Yield and N-use efficiency in rice-wheat system with different soil moisture regimes and fertilizer management

A field experiment was conducted during 2001–2003 at the Research Farm of Indian Agricultural Research Institute, New Delhi to determine the effect of moisture regime and various N sources [urea, urea plus farm yard manure FYM) and urea plus dicyandiamide (DCD), a nitrification inhibitor] on yield and N-use efficiency in rice-wheat system. At saturated soil moisture regime grain and straw yields of rice were 5.9 and 8.7 t ha⁻¹, respectively, while with intermittent wetting and drying, these yields were 4.4 and 5.9 t ha⁻¹, respectively. Urea plus FYM treatment recorded maximum grain yield of wheat. Agronomic efficiency (AE) of N in rice doubled in saturated moisture regime compared to intermittent wetting and drying with application of urea. When a part of N was provided through FYM, this increase was 25%. In wheat, however, there was no significant effect on the AE of N.