Survival of saplings of algarrobo blanco (Prosopis alba Griseb.) in saline and saline-sodic soils of the Rio Hondo Department, Santiago del Estero, Argentina

Abstract

The objective was to assess the rate of survival of young plants (during the first 3 years of life) of Prosopis alba (white carob) in different soil situations of the Rio Hondo Department, Santiago del Estero, Argentina. The trial was conducted under three conditions of soil: a) soils suitable for agriculture; b) saline soils without water table (electric conductivity 3.9 to 7 dS/m) and c) highly saline soils with saline-sodium water table (electric conductivity
17-22 dS/m). The white carob seedlings were planted in wells of 40 cm wide x 40 cm long x 60 cm deep, at the end of the rainy season (March-April). The distance was 5 m between rows and 3 m between plants, totaling a density of 660 saplings/ha. Plots of 50 x 9 m (4 for each of the 3 soil conditions specified in the objectives) were implanted, determining the survival rate of saplings by counting individuals with normal growth during the first 3 years of experiment. Data were analyzed with anlysis of variance for a complete randomized design
and evaluating significant differences by means of Tukey´s test (α < 0,05). The performance of the saplings was strongly influenced by the presence/absence of saline water table. In both soils suitable for agriculture and saline without water table, P. alba had adequate development and a very low initial loss of plants; in saline-sodic soil saturation profile contribution of water table and rainwater prevented/difficult draw, they appeared under hypoxia (oxygen deficiency) in the root zone and most of the plants were affected severely, surviving at the third year, only 2% of the implanted initial density (660 seedlings/ha). We conclude that saplings survival of P. alba in soil salinity/sodicity values above 17 dS/m is significantly reduced from the first year of life; in the edafic conditions in agricultural soils and saline soils without water table, no significant reduction of saplings was found during all
the study period.