Abstract

DIAZ-POVEDA, Vanessa Catalina  and  SADEGHIAN, Siavosh. Evaluation of a rapid method to determine lime requirements in acid soils of the Colombian coffee zone. Rev. acad. colomb. cienc. exact. fis. nat. [online]. 2021, vol.45, n.177, pp.1246-1261.  Epub Feb 21, 2022. ISSN 0370-3908.  https://doi.org/10.18257/raccefyn.1405.

Determining the lime requirements (LR) for acidic soils requires practical, fast, and effective methods. Some of the options currently used underestimate these requirements while others lead to overestimations. Here we evaluated the direct titration methodology with calcium hydroxide (Ca(OH)2) as a faster alternative to the incubation method, which was used as a standard. We used 25 samples from the Colombian coffee zone with pH<5.5 and contrasting physicochemical properties. We treated them with increasing doses of dolomite (CaCO3.MgCO3) in the incubation method and with Ca(OH)2 0.02 M in the titration method. The increase in pH in response to the treatments in the incubation method was exponential and less than that obtained with the titration method. In all soils, the titration method showed a linear trend and underestimated the lime requirements to reach a pH=5.5 compared to the incubation method. A multiple regression analysis (R2=0.94**) was used to explain the differences in lime requirements between the two methods based on several properties of the soils and generate the correction factor that should be added to the dose determined by the titration method. The soil properties considered in the regression analysis were the organic matter, N, P, K, Mg, S, Al, Na, Mn, Cu, B, and silt contents. We concluded that although the titration method with Ca(OH)2 is faster than the incubation method to determine the LR, its application in the Colombian coffee zone requires an adjustment factor based on the properties of the soil.

Keywords : Soil acidity; Liming; Incubation; pH; Titration-Ca(OH)₂.

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