Effect of green manuring and nitrogen on yield of and uptake of micronutrients by rice

A field experiment was conducted to study the effect of different green manures (fallow, dhaincha, sunhemp, moong) without and with different levels of fertilizer-N (0, 40, 80, 120 kg ha⁻¹) on yield (grain, husk, straw) and uptake of micronutrients (Zn, Cu, Mn, Fe) in submerged rice. The rice yield and uptake of nutrients increased significantly with increasing N levels. Moreover, application of N along with GM (green manuring) showed additive effect on these parameters. Under all GM treatments, the yield and uptake were always higher with 120 kg N ha⁻¹ than with the lower levels of N. The effect of different green manures (GM) on rice yields and nutrient uptake was in order: sunhemp > moong > dhaincha. The highest yield of grain (5.52 t ha⁻¹), husk (2.36 t ha⁻¹), straw (8.04 t ha⁻¹) and uptake of all micronutrients were obtained where 120 kg N ha⁻¹ was applied under sunhemp as GM. The effect of interaction of N fertilizer and green manure on yield of and uptake of micronutrients by rice was not significant.