Evaluation of various fertilizer-nitrogen recommendations for rice in Cauvery Delta of Tamil Nadu

On-station and on-farm trials were carried out in Kuruvai season (dry season) during 1996–98 to generate and test verify various methods of N recommendation for rice-simulation tool MANAGE-N, soil test crop response N (STCR-N), chlorophyll meter based N and controlled release urea-N (CRN-urea). Application of N based on MANAGE-N (168 kg N ha⁻¹) recorded significantly higher grain yield in on-station trials. In the on-farm trials, MANAGE-N involving precise timing of N and CRN-urea (60% of the STCR-N) registered almost similar grain yields (6.30 and 6.37 t ha⁻¹, respectively). In the SPAD based N application, the grain yield was low, but greater N use efficiency could be realised with less N application.