Growth of leguminous plants used as green manure under different salt levels in irrigation water/Crescimento de leguminosas utilizadas na adubacao verde em diferentes niveis de sais na agua de irrigacao

This study had the objective to evaluate the influence of salinity on the growth of legumenous species commonly used as green manure. An experiment was conducted in a greenhouse in the year of 2010 set up in 5 x 2 factorial in randomized blocks. Treatments were composed of five levels of salt (0.8, 1.6, 2, 4, 3.2 and 4.0 dS [m.sup.-1] at 25°C) in irrigation water and two legumenous species: Crotalaria juncea and Crotalaria spectabilis. Sodium chloride was added in the irrigation water and plants were irrigated manually on alternate days, based on water consumption of the previous day. The morpho-physiological parameters--plant height, stem diameter and number of leaves, were evaluated. Absolute growth rates and relative growth rates were adjusted to the regression models. Plants of Crotalaria juncea were not affected with salt levels used in this study. Depressive effect of salt levels was observed at 40 days for plant height, stem diameter and number of leaves of Crotalaria spectabilis, with linear response for plant height and quadratic for stem diameter and number of leaves.