Effect of saline waters on drought affected cluster bean

The influences of saline water irrigation of different concentrations (0, 40, 80 and 120 me l-1) were compared in droughted and undroughted plants of cluster bean (cv. FS-277) at its critical pre-flowering stage. Observations recorded on plant water status, diffusive resistance, nodulation behaviour and on different metabolic parameters (free proline, reducing sugars, starch and activities of N2-ase and nitrate reductase) after one and seven days of saline water irrigation revealed that the adverse effects were far greater in droughted plants revived with saline water, as compared to those which suffered only salt stress. These resulted in significant declines in growth and yield in the former as compared to the latter case, at all salt concentrations. The seed yield obtained in undroughted plants even under 120 me l-1, significantly exceeded the level of droughted plants revived with non-saline tap water. Since drought and salt stresses appeared to have cumulative adverse effects, it is proposed that irrigation with saline water at the critical stage, in the beginning of a dry spell, may be more rewarding than irrigation with saline waters at a belated stage when the plants have already suffered water stress. Salinity build-up in soil under this condition was not high.