Physico-Chemical Characterization of Kole Wetland Soils in Thrissur District, Kerala: Implications for Paddy Cultivation and Wetland Management

Kole wetlands of Thrissur District, Kerala, represent a unique low-lying rice-growing ecosystem of significant ecological and agricultural importance. This study investigated the physico-chemical properties of soils from nine representative sites across the Kole lands to assess their fertility status and redox characteristics. Soil samples were analyzed for moisture content, pH, electrical conductivity (EC), oxidation-reduction potential (ORP), total dissolved solids (TDS), salinity, specific gravity, and macronutrients (organic carbon, phosphorus, and potassium). Results revealed considerable spatial variability in soil properties. The pH ranged from 3.28 to 8.13, with most sites exhibiting near-neutral to slightly alkaline conditions favorable for rice cultivation. ORP values ranged from 250 to 393 mV, indicating predominantly oxidized conditions in the surface soils. EC values (0.00268–0.00730 dS/cm) and salinity (0.01–0.03%) were low, confirming the freshwater nature of these wetlands. Organic carbon content varied from 0.68 to 1.02%, while available phosphorus (16–17 kg/ha) and potassium (187–198 kg/ha) were within acceptable ranges for rice cultivation. One site (Pullazhi Wetland) exhibited anomalous characteristics with extremely low pH (3.28), high ORP (393 mV), and elevated EC (0.00730 dS/cm), suggesting localized acidification or contamination. The findings provide baseline data for sustainable management of Kole wetlands and highlight the need for site-specific soil betterment strategies to maintain soil health and agricultural productivity in this ecologically sensitive region.