The study had the objective to evaluate the effect of water salinity and the leaching fraction (LF) on soil salt accumulation and on the yield of grains of cowpea plants. A completely randomized block design, with four treatments and five repetitions, was adopted. The treatments studied were: 1 - well water with ECw of 0.8 dS m-1 (without LF); 2 - saline water with ECw of 5.0 dS m-1 (without LF); 3 - saline water with ECw of 5.0 dS m-1 with LF of 0.14, and 4 - saline water with ECw of 5.0 dS m-1 with LF of 0.28. The following parameters were evaluated: soil salt accumulation, vegetative plant growth, yield, gas exchange and leaf ion contents (Na+, Ca+2, K+, and Cl-). The saline water application provoked salt accumulation in the soil profile, but this effect was partially reverted by the increase of the leaching fraction. Salinity reduced plant yield, but it did not affect its quality. The reduction in plant yield was related, at least in part, to decrease in net assimilation of carbon during flowering and fruit development due to osmotic effects and to accumulation of potentially toxic ions (Na+ and Cl-). In general, the increase in leaching fraction did not reduce the effect of the salinity on plant development.
saline water; Vigna unguiculata L. Walp.; salt stress
