RESPONSE OF CHICKPEA TO NITROGEN SOURCES UNDER SALINITY STRESS

A hypothesis that nitrogen (N) nutrition moderates the sensitivity of plants to salinity (S) was tested in a greenhouse experiment by exposing the chickpea (Cicer arietinum L.) plants to four salinity levels (control, 2.5, 5.0 and 7.5 dS m(-1)) and three forms of N, i.e., nitrate (NO3), ammonium (NH4), ammonium nitrate (NH4NO3), and a control. The pot experiment was laid out in a completely randomized design (CRD) using three replications. The interaction between S x N demonstrated that salinity had significantly reduced plant growth, root length, water use efficiency, branches plant(-1), grain yield plant(-1) by increasing the root: shoot ratio irrespective of N form as compared to the control. Reduction in general, due to the form of N, was less in plants fed with NH4NO3 as compared with sole sources of N or control. Combined application of N had less reduction of absolute growth rate, water use efficiency, grain yield plant(-1) at higher salinity level. The difference amongst N forms on the braches plant(-1) was negligible, while root: shoot ratio was less affected in plots treated with NH4 form of N. These results suggested that combined use of N forms can minimize the reduction in plant growth probably by better control over the excessive accumulation of sodium, calcium, potash, sulfate, and chloride, which normally occur with applications of N as solely NO3 or NH4.