ISSN: 1659-2751

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Analysis of the Use of Acidifying Minerals to Regulate Alkalinity Derived from Carbonates

Abstract

Soils with high pH present a problem for agricultural production since their physiochemical characteristics limit the availability of certain elements required by crops. The management of these soils has a high cost. The objective of this research was to evaluate the effectiveness of the application of acid soil and acidifying compounds to improve the pH and electrical conductivity (E.C.) of soils with high pH. The acid soils used were from EARTH University, Limón and high pH soils were obtained from Tempisque, Guanacaste. The study was conducted in laboratory and greenhouse. Two laboratory studies evaluated different acidifying compounds and combinations of these with acidic soil. The results indicated that by combining acid soil and humic acid, the pH was maintained in the range of 6.23 to 6.83 and E.C. between 3.51 mS/cm to 5.09 mS /cm. In the evaluation of individual compounds, H3PO4 was able to reduce the pH of alkaline soil, maintaining it in a range of 5.18 to 5.70 and the E.C. was between 7.48 mS/cm and 7.20 mS/cm. Two products were developed for evaluation in a greenhouse trial, where the best biomass yield was obtained with product two, a mixture of acid soil, sulfur, (NH4)2SO4, citric acid, and H3PO4 resulting in a dry matter weight of 3.90 g in 30 days. In the second phase, where different proportions of acid soil with and without fertilizers were applied, no statistically significant differences were found between treatments for plant biomass. However, the application of 10 % or 20 % of acid soil decreased the pH and EC of the alkaline soil; the values were in ranges of 5.80 to 7.08 and from 0.47 mS/cm to 3.98 mS/cm, respectively. It was determined in phase three that using acid soil without additives regulated pH and EC of alkaline soil. The application of acid soil reduced the pH of the alkaline soil from to 7.7 to 6.59 and EC from 10.98 mS/cm to 2.75 mS/cm. The application of acid soils to alkaline soils is a viable option for improving pH and E.C. and thus improving their production potential.

Key words: electrical conductivity, inorganic compounds, pH, alkaline soils, acid soils.

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