Poind Soil pH Measurement

Thunjai, Taworn; Boyd, Claude E.; Dube, Karen

doi:10.1111/j.1749-7345.2001.tb00365.x

Cited by 47 publications

(19 citation statements)

References 5 publications

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“…Total C and nitrogen (N) concentrations and the δ 13 C values of milled subsamples were quantified with a Finnigan Delta Plus‐XL mass spectrometer; δ 13 C results are reported as per mil () deviations from the V‐PDB standard for carbon (Bird et al ., 2007). pH was measured with an electrode in a mixture of dry soil and 0.01 m CaCl 2 at a ratio of 1:10 after shaking the mixture for 17 hours (Thunjai et al ., 2001). Particle size analyses for all mineral layers were determined by laser diffraction (Beckmann Coulter LS230, Krefeld, Germany).…”

Section: Methodsmentioning

confidence: 99%

Climate dependence of heterotrophic soil respiration from a soil‐translocation experiment along a 3000 m tropical forest altitudinal gradient

Zimmermann

Meir

Bird

et al. 2009

European J Soil Science

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Summary Tropical ecosystems play a key role in the global carbon cycle, but their response to global warming is not well understood. Altitudinal gradients offer the unique possibility of undertaking in situ experimental studies of the influence of alterations in climate on the carbon (C) cycle. In a soil‐translocation experiment we took replicate soil cores at 3030 m, 1500 m, 1000 m and 200 m above sea level along an altitudinal gradient in tropical forest in Peru, and exchanged (i.e. translocated) them among these sites to observe the influence of altered climatic conditions on the decomposition of soil organic matter under natural field conditions. Soil respiration rates of the translocated soil cores and adjacent undisturbed soils were measured twice a month from April 2007 to October 2007. The temperature sensitivity of heterotrophic respiration in each core was examined using a Lloyd & Taylor function and a simple modified third‐order polynomial fit. Calculated Q10 values decreased with decreasing altitude using both mathematical functions (2.53–1.24 according to the Lloyd & Taylor function, and 2.56–0.63 using the polynomial fit). Soil organic C‐stocks increased markedly and linearly with altitude, but surprisingly the average total soil respiration rate did not vary significantly with altitude along the transect (3.98–4.31 μmol CO2 m−2 s−1). This implies an increase with elevation of absolute C allocation to below‐ground allocation.

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Section: Methodsmentioning

confidence: 99%

Climate dependence of heterotrophic soil respiration from a soil‐translocation experiment along a 3000 m tropical forest altitudinal gradient

Zimmermann

Meir

Bird

et al. 2009

European J Soil Science

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“…Soil pH was measured with a glass electrode inserted into a 1:1 mixture of dry, pulverized soil and distilled water (Thunjai, Boyd & Dube 2001). Exchange acidity was measured from the pH change in a solution containing 20‐g soil and 40‐mL buffer.…”

Section: Methodsmentioning

confidence: 99%

Bottom soil quality in Tilapia ponds of different age in Thailand

Thunjai¹,

Boyd²,

Boonyaratpalin³

2004

Aquac Research

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Bottom soil samples were collected from 35 ponds in the vicinity of Samutprakarn, Thailand. Ponds ranged in age from 3 to 39 years and had been used continuously for production of tilapia. Liming materials had been applied in large amounts, and bottom soils of all ponds had pH above 7, low exchange acidity, and free carbonate. Pond soils often contained between 1% and 2% total sulphur, suggesting that they were potential acid–sulphate soils. However, acidity from sulphide oxidation was not expressed because carbonate in the soil neutralized it. Concentrations of total carbon seldom exceeded 4% and the average for organic carbon was 1.90%. The correlations between pond age and both total carbon and organic carbon concentration were weak (r=0.34 and 0.36 respectively). Concentrations of nitrogen in bottom soils did not differ with pond age and ranged from 0.1% to 0.3% with an average of 0.19%. The average ratio of concentrations of carbon and nitrogen was 11. Acid‐extractable phosphorus concentrations averaged 217 mg kg−1, but the phosphorus adsorption capacity averaged 768 mg kg−1 suggesting that soils still have considerable reserve capacity to adsorb phosphorus. Ponds can be used annually for semi‐intensive production of tilapia, and presumably other species, for many years without serious deterioration of bottom soil quality.

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“…Sediment pH and salinity were measured from samples of volume of 63.6 cm 3 that were collected from each site with three replicates each at the time of benthic foraminifera sample collection following the methods of Taworn and Boyd [29, 30], in which the dried sediment is resuspended in distilled water and the resulting pH and salinity are measured in the supernatant. These replicates were taken about 5 cm apart from the foraminifera sampling points.…”

Section: Methodsmentioning

confidence: 99%

Seasonal and Spatial Variations of Saltmarsh Benthic Foraminiferal Communities from North Norfolk, England

Saad

Wade

2016

Microb Ecol

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Time series foraminiferal data were obtained from samples collected from three sites at Brancaster Overy Staithe, Burnham Overy Staithe and Thornham on the North Norfolk coast over a 1-year period. At each collection point, six environmental variables—temperature, chlorophyll, sand, mud, pH and salinity—were also measured. The principle aim of this study was to examine the benthic foraminiferal fauna in regard to the temporal variability of foraminiferal abundance, seasonal trend, dominant species, species diversity and the impact of environmental variables on the foraminiferal communities in the top 1 cm of sediment over a 1-year time series. The foraminiferal assemblages at the three sites were dominated by three species: Haynesina germanica, Ammonia sp. and Elphidium williamsoni. Foraminiferal species showed considerable seasonal and temporal fluctuation throughout the year at the three investigated sites. The foraminiferal assemblage at the three low marsh zones showed a maximum abundance in autumn between September and November and a minimum abundance observed between July and August. There were two separate peaks in the abundance of Ammonia sp. and E. williamsoni, one in spring and another in autumn. In contrast, H. germanica showed a single peak in its abundance in autumn. A generalized additive modelling approach was used to explain the variation in the observed foraminiferal abundance and to estimate the significant impact of each of the environmental variables on living foraminiferal assemblages, with taxa abundance as the dependent variable. When included in the model as predictors, most of the environmental variables contributed little in explaining the observed variation in foraminiferal species abundance. However, the hypotheses for differences amongst sites, salinity and pH were significant and explained most of the variability in species relative abundance.Electronic supplementary materialThe online version of this article (doi:10.1007/s00248-016-0895-5) contains supplementary material, which is available to authorized users.

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Poind Soil pH Measurement

Cited by 47 publications

References 5 publications

Climate dependence of heterotrophic soil respiration from a soil‐translocation experiment along a 3000 m tropical forest altitudinal gradient

Climate dependence of heterotrophic soil respiration from a soil‐translocation experiment along a 3000 m tropical forest altitudinal gradient

Bottom soil quality in Tilapia ponds of different age in Thailand

Seasonal and Spatial Variations of Saltmarsh Benthic Foraminiferal Communities from North Norfolk, England

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