HomeInternational Rice Research Notesvol. 25 no. 2 (2000)

Comparing management techniques to optimize fertilizer N application in rice in the Cauvery Delta of Tamil Nadu, India

P. Stalin | T. M. Thiyagarajan | S. P. Ramanathan | M Subramanian

Discipline: Agriculture



With the present levels of fertilizer N use efficiency (NUE) (<40%) in rice, it is estimated that an increase of about 300% in N use will be required to achieve an average yield of 8 t haÐ1 by 2025 (Cassman and Pingali 1995). Many fertilizer application methods and fertilizer types can help optimize N use in rice. In this paper, the following techniques and fertilizer types were evaluated on an Udorthentic Chromustert soil at TNRRI in the Cauvery Delta, during the 1997 and 1998 dry seasons (DS): the model Manage-N to optimize dose and timing of N application (Thiyagarajan et al 1994), the chlorophyll or SPAD meter to dose topdressing of N (Peng et al 1996, Balasubramanian et al 1999), controlled release fertilizers (Shoji and Gandeza 1992), and a soil test crop response-based N application (STCR-N) developed in India.