RESPONSE OF SEED CORIANDER (CORIANDRUM SATIVUM L.) VAR. VARADEVI 1 TO NITROGEN AND PHOSPHORUS LEVELS: GROWTH, SEED YIELD, SEED QUALITY, NUTRIENT UPTAKE AND ECONOMICS IN THE NORTHERN DRY ZONE OF KARNATAKA

Abstract

Nitrogen and phosphorus are the main nutrients that limit the production of seed coriander, but location-specific information on their combined effect on seed yield and physiological seed quality is scarce for the Northern Dry Zone of Karnataka, India. A factorial randomized block design experiment with three replications was conducted during rabi 2024-25 and 2025-26 at the College of Horticulture, Bagalkot, to evaluate four levels of nitrogen (20, 30, 40 and 50 kg ha-1) and four levels of phosphorus (20, 30, 40 and 50 kg P2O5 ha-1) on coriander var. Varadevi 1. Pooled over the two seasons, growth, yield attributes, seed yield, seed quality, essential oil and oleoresin content and crop nutrient uptake increased significantly with each increment of nitrogen and phosphorus and the nitrogen × phosphorus interaction was significant for most characters. Flowering was delayed slightly (by less than three days). The combination of 50 kg N and 50 kg P2O5 ha-1 (N4P4) gave the highest seed yield (825.69 kg ha-1), which was 76.6 % higher than the lowest combination (467.44 kg ha-1) and 35.1 % higher than the recommended dose of 30:40 kg N:P2O5 ha-1 (611.26 kg ha-1). The treatment combination of N4P4 also produced the heaviest seeds (14.62 g per 1000 seeds), the highest seedling vigor indices (1694 and 1983) and oleoresin content (9.11 %) and the highest net returns (₹ 87,070 ha-1) and benefit:cost ratio (3.37:1). Available soil nitrogen and phosphorus after harvest declined as fertilizer levels increased, whereas crop uptake increased. The response had not leveled off at the highest level tested, so the optimum dose may lie above 50:50 kg ha-1.