Characterization of Calcium and Magnesium Status in Arecanut (Areca catechu L.) Growing Soils of Koppa, Sringeri and Thirthahalli Taluks of the Malnad Region

Abstract

A survey was taken up in the year 2022 in the arecanut gardens of three selected taluks of the Malnad region viz. Koppa, Sringeri and Thirthahalli. The soil samples were collected at surface (0-30 cm) and sub-surface (30-60 cm) depths in healthy and unhealthy arecanut gardens and were characterized for secondary nutrients like calcium and magnesium. The diverse geological characteristics, rainfall patterns, organic matter content and agricultural practices all collectively contribute to the observed variations in calcium and magnesium content among different fractions and soil depths in these taluks. Among the various calcium and magnesium forms (water-soluble, exchangeable and residual/non-exchangeable), water-soluble form (3.3%) consistently showed the lowest quantities in the soils. Exchangeable form (26.3%) was found to be lower than residual form (70.4%). Also, exchangeable (61.5%) and water-soluble (38.5%) fractions contribute to the soil available pool. All the four forms of calcium and magnesium were relatively lower in Thirthahalli soils in comparison to the soils of the other two taluks. This could be attributed to lower content of calcium and magnesium containing minerals in acid soils coupled with their high rate of solubilization, low amounts of 2:1 clays and excessive leaching losses of ions in acid soils.The research study provides valuable insights into the distribution and forms of calcium and magnesium in arecanut-growing soils of the Malnad region, which is an important area for arecanut cultivation in India. Understanding the status and fractionation of secondary nutrients such as calcium and magnesium is essential for improving soil fertility management and sustaining crop productivity. The study contributes region-specific soil nutrient information that can support better nutrient management strategies for farmers and agricultural researchers working in humid tropical soils.