Abstract:
The investigation was carried out to assess the total and available
micronutrients in soils of selected major land resource areas (MLRAs) of' Kerala.
The micronutrients investigated in the present study were iron, manganese, zinc,
copper and boron. The study was intended to establish the pattern of the distribution
of micronutrients both vertically and spatially in eight MLRAs viz, Palode,
Vellayani, Trivandrum, Mannar, Kottarakkara, Thakazhy, Ramankary and D-Block
soil series of Kerala.
Three extractables viz DTPA, EDTA and ammonium acetate were used
in the analysis. The available boron content in these soils was also determined by
hot water extraction method. All the micronutrients showed great variation in
their distribution in the various horizons of the profiles. The micronutrients content
of the soils estimated were correlated with soil properties like pH, organic carbon,
CEC and clay content. They were found to be positively and significantly correlated
with organic carbon, CEC and clay content while it was significantly and negatively
correlated with pH. The significant correlations revealed that the micronutrient
availability in these soils were influenced greatly by the soil properties mentioned
above.
From the results obtained, it was observed that micronutrients like iron
and manganese were well supplied in all the profiles studied. The micronutrients
were found to decrease with depth except in Ramankary, D-Blockand Thakazhy
series where it showed an irregular trend with depth due to the peculiar hydrologic
and oxidation-reduction conditions existing in these soil series.
The available and total micronutrients content in the surface soils from
places around the profile sites did not show any significant variation among places.
In almost all the samples very high iron content was recorded.
