(s):  
AW West ◽  
GP Sparling ◽  
TW Speir ◽  
JM Wood
Keyword(s):  
Soil Texture ◽  
Clay Loam ◽  
Fe Method ◽  
Wide Range ◽  
Loam Soil ◽  
Substrate Induced Respiration ◽  
C And N ◽  
Microbial C ◽  
The Relationship ◽  
Microbial N

A clay loam, a silt loam and a sand soil were gradually dried from field moisture content to air-dryness at 25�C in the laboratory. Microbial C measured by substrate-induced respiration (SIR), fumigation-incubation (FI) and fumigation-extraction (FE), microbial N-flush measured by FI and FE, microbial ATP content, and soil phosphatase and sulfatase activities were monitored throughout a drying period of approx. 60 h achieved over 16 days. All the microbial and enzyme variables declined as the gravimetric soil water content ( W) decreased to air-dryness. In general, the relationship between microbial C or N-flush and W was linear, but was exponential between ATP or phosphatase and W. Soil texture appeared to affect the rates of decline and also the amounts of the microbial and enzyme variables remaining in air-dry soil; e.g., the lowest rate of microbial C decline and the largest amount remaining at air-dryness occurred in the clay loam soil. Sulfatase activity was not significantly affected by soil drying. Agreement between the SIR and FE estimates of microbial C was good (r = 0.92***). These two methods were applicable over a wide range of water contents. Microbial N-flush, estimated by the FE method, also showed a consistent trend and correlated highly with microbial C estimated by SIR or FE. In contrast, microbial C and N-flush estimated by the FI method were not significantly correlated with W or any of the other variables. ATP and phosphatase activity appeared to relate more closely to microbial activity (CO2 respiration/microbial C) than microbial mass. The reliability of the methods to measure the biomass and the influence of soil texture, water and carbon contents on microbial survival are discussed.

Microbial activity in gradually dried or rewetted soils as governed by water and substrate availability

Soil Research ◽  
1989 ◽  
Vol 27 (4) ◽  
pp. 747 ◽  
Author(s):  
AW West ◽  
GP Sparling ◽  
TW Speir
Keyword(s):  
Microbial Respiration ◽  
Annual Rainfall ◽  
Silt Loam ◽  
Moisture Regimes ◽  
Substrate Induced Respiration ◽  
Qualitative Nature ◽  
Micro Organisms ◽  
Gravimetric Water Content ◽  
Microbial Mass ◽  
Better Than

Microbial respiration, mass and activity (respiration/mass) in three silt loam soils with different moisture regimes (1000-2700 mm annual rainfall) were measured as the field-moist soils were gradually air-dried at 25�C in the laboratory. Microbial CO2 and O2 respiration and mass (estimated from substrate-induced respiration), and oxidizable organic carbon, extractable in 0.5 M K2SO4, were monitored throughout the 60 h drying period and also in samples of these gradually dried soils which were rewetted with water (2 ml g-1 soil). Water availability was the major factor controlling microbial respiration and activity as the soils dried. Both respiration and activity declined continuously as gravimetric water content (W) decreased. Microbial mass also declined, but only after W fell below 0.1-0.3. The microbial mass of the lowest-rainfall soil resisted desiccation better than the higher-rainfall soils. Extractable carbon levels increased after considerable soil drying (when W < 0.1-0.2). This increase in extractable carbon could be accounted for by the carbon released from micro-organisms killed by drying. Microbial respiration and activity increased sharply within 30 min of rewetting gradually dried soils. These increases appeared to be largely due to the carbon released from micro-organisms, killed by drying, being metabolized by the surviving micro-organisms when water was present. The ability of the surviving micro-organisms to metabolize this (extractable) carbon was remarkably similar for all three soils, suggesting that the carbon released from killed cells is of a very similar qualitative nature, and/or that the surviving populations were also similar between the soils.

scholarly journals Preferential protein depolymerization as a preservation mechanism for vascular litter decomposing in <i>Sphagnum</i> peat

2019 ◽  
Author(s):  
Hendrik Reuter ◽  
Julia Gensel ◽  
Marcus Elvert ◽  
Dominik Zak
Keyword(s):  
Protein Content ◽  
Litter Breakdown ◽  
N Dynamics ◽  
N Content ◽  
Sphagnum Peat ◽  
Elemental Analyses ◽  
Microbial Carbon ◽  
C And N ◽  
Microbial C ◽  
Microbial N

Abstract. Nitrogen (N) dynamics in Phragmites australis litter due to anaerobic decomposition in three anoxic wetland substrates were analyzed by elemental analyses and infrared spectroscopy (FTIR). After 75 days of decomposition, a relative accumulation of bulk N was detected in most litters, but N accumulated less when decomposition took place in a more N-poor environment. FTIR was used to quantify the relative content of proteins in litter tissue and revealed a highly linear relationship between bulk N content and protein content. Changes in bulk N content thus paralleled and probably were governed by changes in litter protein content. Such changes are the result of two competing processes within decomposing litter: enzymatic protein depolymerization as a part of the litter breakdown process and microbial protein synthesis as a part of microbial biomass growth within the litter. Assuming microbial homeostasis, DNA signals in FTIR spectra were used to calculate the amount of microbial N in decomposed litter which ranged from 14 to 42 % of the total litter N for all leaf samples. Microbial carbon (C) content and resultant calculated carbon-use efficiencies (CUEs) indicate that microbial N in litter accumulated according to predictions of the stoichiometric decomposition theory. Subtracting microbial C- and N-contributions from litter, however, revealed decomposition site dependent variations in the percentual amount of remaining, still unprocessed plant N compared to remaining plant C, an indicator for preferential protein depolymerization. For all leaf litters, the coefficient of preferential protein depolymerization (α), which relates N-compound depolymerization to C-compound depolymerization, ranged from 0.74–0.88 in a nutrient-rich detritus mud to 1.38–1.82 in Sphagnum peat, the most nutrient-poor substrate in this experiment. Preferential protein depolymerization leads to a gradual N depletion of decomposing litter which we propose as a preservation mechanism for vascular litter decomposing in Sphagnum peat.

Soil microbial biomass and microbial and mineralizable N in a clear-cut chronosequence on northern Vancouver Island, British Columbia

1995 ◽  
Vol 25 (10) ◽  
pp. 1595-1607 ◽  
Author(s):  
Scott X. Chang ◽  
Gordon F. Weetman ◽  
Caroline M. Preston
Keyword(s):  
Microbial Biomass ◽  
Vancouver Island ◽  
Old Growth ◽  
Clear Cutting ◽  
Old Growth Forest ◽  
Mineralizable N ◽  
Old Growth Forests ◽  
C And N ◽  
Microbial C ◽  
Microbial N

We studied the dynamics of microbial biomass and nitrogen in old-growth forests and in 3- and 10-year-old plantations established after clear-cutting and slash burning of old-growth western red cedar (Thujaplicata Donn ex D. Don)–western hemlock (Tsugaheterophylla (Raf.) Sarg.) stands on northern Vancouver Island. Ten-year-old plantations, after initially growing well, were experiencing declining growth rates. Three forest floor layers: F (fermentation), woody F (Fw), and H (humus) were sampled four times in May, July, August, and October of 1992. Moisture content was significantly greater in the old-growth forests than in the plantations for F on July 16 (p < 0.05) and Fw (p < 0.10), but was not significantly different for H. Microbial biomass C and N were relatively constant throughout the sampling period, resulting in nonsignificant date effects. Microbial C content was in the order: old-growth forests > 10-year-old plantations > 3-year-old plantations. Microbial N content was significantly greater in the old-growth forest than in the young plantations for both F (p < 0.001) and H (p < 0.05) but was not different between the plantations. Therefore, the hypothesis that the microbial biomass acted as a net sink in the 10-year-old plantations by immobilizing N into the microbial N pool is rejected. Microbial C/N ratios were greater (p < 0.05) in the 10-year-old plantations than in the old-growth forests and in the 3-year-old plantations in H and on July 16 in F, indicating that microbial competition for N was probably a factor in the growth declining in the 10-year-old plantations. Extractable C and N and mineralizable N were generally higher in the old-growth forests than in the 3-year-old plantations and higher in the 3-year-old than in the 10-year-old plantations. As a result of better nutritional conditions, tree and understory foliage in the 3-year-old plantations had higher N concentrations and lower C/N ratios than in the 10-year-old plantations. Trees in the 10-year-old plantations displayed chlorotic symptoms and slow growth which were not observed in the 3-year-old plantations.

scholarly journals Evidence for preferential protein depolymerization in wetland soils in response to external nitrogen availability provided by a novel FTIR routine

2020 ◽  
Vol 17 (2) ◽  
pp. 499-514 ◽  
Author(s):  
Hendrik Reuter ◽  
Julia Gensel ◽  
Marcus Elvert ◽  
Dominik Zak
Keyword(s):  
Protein Content ◽  
Nitrogen Availability ◽  
Nutrient Status ◽  
Wetland Soils ◽  
N Content ◽  
Sphagnum Peat ◽  
Microbial Carbon ◽  
C And N ◽  
Microbial C ◽  
Microbial N

Abstract. Phragmites australis litters were incubated in three waterlogged anoxic wetland soils of different nutrient status for 75 d, and litter nitrogen (N) dynamics were analyzed by elemental analyses and Fourier transform infrared spectroscopy (FTIR). At the end of the incubation time, the N content in the remaining litter tissue had increased in most samples. Yet, the increase in N content was less pronounced when litters had been decomposed in a more-N-poor environment. FTIR was used to quantify the relative content of proteins in litter tissue and revealed a highly linear relationship between bulk N content and protein content. Changes in bulk N content thus paralleled and probably were governed by changes in litter protein content. Such changes are the result of two competing processes within decomposing litter: enzymatic protein depolymerization as a part of the litter breakdown process and microbial protein synthesis as a part of microbial biomass growth within the litter. Assuming microbial homeostasis, DNA signals in FTIR spectra were used to calculate the amount of microbial N in decomposed litter which ranged from 14 % to 42 % of the total litter N for all leaf samples. Microbial carbon (C) content and resultant calculated carbon use efficiencies (CUEs) indicate that microbial N in litter accumulated according to predictions of the stoichiometric decomposition theory. Subtracting microbial C and N contributions from litter, however, revealed site-dependent variations in the percentual amount of the remaining still-unprocessed plant N in litter compared to remaining plant C, an indicator for preferential protein depolymerization. For all leaf litters, the coefficient of preferential protein depolymerization (α), which relates N-compound depolymerization to C-compound depolymerization, ranged from 0.74–0.88 in a nutrient-rich detritus mud to 1.38–1.82 in Sphagnum peat, the most nutrient-poor substrate in this experiment. Preferential protein depolymerization from litter decomposing in Sphagnum peat leads to a gradual N depletion in the early phase of litter decomposition, which we propose as a preservation mechanism for vascular litter in Sphagnum peatlands.

THE ROLE OF GRASSLAND IN MANAGEMENT

1968 ◽  
pp. 44-49
Author(s):  
B.K. Cameron
Keyword(s):  
Soil Temperature ◽  
Annual Rainfall ◽  
Silt Loam ◽  
Average Annual Rainfall ◽  
Very High ◽  
Wilting Point

THE PROPERTY to be discussed is a mixed sheep and cropping unit, situated ei ht a miles east of Ashburton and midway between the Ra aia and the Ashburton rivers. Average annual rainfall is 27 in., evenly spread, but there is very high summer evaporation and therefore frequent droughts. On average, the soil is below wilting point for 40 to 50 days each summer. Winters are cold with the soil temperature being below 48°F for about four months each year. The soil is a Lismore stony silt loam averaging 9 in. in depth over gravel.

Variation in the morphology and flowering time of cluster clover (Trifolium glomeratum L.) and its relationship to distribution in southern Australia

1995 ◽  
Vol 46 (5) ◽  
pp. 1027 ◽  
Author(s):  
FP Smith ◽  
PS Cocks ◽  
MA Ewing
Keyword(s):  
Genetic Variation ◽  
Flowering Time ◽  
Seed Mass ◽  
Annual Rainfall ◽  
Strongly Correlated ◽  
Summer Maximum ◽  
Maximum Temperatures ◽  
Pattern Of Variation ◽  
Growth Habits

Cluster clover is a widely distributed and ecologically successful introduced legume in southern Australia. In an attempt to understand the role of genetic variation in this success, morphological and physiological traits were measured in 94 accessions from southern Australia and 6 from the Mediterranean basin. Flowering time ranged from 105 to 185 days after sowing, but was not strongly correlated with annual rainfall or length of growing season at the site of collection. Variation in other traits partitioned the populations into two morphs which, apart from flowering time and leaf marker, were largely homogeneous. The morphs differed significantly in floret number per inflorescence (22 v. 32-37) and seed mass (379 8g v. 523 8g), had different growth habits and strong within-morph associations between leaf markers and stipule and petal coloration. The morphs differed in their distributions within southern Australia and the pattern of distribution was related to summer maximum temperatures, winter minimum temperatures and spring rainfall. These results demonstrate that genetic variation has been important to the success of cluster clover and suggests that the variation is organized. The pattern of variation observed and its relationship to ecogeography is consistent with findings for other highly inbreeding species. A map of the species distribution in Western Australia is presented.

scholarly journals Soil carbon and nitrogen erosion in forested catchments: implications for erosion-induced terrestrial carbon sequestration

2015 ◽  
Vol 12 (16) ◽  
pp. 4861-4874 ◽  
Author(s):  
E. M. Stacy ◽  
S. C. Hart ◽  
C. T. Hunsaker ◽  
D. W. Johnson ◽  
A. A. Berhe
Keyword(s):  
Organic Matter ◽  
Sierra Nevada ◽  
Sediment Yield ◽  
Forest Ecosystems ◽  
Mineral Particle ◽  
Strongly Correlated ◽  
Terrestrial Carbon ◽  
Stream Discharge ◽  
C And N ◽  
Sediment Export

Abstract. Lateral movement of organic matter (OM) due to erosion is now considered an important flux term in terrestrial carbon (C) and nitrogen (N) budgets, yet most published studies on the role of erosion focus on agricultural or grassland ecosystems. To date, little information is available on the rate and nature of OM eroded from forest ecosystems. We present annual sediment composition and yield, for water years 2005–2011, from eight catchments in the southern part of the Sierra Nevada, California. Sediment was compared to soil at three different landform positions from the source slopes to determine if there is selective transport of organic matter or different mineral particle size classes. Sediment export varied from 0.4 to 177 kg ha−1, while export of C in sediment was between 0.025 and 4.2 kg C ha−1 and export of N in sediment was between 0.001 and 0.04 kg N ha−1. Sediment yield and composition showed high interannual variation. In our study catchments, erosion laterally mobilized OM-rich litter material and topsoil, some of which enters streams owing to the catchment topography where steep slopes border stream channels. Annual lateral sediment export was positively and strongly correlated with stream discharge, while C and N concentrations were both negatively correlated with stream discharge; hence, C : N ratios were not strongly correlated to sediment yield. Our results suggest that stream discharge, more than sediment source, is a primary factor controlling the magnitude of C and N export from upland forest catchments. The OM-rich nature of eroded sediment raises important questions about the fate of the eroded OM. If a large fraction of the soil organic matter (SOM) eroded from forest ecosystems is lost during transport or after deposition, the contribution of forest ecosystems to the erosion-induced C sink is likely to be small (compared to croplands and grasslands).

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

2003 ◽  
Vol 60 (1) ◽  
pp. 139-147 ◽  
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.

Release of ninhydrin-reactive compounds during fumigation of soil to estimate microbial C and N

1993 ◽  
Vol 25 (12) ◽  
pp. 1803-1805 ◽  
Author(s):  
G.P. Sparlig ◽  
V.V.S.R. Gupta ◽  
Chunya Zhu
Keyword(s):  
C And N ◽  
Microbial C
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