Relationships between extractable Al, selected soil properties, pH buffer capacity and lime requirement in some acidic Queensland soils

Soil Research ◽  
1992 ◽  
Vol 30 (2) ◽  
pp. 119 ◽  
Author(s):  
RL Aitken
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Soil Properties ◽  
Buffer Capacity ◽  
Clay Content ◽  
Ph Buffering ◽  
Ph Buffer ◽  
Mineral Soils ◽  
Chloride Salts ◽  
Hydrolysis Of

The objectives of this study were to examine (1) interrelationships between various forms of extractable A1 and selected soil properties, (2) the contribution of extractable A1 to pH buffer capacity, and (3) investigate the use of extractable A1 to predict lime requirement. Aluminium was extracted from each of 60 Queensland soils with a range of chloride salts: 1 M KCl (AlK), 0.5 M CuCl2 (AlCu), 0.33 M LaCl3 (AlLa) and 0.01 M CaCl2 (AlCa). The amounts of A1 extracted were in the order AlCu > AlLa > Alk > AlCa. Little or no A1 was extracted by KC1 or Lac13 in soils with pHw values greater than 5.5 , whereas CuCl2 extracted some A1 irrespective of soil pH. The greater amounts of A1 extracted by CuCl2 were attributed mainly to A1 from organic matter, even though all of the soils were mineral soils (organic carbon 54.7%). Both AlCu and AlLa, were significantly (P < 0.001) correlated with organic carbon, whereas none of the extractable A1 measures was correlated with clay content. AlK and A~L, were poorly correlated to pH buffer capacity. The linear relationship between AlCu and pH buffer capacity (r2 = 0.49) obtained in this study supports the view of previous researchers that the hydrolysis of A1 adsorbed by organic matter is a source of pH buffering in soils. However, the change in CEC with pH accounted for 76% of the variation in pH buffer capacity, indicating that other mechanisms such as deprotonation of organic groups and variable charge minerals are also involved in pH buffering. The ability of CuCl2 and LaCl3extractable Al to estimate lime requirement depended on the target pH. The results suggest that lime requirements based on neutralization of AlLa would be sufficient to raise pHw to around 5.5, whereas requirements based on neutralization of AlCu substantially overestimated the actual lime requirement to pHw 5.5, but gave a reasonable estimation of the lime requirement to pHw 6 5.

Lime requirement of acidic Queensland soils. I. Relationships between soil properties and pH buffer capacity

Soil Research ◽  
1990 ◽  
Vol 28 (5) ◽  
pp. 695 ◽  
Author(s):  
RL Aitken ◽  
PW Moody ◽  
PG Mckinley
Keyword(s):  
Linear Regression ◽  
Organic Carbon ◽  
Soil Properties ◽  
Multiple Linear Regression ◽  
Multiple Regression ◽  
Buffer Capacity ◽  
Clay Content ◽  
Exchangeable Al ◽  
Ph Buffer ◽  
Exchange Acidity

The pH buffer capacity of 40 acidic surface soils (pHw <6.5) was determined from soil-CaCO3- moist incubations. Buffer capacity values ranged from 02 to 5.4 g CaCO3 kg-1 soil unit-1 pH increase. Organic carbon, clay content, ECEC, 1M KCl extractable acidity and Al, and the change in CEC with pH (�CEC) were measured and correlated with pH buffer capacity. Step-up multiple linear regression indicated that the effect of �CEC on buffer capacity was highly significant (r2 = 0.77, P <0.001), whereas that of exchangeable Al or exchange acidity was not. This suggests that deprotonation reactions, compared with exchangeable Al or exchange acidity, are considerably more important in determining buffer capacity. The major soil property affecting �CEC in our soils was the organic carbon content and, when step-up multiple linear regression was used, �CEC could be best estimated by organic carbon plus clay content plus ECEC (R2 = 0.77, P < 0.001). To ascertain whether exchangeable Al (or exchange acidity) would contribute to buffer capacity in soils with less variable charge, soils of relatively low organic carbon (<2.5%) were considered. For the 33 soils with <2.5% organic carbon, �CEC was still the major determinant of buffer capacity (r2 = 0.76, P <0.001), although inclusion of exchange acidity in a multiple regression with �CEC significantly increased the variance accounted for (R2 = 0.80, P < 0.001). Of the soil properties that could be routinely measured, a multiple regression equation combining organic carbon, clay content and exchange acidity accounted for 85% of the variance in buffer capacity, with organic carbon being the most important.

Predicting pH buffering capacity of New Zealand soils from organic matter content and mineral characteristics

Soil Research ◽  
2013 ◽  
Vol 51 (6) ◽  
pp. 494 ◽  
Author(s):  
Denis Curtin ◽  
Stephen Trolove
Keyword(s):  
Organic Matter ◽  
New Zealand ◽  
Buffer Capacity ◽  
Organic Matter Content ◽  
Clay Content ◽  
Matter Content ◽  
Soil C ◽  
Ph Buffering ◽  
Mineral Characteristics ◽  
Permanent Pasture

Information on the pH buffer capacity of soil is required to estimate changes in pH due to acidic or alkaline inputs, and to model pH-dependent processes within the soil nitrogen (N) cycle. The objective was to determine whether a model based on soil organic matter (SOM) and mineral characteristics (clay content, extractable iron (Fe) and aluminium (Al)) would be adequate to estimate the buffer capacities of New Zealand soils. We measured pH changes in 34 soils, representing a range of SOM and texture, after equilibration with several rates (range 0–15 cmol OH– kg–1 soil) of either KOH or Ca(OH)2. The Ca(OH)2 method often yielded higher buffer capacity values than the KOH method, possibly because of incomplete reaction of Ca(OH)2, especially at high addition rates. Buffer capacity (measured using KOH) of the soils was strongly correlated with soil carbon (C) (R2 = 0.76), and weakly (but significantly, P < 0.05) with clay content, and with dithionite extractable Fe and Al. A regression with soil C, clay, and P-retention (a surrogate for extractable Al and Fe) as independent variables explained 90% of the variability in pH buffering. The role of organic matter was further evaluated by measuring buffer capacity of soil from research plots at Lincoln, Canterbury, New Zealand, that differed in C (21–37 g C kg–1 in the top 7.5 cm; 19–26 g C kg–1 in the 7.5–15 cm) as a result of the treatments imposed during the 12-year trial period. A substantial decrease in pH buffering (by up to 24% in top 7.5 cm) was associated with a decline in SOM following the conversion of permanent pasture (pre-trial land use) to arable cropping. Across all treatments and sampling depths, buffer capacity was linearly related (R2 = 0.84, P < 0.001) to soil C; the estimated buffer capacity of SOM was 89 cmolc kg–1 C pH unit–1, similar to the value calculated from the previous study with different soil types. After 12 years, treatments with low soil C concentrations tended to be more acidic, possibly partly because of weaker pH buffering.

scholarly journals Three representative UK moorland soils show differences in decadal release of dissolved organic carbon in response to environmental change

2011 ◽  
Vol 8 (12) ◽  
pp. 3661-3675 ◽  
Author(s):  
M. I. Stutter ◽  
D. G. Lumsdon ◽  
A. P. Rowland
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Environmental Change ◽  
Soil Properties ◽  
Process Models ◽  
Environmental Drivers ◽  
Specific Response ◽  
Soil C ◽  
Doc Concentration ◽  
Mineral Soils

Abstract. Moorland carbon reserves in organo-mineral soils may be crucial to predicting landscape-scale variability in soil carbon losses, an important component of which is dissolved organic carbon (DOC). Surface water DOC trends are subject to a range of scaling, transport and biotic processes that disconnect them from signals in the catchment's soils. Long-term soil datasets are vital to identify changes in DOC release at source and soil C depletion. Here we show, that moorland soil solution DOC concentrations at three key UK Environmental Change Network sites increased between 1993–2007 in both surface- and sub- soil of a freely-draining Podzol (48 % and 215 % increases in O and Bs horizons, respectively), declined in a gleyed Podzol and showed no change in a Peat. Our principal findings were that: (1) considerable heterogeneity in DOC response appears to exist between different soils that is not apparent from the more consistent observed trends for streamwaters, and (2) freely-draining organo-mineral Podzol showed increasing DOC concentrations, countering the current scientific focus on soil C destabilization in peats. We discuss how the key solubility controls on DOC associated with coupled physico-chemical factors of ionic strength, acid deposition recovery, soil hydrology and temperature cannot readily be separated. Yet, despite evidence that all sites are recovering from acidification the soil-specific responses to environmental change have caused divergence in soil DOC concentration trends. The study shows that the properties of soils govern their specific response to an approximately common set of broad environmental drivers. Key soil properties are indicated to be drainage, sulphate and DOC sorption capacity. Soil properties need representation in process-models to understand and predict the role of soils in catchment to global C budgets. Catchment hydrological (i.e. transport) controls may, at present, be governing the more ubiquitous rises in river DOC concentration trends, but soil (i.e. source) controls provide the key to prediction of future C loss to waters and the atmosphere.

scholarly journals Relationship between soil oxidizable carbon and physical, chemical and mineralogical properties of umbric ferralsols

2011 ◽  
Vol 35 (1) ◽  
pp. 25-40 ◽  
Author(s):  
Flávio Adriano Marques ◽  
Márcia Regina Calegari ◽  
Pablo Vidal-Torrado ◽  
Peter Buurman
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Clay Content ◽  
Selective Extraction ◽  
Total Carbon ◽  
Soil Matrix ◽  
Soil Variables ◽  
Physical Chemical ◽  
Mineralogical Properties ◽  
Extractable Al

The occurrence of Umbric Ferralsols with thick umbric epipedons (> 100 cm thickness) in humid Tropical and Subtropical areas is a paradox since the processes of organic matter decomposition in these environments are very efficient. Nevertheless, this soil type has been reported in areas in the Southeast and South of Brazil, and at some places in the Northeast. Aspects of the genesis and paleoenvironmental significance of these Ferralsols still need a better understanding. The processes that made the umbric horizons so thick and dark and contributed to the preservation of organic carbon (OC) at considerable depths in these soils are of special interest. In this study, eight Ferralsols with a thick umbric horizon (UF) under different vegetation types were sampled (tropical rain forest, tropical seasonal forest and savanna woodland) and their macromorphological, physical, chemical and mineralogical properties studied to detect soil characteristics that could explain the preservation of high carbon amounts at considerable depths. The studied UF are clayey to very clayey, strongly acidic, dystrophic, and Al-saturated and charcoal fragments are often scattered in the soil matrix. Kaolinites are the main clay minerals in the A and B horizons, followed by abundant gibbsite and hydroxyl-interlayered vermiculite. The latter was only found in UFs derived from basalt rock in the South of the country. Total carbon (TC) ranged from 5 to 101 g kg-1 in the umbric epipedon. Dichromate-oxidizable organic carbon represented nearly 75 % of TC in the thick A horizons, while non-oxidizable C, which includes recalcitrant C (e.g., charcoal), contributed to the remaining 25 % of TC. Carbon contents were not related to most of the inorganic soil variables studied, except for oxalate-extractable Al, which individually explained 69 % (P < 0.001) of the variability of TC in the umbric epipedon. Clay content was not suited as predictor of TC or of the other studied C forms. Bulk density, exchangeable Al3+, Al saturation, ECEC and other parameters obtained by selective extraction were not suitable as predictors of TC and other C forms. Interactions between organic matter and poorly crystalline minerals, as indicated by oxalate-extractable Al, appear to be one of the possible organic matter protection mechanisms of these soils.

scholarly journals Relationship of soil properties to fractionation, bioavailability and mobility of lead and zinc in soil

2008 ◽  
Vol 53 (No. 5) ◽  
pp. 225-238 ◽  
Author(s):  
N. Finžgar ◽  
P. Tlustoš ◽  
D. Leštan
Keyword(s):  
Organic Matter ◽  
Regression Analysis ◽  
Soil Organic Matter ◽  
Soil Properties ◽  
Multiple Regression ◽  
Contaminated Soils ◽  
Organic Matter Content ◽  
Clay Content ◽  
Exchange Capacity ◽  
Matter Content

Sequential extractions, metal uptake by <i>Taraxacum officinale</i>, Ruby&rsquo;s physiologically based extraction test (PBET) and toxicity characteristic leaching procedure (TCLP), were used to assess the risk of Pb and Zn in contaminated soils, and to determine relationships among soil characteristics, heavy metals soil fractionation, bioavailability and leachability. Regression analysis using linear and 2nd order polynomial models indicated relationships between Pb and Zn contamination and soil properties, although of small significance (<i>P</i> < 0.05). Statistically highly significant correlations (<i>P</i> < 0.001) were obtained using multiple regression analysis. A correlation between soil cation exchange capacity (CEC) and soil organic matter and clay content was expected. The proportion of Pb in the PBET intestinal phase correlated with total soil Pb and Pb bound to soil oxides and the organic matter fraction. The leachable Pb, extracted with TCLP, correlated with the Pb bound to carbonates and soil organic matter content (<i>R</i><sup>2</sup> = 69%). No highly significant correlations (<i>P</i> < 0.001) for Zn with soil properties or Zn fractionation were obtained using multiple regression.

Soil organic carbon, permanganate fractions, and the chemical properties of acidic soils

Soil Research ◽  
1997 ◽  
Vol 35 (6) ◽  
pp. 1301 ◽  
Author(s):  
P. W. Moody ◽  
S. A. Yo ◽  
R. L. Aitken
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Chemical Properties ◽  
Soil Chemical Properties ◽  
Multiple Regression Equation ◽  
Organic C ◽  
Wide Range ◽  
Single Addition ◽  
Ph Buffer ◽  
Charge Curve

Total organic carbon (TC) in 32 acidic surface (0–10 cm) soils was divided into 3 fractions (C1, C2, and C3) based on oxidisability by different strengths of KMnO4 (33 mM and 167 mM). With the methodology used, ease of oxidation decreased in the order C1>C2>C3. Several fundamental soil chemical properties were also determined, i.e. ECEC, CEC at pH 6·5 (CEC6·5), slope of the charge curve (ΔCEC), pH buffer capacity, (pHBC), P sorption capacity using a single addition index (PSI150), and content of organically complexed Al. All soils had pH (1:5 water) <6·5, and comprised a wide range of soil types and clay contents. Multiple step-up regression indicated that C fractions were significantly (P < 0·05) correlated with ECEC, ΔCEC, CEC6·5, and pHBC. These results reinforce the critical importance of soil organic matter to the fundamental soil chemical properties of predominantly variable charge soils. The intercorrelations between the various oxidisable C fractions made it difficult to elucidate if degree of oxidisability had any bearing on the reactivity of the organic matter. ECEC was primarily correlated with C1, whereas all C fractions had highly significant (P < 0·01) effects on ΔCEC and pHBC. The fraction which was most difficult to oxidise, C3, made a significant (P < 0·01) contribution to CEC6·5 when combined with clay and ECEC in a multiple regression equation. Generally, one or other of the C fractions was better correlated with the fundamental soil chemical properties than TC. This simple empirical fractionation of soil organic C may therefore be a useful tool for assessing the effects of soil management on these properties.

scholarly journals Mineralization of soil organic nitrogen under waterlogged conditions in relation to other properties of tropical rice soils

Soil Research ◽  
1983 ◽  
Vol 21 (2) ◽  
pp. 133 ◽  
Author(s):  
KL Sahrawat
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Soil Properties ◽  
Total Nitrogen ◽  
Organic Nitrogen ◽  
Wetland Rice ◽  
Organic Carbon Content ◽  
Rice Soils ◽  
Wide Range ◽  
Mineralizable Nitrogen

The mineralizable nitrogen pool in wetland rice soils plays a dominant role in the nitrogen nutrition of rice even in fertilized paddies. There is a lack of information on how different soil properties affect ammonification of organic nitrogen in wetland rice soils. Surface samples of 39 diverse Philippine soils representing a wide range of pH, organic matter and texture were studied to determine the relationships between ammonification of organic nitrogen and soil properties. Simple correlation analysis showed that ammonium production was correlated highly significantly with total nitrogen (r = 0.94**), organic carbon (r = 0.91**) and C/N ratio (r = -0.46**), but it was not significantly correlated with cation exchange capacity, clay or pH. Multiple regression analayses showed that organic matter (organic carbon and total nitrogen) accounted for most of the variation in mineralizable nitrogen. These results suggest that organic carbon content is a good index of mineralizable nitrogen in tropical wetland rice soils.

scholarly journals Three representative UK moorland soils show differences in decadal release of dissolved organic carbon in response to environmental change

2011 ◽  
Vol 8 (4) ◽  
pp. 7823-7857
Author(s):  
M. I. Stutter ◽  
D. G. Lumsdon ◽  
A. P. Rowland
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Environmental Change ◽  
Soil Properties ◽  
Process Models ◽  
Environmental Drivers ◽  
Specific Response ◽  
Soil C ◽  
Doc Concentration ◽  
Mineral Soils

Abstract. Moorland carbon reserves in organo-mineral soils may be crucial to predicting landscape-scale variability in soil carbon losses, an important component of which is dissolved organic carbon (DOC). Surface water DOC trends are subject to a range of scaling, transport and biotic processes that disconnect them from signals in the catchment's soils. Long-term soil datasets are vital to identify changes in DOC release at source and soil C depletion. Here we show, that moorland soil solution DOC concentrations at three key UK Environmental Change Network sites increased between 1993–2007 in both surface- and sub- soil of a freely-draining Podzol (48 % and 215 % increases in O and Bs horizons, respectively), declined in a gleyed Podzol and showed no change in a Peat. Our principal findings were that: (1) considerable heterogeneity in DOC response appears to exist between different soils that is not apparent from the more consistent observed trends for streamwaters, and (2) freely-draining organo-mineral Podzol showed increasing DOC concentrations, countering the current scientific focus on soil C destabilization in peats. We discuss how the key solubility controls on DOC associated with coupled physico-chemical factors of ionic strength, acid deposition recovery, soil hydrology and temperature cannot readily be separated. Yet, despite evidence that all sites are recovering from acidification the soil-specific responses to environmental change have caused divergence in soil DOC concentration trends. The study shows that the properties of soils govern their specific response to an approximately common set of broad environmental drivers. Key soil properties are indicated to be drainage, sulphate and DOC sorption capacity. Soil properties need representation in process-models to understand and predict the role of soils in catchment to global C budgets. Catchment hydrological (i.e. transport) controls may, at present, be governing the more ubiquitous rises in river DOC concentration trends, but soil (i.e. source) controls provide the key to prediction of future C loss to waters and the atmosphere.

Growth of Legume Cover Crops under Cassava and Its Effect on Soil Properties

2021 ◽  
Author(s):  
Suwarto . ◽  
Retno Asih
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Properties ◽  
Cover Crops ◽  
Cover Crop ◽  
Soil Moisture Content ◽  
Legume Cover Crops ◽  
Calopogonium Mucunoides ◽  
Legume Cover Crop

Background: Low soil organic carbon is a constraint to cassava tuber formation. Some legume cover crops could be an alternative to provide organic matter on the cassava field as a source of soil organic carbon. The study was aimed to evaluate the growth of some legume cover crops under cassava and their effects on soil properties. Methods: During September 2017-July 2018 legume cover crops (Calopogonium mucunoides, Centrosema pubescens, Pueraria javanica and the mixed) were planted under cassava variety of Mangu and UJ-5. The land coverage by the legume cover crops was measured monthly from 2 to 10 months after planting. Cassava growth was observed weekly from 8 to 32 weeks after planting. Soil properties were analyzed before planting and at harvesting of cassava. Result: Pueraria javanica was tolerant toward cassava shading. The land coverage was linearly increased along with the growth of cassava. At the end of cassava growth, the land area coverage by this legume cover crop was 98.08%. It produced more organic matter and could maintain soil moisture content than other legume cover crops. P. javanica could consider being a suitable legume cover crop under cassava to improve soil quality.

Soils under Shorea robusta in foot hills of the Eastern Himalaya - their characteristics and carbon sequestration potential

2020 ◽  
Vol 43 (4) ◽  
pp. 295-301
Author(s):  
Samar Gangopadhyay ◽  
◽  
Samar Banerjee ◽  
Avinash Jain ◽  
Saikat Banerjee ◽  
...  
Keyword(s):  
Organic Matter ◽  
Carbon Sequestration ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Bulk Density ◽  
Clay Content ◽  
Carbon Sequestration Potential ◽  
Shorea Robusta ◽  
Sequestration Potential ◽  
Study Sites

Forest soils supporting Sal-Shorea robusta (Roxb. ex Gaertn. f.) plantations in the foot hills of Darjeeling and Kurseong Divisions in West Bengal were studied for their physicochemical characteristics and carbon sequestration potential. Soils are acidic, high in organic carbon and clay content but low in soil reaction (pH) and bulk density (BD). Thick deposit of leaf litter and its decomposition products increase the soil organic carbon (SOC). Significant amount of clay content also increases the moisture content which helps in decomposing the organic matter, reducing the bulk density of soil and reduces erosion. Soil organic matter tends to concentrate with roughly more than half of the soil organic carbon in the upper soil horizons (0-30cm) at all the study sites. Among the study sites, Samardanga block registers lowest SOC while Bamanpukuri block shows highest SOC stock.

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