Farmyard manure (FYM) and urea, alone or in different combinations all equivalent to 100 kg N/ha, were evaluated as nitrogen sources for lowland rice grown on a heavy alkaline vertisol. Their influence on soil chemical and electrochemical properties after submergence was also investigated. Soil solution analysis at various intervals after flooding revealed that water-soluble NH 4 +-N was reduced by increasing the proportion of nitrogen applied as FYM. The build-up of NH 4 +-N with FYM alone was only marginally different from that of the nil-N control. In general, pH, Eh, pCO 2, Fe 2+ and Mn 2+ were not affected by amending the soil with FYM alone or in combination with urea. The most noticeable effect of FYM was an increase in water-soluble phosphorus. During the four seasons of investigation in the field and one season in pots grain yield responses were reduced as the proportion of N from FYM increased. Grain yields from FYM only and nil-N did not differ significantly. FYM was a poor source of nitrogen for lowland rice.