CHARACTERIZATION OF SOILS FOR CHEMICAL PROPERTIES AND HEAVY METAL DISTRIBUTION UNDER DIFFERENT CROPPING SYSTEMS IN BELGAVI DISTRICT OF KARNATAKA
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Date
2020
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University of Horticultural Sciences, Bagalkot. (College of Horticulture, Bagalkot).
Abstract
A soil survey was carried out for assessment of physic-chemical properties and
heavy metal distributions under different cropping systems in Belgavi district of
Karnataka. Further, remediation experiment was conducted to evaluate the efficacy of
ameliorants in order to reduce the bioavailability of Cd, Ni and Pb in spiked soils.
The surveyed soil samples categorized based on elevation intervals and cropping
systems found to have soil reaction ranged from slightly acidic to alkaline (5.5-8.4). At
higher elevations due to leaching effect the soil pH was observed to be slightly acidic in
contrast to lower elevations which were found to be remained from neutral to alkaline.
In case of organic carbon, most of the soil samples remained medium to high in status.
Available micronutrients such as DTPA-Fe and Mn were found to be high in status in
majority of soil samples. The available Cu and Zn status were found to be medium to
high. DTPA extractable heavy metals such as Cd, Ni and Pb were found to be below the
critical limit in all the soil samples. Correlation studies showed that the soil pH and
SOC major influence on heavy metal availability. Cd, Ni and Pb were negatively
correlated with soil pH. However, the influence of soil organic matter was positively
associated with heavy metals.
An incubation study was performed in heavy metals spiked soils with various
ameliorants in order to evaluate the bioavailability and efficacies of amendments in
immobilization of Cd, Ni and Pb fractions. A vulnerable soil spiked with 100 ppm of
each Cd, Ni and Pb was treated with ameliorants like lime, potassium di-hydrogen
phosphate (KH2PO4), biochar, zeolites, FYM, vermicompost, gypsum and pressmud.
Among the ameliorants, lime (1%) found to be most effective in reducing bio-active
form of Cd. Potassium di-hydrogen phosphate (KH2PO4) (1%) was highly effective in
decreasing labile Pb. For Ni, amendments such as lime, pressmud, vermicompost and
zeolites performed best to other ameliorants in reducing mobile pool of nickel.