Acidification rate of limed soil in a semiarid environment

1997 ◽  
Vol 77 (3) ◽  
pp. 415-420 ◽  
Author(s):  
D. Curtin ◽  
H. Ukrainetz

To evaluate the benefits of liming acid soils, a method is needed to predict the longevity of its effect on soil pH. We coupled a simple index of soil buffering with estimates of the proton budget to predict long-term pH changes in a limed soil (Dark Brown Chernozem) in Saskatchewan. Analysis of published data for Saskatchewan soils showed that acceptable estimates of soil buffering can be obtained from organic matter and clay content. Buffer capacities of organic matter and clay were estimated at 487 and 26 mmol(±) kg−1 (pH unit)−1, respectively. Soil pH, titratable acidity, and effective cation exchange capacity (CEC) were monitored for 18 yr after lime application [Ca(OH)2 at rates of 0, 4.5 and 6.7 t ha−1] to field plots in a wheat (Triticum aestivum L.)-fallow rotation. In limed plots, there was a tendency for pH, exchangeable Ca and effective CEC to decrease with time in the 0–7.5 cm layer and to increase in the 7.5–15 cm layer. This was attributed to mixing of the two layers during cultivation. In the 0–15 cm layer as a whole, there was no discernible change in acidity, Ca, or CEC during the monitoring period. Negligible re-acidification in limed soil was consistent with the estimated H+ budget. External acidification sources were negligible (no N fertilizer was applied). Acidification due to leaching of nitrate and export of cations in grain over 18 yr was estimated at 6–7 kmol(H+) ha−1. This amount of acidity would lower soil pH by less than 0.1 units [buffer capacity of the top 15 cm of soil was ≈70 kmol(±) ha−1 (pH unit)–1], an amount too small to be detectable against background variability. Key words: Buffer capacity, organic matter, proton budget, titratable acidity

1968 ◽  
Vol 71 (1) ◽  
pp. 95-104 ◽  
Author(s):  
O. Talibudeen ◽  
S. K. Dey

SummaryThirty-four soils from the Rothamsted Experiments were exhaustively cropped with ryegrass in the glasshouse. The concentration and yield of potassium in ryegrass tops and the potassium intensity in the soil were measured every 4 weeks, after harvesting the grass.The change in K-intensity of soils, rich in potassium, with exhaustion differed from that of ‘poor’ soils. This change was related to the rate of change of the cumulative K-yield. The rate of change of soil K-intensity demarcated periods of intense and limited exhaustion and partial recovery of the soil during cropping.The cumulative K-yield of ryegrass was very significantly related to the K-intensity of the uncropped soil; the ‘16-week’ yield was slightly better related than the ‘60-week’ yield. For Park Grass soils, the relationship was improved by allowing for variations in soil pH.The K-intensity of all soils, with or without manuring, decreased to nearly 10-3 (M)½ in (AR)0 units after 16 weeks cropping, although large differences in K-yield persisted until much later.K-buffer capacity per unit clay content of the soil, measured by a laboratory method, was inversely related to the K-intensity of the uncropped soil. The K-buffer capacities of soils rich in potassium, measured in laboratory and glasshouse experiments, were significantly related, but were unrelated for ‘poor’ soils. The K-buffer capacity (laboratory method) of Rothamsted soils with different manurial treatments was only very approximately related to the cumulative K-yield.Less K was taken up from all Rothamsted soils given nitrogen fertilizer in the field and their K intensities were also smaller than the corresponding soils without ‘N’. Field liming of acid soils decreased their K-intensity and increased their K-buffer capacity, presumably because more potassium was removed by the field crop.A rapid method is suggested for measuring potassium intensities of soils.


Soil Research ◽  
1992 ◽  
Vol 30 (2) ◽  
pp. 119 ◽  
Author(s):  
RL Aitken

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.


1977 ◽  
Vol 57 (3) ◽  
pp. 361-370 ◽  
Author(s):  
M. D. WEBBER ◽  
DIANE CORNEAU ◽  
P. B. HOYT ◽  
M. NYBORG

Several laboratory methods for estimating lime requirements of acid soils were compared using 24 soils from Alberta and northeastern British Columbia and 15 from elsewhere in Canada. The Peech, Schofield, Woodruff and SMP (Shoemaker et al. 1971) buffer methods were equally well correlated with lime requirements for raising soil pH to 5.5 or 6, which in turn were highly correlated with the amounts of soluble and exchangeable Al and organic matter in the soils. The SMP buffer method is recommended for use as the diagnostic index of lime requirement to achieve pH 5.5 or 6 because of its speed and simplicity. A refinement is suggested for Alberta and northeastern B.C. soils on the basis that lime need not be added to achieve pH 5.5 but should be added to reduce Al below the toxic level for sensitive crops. The lime requirements to reduce Al in those soils were highly correlated with the amounts of 0.02 M CaCl2-soluble Al they contained and it is recommended that the 0.02 M CaCl2-soluble AI be used as the diagnostic index of lime requirement. Lime requirements related to SMP (pH) and 0.02 M CaCl2-soluble Al are presented.


2017 ◽  
Vol 29 (2) ◽  
pp. 123-131
Author(s):  
Reshma Akter ◽  
Md Jamal Uddin ◽  
Md Faruque Hossain ◽  
Zakia Parveen

A study was carried out to evaluate the effects of brick manufacturing on phosphorus (P) and sulfur (S) concentrations in soil and plant collected from different distances of brick kilns in four AEZs of Bangladesh. Forty eight composite soil samples (0 - 15 cm depth) were collected from 48 points in 12 different sites at 0 m, 300 m, 800 m and 1500 m from brick kilns, where most (site 2, site 3, site 5, site 6, site 7, site 9 and site 10) of the brick kilns used coal for brick burning purposes. Plant samples (rice straw and different vegetables) were also collected from the respective fields except 0 m distances. Significantly (p ? 0.05) lower organic matter, cation exchange capacity, clay content and soil pH were found at 0 m distances compared to other distances. Highest concentration of total P in soil were recorded at 0 m distances and these concentrations decreased with increasing distances from the brick kilns in most of the sites; whereas available P is significantly lower at 0 m distances than that of other distances. Total and available concentration of S in soil followed the trend 0 m>300 m>800 m>1500 m. Maximum accumulation of P (69.15 mg kg-1) and S (0.14%) in plant was found at 800 m away from the brick kiln.Bangladesh J. Sci. Res. 29(2): 123-131, December-2016


Soil Research ◽  
1998 ◽  
Vol 36 (6) ◽  
pp. 951 ◽  
Author(s):  
A. Ruth ◽  
B. B. Johnson ◽  
T. J. Fowler

This study investigates the influence of terrain, including steepness and position in slope, on soil pH, extractable aluminium (Al), and organic carbon (OC) in the Axe Creek catchment, Victoria. Both soil pH and Al were determined by use of 1 : 5 soil : 0·01 M CaCl2 extracts, with Al measured colorimetrically using a modified pyrocatechol violet method. Although all soils were acidic, the Al concentration was highest on the hilltops (>10 mg/kg) and lowest at base-of-slope sites (<1 mg/kg). The concentration of Al was generally inversely related to soil pH. However, on average, a lower Al concentration was found in the top 10 cm than in the interval from 10 to 30 cm, even though the soil pH remained relatively constant throughout the top 30 cm. The lower Al concentration in the surface layer corresponded to a substantially higher level of OC near the surface, suggesting the formation of Al-organic matter complexes.


Soil Research ◽  
1990 ◽  
Vol 28 (2) ◽  
pp. 259 ◽  
Author(s):  
JO Skjemstad ◽  
HVA Bushby ◽  
RW Hansen

The levels of iron and aluminium extracted from 36 surface soils by pyrophosphate, oxalate and dithionite are compared with a number of other soil properties. Correlations suggest that aluminium released by these extraction procedures is largely associated with organic matter while only a small fraction of the iron released is in this form. Significant correlations between soil pH and the negative logarithms of both oxalate (r = 0.715) and pyrophosphate (r = 0.959) extractable iron in soils with >20% clay content indicate that pH is the most significant factor in determining the level of ferrihydrite and iron/organic matter complexes in surface soils. The significance of these relationships in terms of soil weathering processes is discussed. Further, the data suggest that pyrophosphate extractable iron is a useful indicator of the most active, mobile component of iron in surface soils.


Soil Research ◽  
2013 ◽  
Vol 51 (6) ◽  
pp. 494 ◽  
Author(s):  
Denis Curtin ◽  
Stephen Trolove

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.


1987 ◽  
Vol 19 (7) ◽  
pp. 1293-1296 ◽  
Author(s):  
M. E. Mattiazzo ◽  
N. A. da Glória

The effects of microbiological activity on soil acidity components in soils previously treated with vinasse are determined. These soil acidity components were interpreted through the measurement of pH, exchangeable aluminium and titratable acidity. The results showed that there was no rise in soil pH when microbiological activity was absent, through periodic application of methyl bromide. It was concluded that organic matter oxidation is responsible for the rise in soil pH and microbiological activity is responsible for this oxidation. Thus, microbiological activity is necessary to raise the soil pH.


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