Submitted to: Proceedings of the International Salinity Forum
Publication Type: Proceedings
Publication Acceptance Date: 4/11/2005
Publication Date: 4/25/2005
Citation: Suarez, C.L., Santana, J.L., Suarez, D.L. 2005. Effect of leaching on soil irrigated with sodium bicarbonate water applied by drip irrigation, with two irrigation and nitrate treatments. In: Proceedings of the International Salinity Forum, Managing Saline Soils and Water: Science Technology, and Soil Issues. April 25-27, 2005. Riverside, CA pp:159-162. Interpretive Summary: Irrigated agriculture is faced with decreasing amounts of high quality water hence the need to utilize lower quality water supplies. This study evaluated the changes in soil properties over three years related to application of low quality irrigation water (especially elevation bicarbonate and pH) at two leaching and two N application regimes. Over the time period of the experiment there was no significant soil EC difference between leaching treatments but there was accumulation of salts in the between - row areas. The adverse effects of high pH irrigation water did not result in increased SAR, soil pH or salinity after 3 years of drip irrigation. Longer term studies are needed to fully evaluate the impact of high pH waters on soil properties and plant response.
Technical Abstract: Increasing demands on high quality water supplies means that agriculture must evaluate use of lower quality waters for irrigation. Saline waters are often high in nitrate concentrations, and in some instances may contain elevated concentrations of bicarbonates and high pH. In this study we examined the changes in soil properties associated with irrigation with low quality water with two different water applications (leaching fractions of .28 and .38) and two different nitrate applications (350 and 700 kg/ha N). There was a high correlation between increased EC of the soil water extracts and increased exchangeable sodium percentage in the soil. Leaching at the end of the experiment increased salinity and ESP at 15 and 40 cm, likely due to flushing of salts accumulating in the dry between-row areas between the dripper lines. The increased EC in the between-row area was confirmation of a horizontal movement and accumulation of salts. There was little difference in salinity in the dripper region between the two water applications. Soil pH remained below 7.0 despite irrigation with pH 8.6-8.9 water for three years. The expected adverse impact of elevated soil pH and increased soil water SAR requires long-term studies.