Modification of the Mehlich Lime Buffer Test

Hoskins, Bruce R.; Erich, M. Susan

doi:10.1080/00103620802289372

Cited by 25 publications

(44 citation statements)

References 9 publications

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“…As stated by van Lierop (1990), it is well suited to predicting the LR to reach a target pH just above 5.5, which is sufficient to eliminate possible Al toxicity. The Mehlich buffer (0.411 meq acidity/unit of pH depression of 10 mL of buffer pH) is stronger than the SMP buffer (0.161 meq acidity/unit of pH depression of 10 mL of buffer pH) and hence requires a narrower soil/solution ratio (1:1:1 5 soil/water/buffer) and yields more stable buffer pH readings (Hoskins 2005). The hazardous chemical in this reagent is barium chloride dihydrate (82 mM), which displaces exchangeable acidity and also acts as a fungicide in the solution (North Carolina Department of Agriculture 2007).…”

Section: Evaluation Of Four Buffer Solutionsmentioning

confidence: 99%

“…The buffer exhibited nearly the same buffering capacity as the Mehlich buffer (0.414 meq acidity/pH depression of 10 mL of buffer pH) and did not show statistically significant differences from the SMP LR rates. The only considerable disadvantage of the modified Mehlich buffer is that it cannot be stored for more than 3 weeks (Wolf, Beegle, and Hoskins 2005;Hoskins 2005). This relatively short shelf-life is a result of barium removal from the solution, and it has the potential for fungal growth because the buffer is an excellent medium for microbial growth [i.e., it contains high concentrations of ammonia nitrogen (N) and carbon (C)].…”

Section: Evaluation Of Four Buffer Solutionsmentioning

confidence: 99%

“…The modified Mehlich buffer was developed by Hoskins (2005) primarily to overcome the drawbacks of the SMP buffer procedure (i.e., unstable buffer pH readings, rapid electrode degradation, poor precision of results, and the production of hazardous waste in the laboratory). Barium chloride dihydrate in the Mehlich buffer was replaced with calcium chloride dehydrate, a divalent cation, at the same concentration (82 mM).…”

Section: Evaluation Of Four Buffer Solutionsmentioning

confidence: 99%

“…Most of the buffers used to estimate LR contain hazardous components, including hexavalent chromium and barium, and there is a general trend toward developing buffers without these hazardous constituents (Hoskins 2005;Sikora 2006) or alternative methods of LR determination (Liu et al 2005). The Sikora and modified Mehlich buffers were designed to mimic the SMP and Mehlich buffers, respectively, but without the hazardous constituents.…”

Section: Introductionmentioning

confidence: 99%

“…The buffers originally proposed [Shoemaker, McLean, and Pratt (SMP) in 1961, Adams-Evans in 1962, Woodruff in 1948, and Mehlich in 1976 related the pH of a soil that was allowed to react with a buffer to the LR of a population of soils. The LR was determined by CaCO 3 incubation for a period of months (Hoskins 2005;McLean 1982). A calibration study of buffers is usually done to verify the accuracy of the test (Sims 1996) and the suitability of the buffer to the range of soil characteristics pertaining to a certain geographical region.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of Four Buffer Solutions for Determining the Lime Requirement for Ohio Soils

Viswakumar¹,

Mullen²,

Diedrick³

et al. 2010

Communications in Soil Science and Plant Analysis

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Lime is used as a soil amendment to achieve the optimum pH suitable for good crop growth. Buffer pH (BpH) measurements have been calibrated to relate the linear drop in pH of the soil-buffer system to the amount of lime needed to neutralize soil to a certain pH level. The amount of lime required to neutralize soil acidity, called the lime requirement (LR), is obtained from soil-limestone (CaCO 3 ) incubations. In this study, 13 soils from Ohio were incubated with CaCO 3 for a period of 1 month to determine the LR to achieve different target pHs. This LR was then regressed with the different BpHs of four buffer solutions [(1) Shoemaker, McLean, and Pratt (SMP), (2) Sikora, (3) Mehlich, and (4) modified Mehlich] to obtain calibration equations. The Sikora and modified Mehlich buffers are variations of the SMP and Mehlich buffers, respectively, but they are designed to promote buffering without use of any hazardous constituents [i.e., chromium(VI) in SMP buffer and barium in the Mehlich buffer]. This study was done to verify the applicability of the buffers that do not contain any hazardous constituents and to calibrate these buffers for predicting lime requirement needs for Ohio soils. Comparing the calibrated equations of the SMP and Sikora buffers with CaCO 3 -incubation LR recommendations revealed that the SMP and Sikora buffer solutions were not significantly different, and a single calibrated equation can be used for these two buffers to determine LR predictions in Ohio. The Mehlich and modified Mehlich calibration equations differed significantly from the SMP calibration equations and were not as highly correlated with CaCO 3 -incubation LR recommendations using a linear model (r 2 , 0.54). Thus, it is possible to use the Mehlich and modified Mehlich for determining lime recommendations, but they require a correction factor such as inclusion of the initial soil pH to improve the precision of the LR prediction. We also found the various buffers tested in this study were better able to predict LR rates for greater LR soils than low LR soils. In conclusion, successful laboratory tests to predict LR for Ohio soils are possible using alternative buffers that do not contain hazardous constituents.

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Section: Evaluation Of Four Buffer Solutionsmentioning

confidence: 99%

Section: Evaluation Of Four Buffer Solutionsmentioning

confidence: 99%

Section: Evaluation Of Four Buffer Solutionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Evaluation of Four Buffer Solutions for Determining the Lime Requirement for Ohio Soils

Viswakumar¹,

Mullen²,

Diedrick³

et al. 2010

Communications in Soil Science and Plant Analysis

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Lime requirement for agricultural soils: A review of the current and potential methods for routine use

Nguyen

2022

J. Plant Nutr. Soil Sci.

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Liming is one of the key agronomic practices to improve crop yields in acid soils because, among other things, it reduces aluminum toxicity and creates favorable conditions for crop growth. For an effective liming program, the methods to determine lime requirement should be as precise as possible. This paper reviews the existing lime requirement methods and discusses the potential of a new one suitable for routine use in the laboratory to test most agricultural soils. The most widely used lime requirement methods can be categorized into four groups: titration, incubation, buffer, and field methods. Other methods such as spectroscopy method or the use of empirical equations have also been adopted. Although some methods are highly reliable, they are not optimal for routine use because they are inconvenient during the laboratory procedures or cannot be validated for all conditions. Based on the linearity between soil pH and the added base in the pH range from 4.5–6.5 in most agricultural soils, a titration‐based method on 1:1 soil:0.01 M CaCl2 slurry of a single sample appears to be a promising candidate for routine use. In further studies, this generally applicable method should be evaluated to provide a better comparison to established methods for lime requirement determination.

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A comparison of soil liming requirement methodologies in temperate, Northern European pedo‐climates

Boyko

Paton

Walker

et al. 2023

J. Plant Nutr. Soil Sci.

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BackgroundLiming agricultural land is essential to optimise crop yield and soil nutrients. Despite the importance of pH management in agricultural soils, liming applications have been decreasing in the United Kingdom for decades. There is no comparison of contemporary and historical liming requirement (LR) methods for Northern European, temperate climate mineral soils high in organic matter (OM).AimsThe aims of this research were to thoroughly comparatively analyse current methodologies and to ascertain which soil characteristics contribute to LR reactions.MethodsAnalysis compared methods for determining liming values common in the United Kingdom (Scottish Agricultural College [SAC] look‐up chart, RothLime model), Europe and the United States (Shoemaker–McLean–Pratt, Sikora, Modified Mehlich buffers), and the 30‐min calcium hydroxide titration developed by the University of Georgia.ResultsRothLime and SAC highly underestimated the LR value in acidic soils. The buffers highly over or underestimated LRs. The UGA titration method is a cheap, easy and accurate method which could be utilised for high OM soils but requires further calculation development. The characteristics most associated with soil–lime reactions in this experiment were measures of exchangeability (cation exchange capacity and loss on ignition, and by proxy, lime buffering capacity).ConclusionsThere is an opportunity to create buffer calculators and titration equations adapted to high OM soils. These are suggested for further development, through a larger diversity of UK soil types grouped by buffering capacity ranges. Including soil exchangeability factors in lime management calculations may contribute to more accurate values and therefore better resource management. Increasing LR accuracy for site‐specific soil pH management, used in precision agriculture technologies, is a necessary tool for the conservation of natural resources like limestone, managing resource use efficiency, and for optimising yields.

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Modification of the Mehlich Lime Buffer Test

Cited by 25 publications

References 9 publications

Evaluation of Four Buffer Solutions for Determining the Lime Requirement for Ohio Soils

Evaluation of Four Buffer Solutions for Determining the Lime Requirement for Ohio Soils

Lime requirement for agricultural soils: A review of the current and potential methods for routine use

A comparison of soil liming requirement methodologies in temperate, Northern European pedo‐climates

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