SOIL AND RHIZOSPHERE BIOMARKER PANEL FOR ARECANUT (ARECA CATECHU L.): INTEGRATING DISEASE RISK, NUTRIENT CYCLING, AND RHIZOSPHERE HEALTH

Abstract

Arecanut (Areca catechu L.) is a high-value perennial plantation crop whose productivity depends strongly on the biological condition of the soil–root interface. Unlike annual crops, arecanut remains exposed to cumulative path ogen pressure, seasonal moisture fluctuations, nutrient depletion and continuous organic-matter inputs throughout its production cycle. Conventional diagnosis based largely on visible symptoms may therefore detect disease or nutritional stress only after substantial physiological damage has occurred. A soil and rhizosphere biomarker ap proach offers an opportunity to shift arecanut management from symptom-based intervention towards early, sys tem-level assessment. This paper proposes a crop-specific biomarker framework integrating five major dimen sions- i) pathogen pressure, ii) beneficial microbial activity, iii) nutrient cycling, iv) abiotic stress tolerance, and v) soil-carbon functioning. Among the disease-associated markers, Phytophthora sp. represent a major surveil lance target because of their association with root, crown, fruit and bud-rot syndromes, while Pratylen chus, Meloidogyne, Rhizoctonia, Pythium, Sclerotium , and Fusarium provide additional indicators of root and nursery health. Beneficial microbial markers including Trichoderma, Bacillus, Streptomyces, Azotobac ter and Paecilomyces lilacinus provide complementary information on biological suppression, nutrient mobiliza tion and nematode regulation. Functional markers such as T22, BS114, BS181, BS019, BS080, BS008, BS214, BS217, BS265, B43 and BS065 further extend the framework from organism detection to biological processes. The proposed panel provides a multidimensional view of arecanut soil health in which pathogen abundance, nu trient availability, microbial functions, moisture resilience and organic-matter turnover are interpreted together. Its future validation across contrasting soils, seasons and plantation management systems could support develop ment of an Arecanut Rhizosphere Health and Disease Risk Index (ARHDI) for precision nutrient, disease and soil-health management.