CHARACTERIZATION OF BLACK SOILS UNDER RAMTHAL MICRO IRRIGATION PROJECT FOR SALINITY PARAMETERS
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Date
2018-06
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University of Horticultural Sciences, Bagalkot
Abstract
Topography is one of the important soil forming factor having great influence
on the movement of water and salts along with it. Considering its importance, an
extensive soil survey was carried out to assess the soil salinity parameters and
distribution of cations and anions along the gradient in a block of Ramthal Micro
Irrigation Project, Hungund, representing typical black soils. Representative profile
samples at different elevations were also studied. The samples were grouped into
three categories namely, high elevation (L1 : >526 m), mid elevation (L2 : 516-526 m)
and low elevation (L3: <516 m) areas.
The soil pH ranged from moderate to high alkalinity and it varied significantly
with elevations in the order of high > mid >low elevations. The electrical conductivity
ranged from 0.10 to 0.36 dSm-1. The soils at higher elevation (L1) recorded
significantly higher EC values compared to mid (L2) and low (L3) elevations. In terms
of cations, the soils existing at mid elevation (L2) recorded significantly higher
amounts of calcium and magnesium compared to soils of high elevation areas.
Contrastingly, potassium contents was found high in low elevation (L3) areas.
However, the sodium was found significantly high in higher elevations (L1). The
concentration of cations varied in the order of Na+> Ca2+> Mg2+> K+.
The total carbonates and bicarbonates was significantly lower in low
elevation areas (L3) compared to high and mid elevations (L1 and L2) areas.
Contrastingly, the chloride was maximum in high elevation (L1) areas compared to
mid and low elevations (L2 and L3). However, the sulphate was found significantly
higher in high elevation areas. In general the concentration of anions varied in the
order of Cl-> SO4
2-> CO3
2- + HCO3
-.
The soil profiles at three elevations also showed similar trends with respective
above salinity parameters. Interestingly, all cations and anions increased with depth.
However, the magnitude of increase was less in profile-3 representing lower elevation
(L3). The order of distribution of cations and anions among soil profiles at all soil
depths remained almost same. It was interesting to note that majority of the soil
samples were found susceptible for sodification with higher SAR and RSC values
though EC values are low. The study also indicated that the soils in the study area
were found suitable for most of the horticultural crops as there was no of salinity or
toxicity of cation/ anion.