Assessment of Soil Salinity and Waterlogging Effects on Sugarcane Chlorophyll Content and Relative Yield in the Ghataprabha Command Area, Karnataka, India
Description
Soil salinity and waterlogging pose significant threats to sugarcane (Saccharum officinarum L.) production in irrigated command areas of semi-arid regions worldwide. This study evaluates the impact of soil salinity on sugarcane actual yield, relative yield and chlorophyll meter (CM) readings in the Ghataprabha command area, Karnataka, India-a case study with broader implications for global irrigated agriculture. A total of 120 surface soil samples (0–30 cm) were collected during summer 2024 from salt-affected sites across Belagavi and Bagalkot districts, with GPS-recorded coordinates. Soil properties including electrical conductivity of saturated paste extract (ECe), pH, sodium adsorption ratio (SAR) and residual sodium carbonate (RSC) were analyzed. CM readings were assessed using a SPAD-502 meter on the third leaf from the top of sugarcane plants. Actual yields from non-saline reference plots averaged 85 t ha-1, declining to 36 t ha-1 under high salinity (>6 dS m-1). Relative yield was modeled using the Maas-Hoffman (1977) equation, identifying a salinity threshold (A) of 1.7 dS m-1 and a 13% yield decline per unit ECe increase (B). Results indicate a significant negative correlation (r = -0.82, p < 0.01) between ECe and CM readings, with values dropping from 45.2 at non-saline sites to 22.4 under high salinity (>6 dS m-1). Relative yields decreased to 42% at ECe = 8 dS m-1. CM readings showed strong linear relationships with both ECe (R² = 0.99) and relative yield (R² = 0.95), demonstrating the potential of chlorophyll meters as rapid, non-invasive tools for monitoring salinity-induced yield losses in salt-affected soils. Multivariate analysis revealed strong associations between sodicity indices (SAR, RSC) and both CM readings and yield parameters. These findings, consistent with global salinity challenges affecting 20% of irrigated lands, emphasize the need for salinity-tolerant varieties, improved drainage and CM-based monitoring to sustain sugarcane productivity in semi-arid agro-ecosystems worldwide.
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Institutions
- University of Agricultural Sciences Dharwad
- Karnataka State Remote Sensing Applications Centre
- New Mexico State University