Effect of different levels of sodicity on soil enzymes, soil microbial biomass carbon and activity of antioxidant enzymes in different rice varieties under semi-arid conditions

Soil sodicity is a major abiotic stress for crop production in many parts of the world. Soil enzymes have been proposed as potential indicators of soil quality due to their connection to soil biology, ease of measurement and quick responsiveness to changes in soil management. Concerning that how different levels of sodicity affects the activity of soil enzymes, soil MBC and antioxidant enzymes in different rice varieties will promote us to understand the mechanism behind the tolerant varieties and to find out the ways to improve the tolerance mechanism.

A field experiment was conducted at Anbil Dharmalingam Agricultural College and Research Institute, Tiruchirappalli, Tamil Nadu during September 2022 to January 2023. Different rice varieties viz., TRY 1, CO 43, TRY 2, CSR 27, TRY 3 and white ponni (WP) were grown at different levels of Exchangeable Sodium Percentage (ESP) i.e., 8, 16, 24, 32, 40 and 48 under field condition. The soil samples were collected at flowering stage and analyzed for urease, alkaline phosphatase (APH), dehydrogenase (DHG) and soil microbial biomass carbon (MBC). The plant samples collected at flowering stage were examined for activity of antioxidant enzymes like catalase (CAT) and peroxidase (POX).

The growth and yield decreases with increasing sodicity levels. The soil enzyme and microbial biomass carbon (MBC) found to be decreased with increasing ESP levels. The antioxidant enzyme increases with increase in sodicity levels in tolerant varieties and decreases at high ESP levels in susceptible varieties. Overall TRY 3 outperformed under increasing sodicity levels compared to other varieties.