| Sumario: | In order to conduct field improving works, a laboratory and greenhouse
study of soils of the N. W. of Neguev (Israel) was made.
The study of the original conditions, proved the presence of a loessic saline-alkaline
soil, with a high carbonate content. With these conclusions, improving treatments were
made to lessen the exchangeable sodium percentage (ESP) with a simultaneous leaching of
the soluble salts. The treatments included leaching with 5.000, 10.000, 15.000 and 20.000
Cu. m. of water per hectare.
Three subtreatments were made: without gypsum, with gypsum applied directly to
the soil and with gypsum added to water.
A salt sensible species, Phaseolus vulgaris (L.) was choosen, to verify the effects of
this improvement upon a crop. It was grown in a greenhouse under controlled temperature
and moisture conditions.
It has been concluded that the mere soil leaching is not enough to liberate the
quantity of Ca to replace the Na of the complex.
The addition of gypsum is useful, only, if it is accompanied by a leaching of more
than 10.000 Cu. m. per hectare. No differences between the gypsum applied directly to the
soil and that suspended in water, were noted. A complementary study using sulphur as a
chemical amendment is reccomended.
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