Effect of micro-irrigation methods on the salinity of the soil profile in a grape vineyard. I. Electrical conductivity of sodium, chloride and boron at several points of the profile.

Alfonso Osorio U.1 y Ricardo Césped R.

In a table grape vineyard, cultivar Thompson Seedless, located in the saline alluvial soils (Aridisoles Paleorthids), of the valley of Copiapó, Northern Chile, soil salinity and the content of sodium, chloride and boron were measured, using the saturation extract. The samples were obtained at different depths, using different spatial sections in relation to the drip line and plantation row, considering three irrigation treatments: a single lateral drip line, with emitters of 4 L h-1 spaced at 1 meter (witness); a double lateral drip line, with emitters of 2 L h-1, spaced at 1 meter; and a single lateral sprinkler line using microjets of 14 L h-1 per plant. The results indicate that soil salinity decreases close to the emitter or microjet and increases farther away from it. The maximum salinity is encountered at the mid-point between two drip lines (condition between lines) and in first 40 cm of the soil profile. In general the large majority of salinity values found in the soil are superior to 5 dS m-1, for the three treatments, surpassing the tolerance threshold for the cultivation of table grapes. The content of sodium, chloride and boron in the soil also are high in relation to the tolerance range for table grapes. Under the tested conditions, the single line and microjet sprinkler treatments present a better control of the salinity in the root zone.

Keywords: irrigation, soil salinity, grapes
1 Instituto de Investigaciones Agropecuarias, Centro Regional de Investigación Intihuasi, Casilla 36-B, La Serena, Chile. E-mail: aosorio@inia.cl.