Polymer coated controlled release urea and SPAD meter based nitrogen management strategies for transplanted rice

摘要

Response of rice to nitrogen fertilisation in Indian soils is universal and rice consumes high amount of fertiliser N in the country. Efforts have been made to improve the use efficiency of nitrogen in rice by suitable management strategies involvingthe use of controlled / slow release N fertilisers (Velu and Ramanathan, 1994), split application of N (Thiyagarajan et al. 1994) optimised time and rate of N application. More recently, timing of N application through the use of SPAD (Soil Plant Analytical Division, Minolta, Japan) meter as well as Leaf colour chart (LCC) is being attempted successfully (Kumar et al. 1999, Thiyagarajan et al. 2000; Balasubramanian et al. 2000) to economise the fertiliser N.