Evolución de la salinidad en un suelo irrigado del sudoeste bonaerense

the objective of this study was to elucidate the effect of drip irrigation on the salinity and sodicity of the soil under a 50-year old olive plantation, located near the town of faro, district of coronel dorrego, province of buenos aires. the irrigation water has an electrical conductivity of 2.1 dsm-1 and a sodium adsorption ratio of 13.8 dsm-1. the irrigation system is composed of two lateral drip lines in each row of trees. nozzles with a nominal flow rate of 1 l h-1 were spaced at 0.7 m. soil samples were taken from a 50 by 1,000 m area. four samples were taken from the front, two in the middle and two at the end. in each sampling point, samples were taken from four horizons under a nozzle and between nozzles. salinity and sodicity were related to electrical conductivity (ec) and to the sodium adsorption ratio (sar), calculated from the saturation extract analysis of soil samples. after three irrigation seasons, the ec of the soil extracts increased to values close to the ec of the irrigation water and the soil sar increased ten-fold. according to these observations, the appearance of sodicity problems becomes highly probable if the sar of the irrigation water is not corrected. these observations lead to the following question: are the salt content of irrigation water and weather conditions compatible for maintaining a sustainable agriculture in southwestern buenos aires? in order to answer this question, further studies over a wider period of time are needed since most sampling sites do not exhibit temporal stability in relation with the average conditions of salinity and alkalinity.