DYNAMICS OF MN AVAILABILITY OF AERATED SOILS BY ENVIRONMENTAL CONDITION

Abstract

Manganese is a micronutrient absorbed by the plant in the form of Mn2+, the available content of soils is between 1 and 10 mg.kg^-1, but it is the only element that undergoes major changes with climate changes (temperature, humidity, solar radiation) of tropical soils. The other nutrients do not change with climatic conditions. There is still no consensus on the mechanism of the dynamics of Mn solubilization in aerated soil. The known reactions are neutralization of Mn2+ toxicity by liming, forming Mn(OH)₂ and the other is increased solubilization by reducing MnO2 to Mn2+ by anaerobic microorganism.

This article presents the results of research on the dynamics of Mn2+, Mn-disp, availability of aerated soils. The soil temperature below 20 ^oC remains unchanged for a long time. But when the soil is heated and dried by solar radiation, a temperature > 50 ^oC, the Mn-disp increases from 5 to 70 mg.kg^-1. However, when the soil is moistened with rainwater, after a few days, the Mn-disp content returns to the initial value, 5mg.kg^-1.  Showing that, in order to remain stable Mn-disp content, it requires soil cover with vegetables, keeps it moist and keeps temperature fluctuations minimal to favor the development of microorganisms. 

The complementary research of the study of the dynamics of Mn-disp in soils, no reduction of MnO2 to Mn2+ or oxidation of Mn2+ to MnO2 was observed. That is, the increase or decrease in the availability of Mn does not alter the total levels of Mn2+ or MnO2 in the soils.

DOI:https://doi.org/10.56238/sevened2024.031-055