Amelioration of saline-sodic soils of Lower Seyhan Plain with different methods

This study was carried out to investigate the effects of different gypsum amounts, different application methods of gypsum and different leaching irrigation methods on the EC, pH, SAR, NaX and ESP of the saline-sodic soils using large and small soil columns.Attributes of treatment soil are saline-sodic (ECe=4.54-9.67 dS.m-1 ESP=49.1-62.0) and leaching waters ranged between saltless and medium saline (ECw=0.70-6.28 dS.m-1). Saline waters were used to leachate the soil in the beginning of experiment to increase the hydraulic conductivity of the soil and diluted to towards saltless water. The study involved gypsum application rates of 13 and 20 kg per m2, respectively for both large and also small soil columns. Gypsum was mixed to the first 5 cm and 10 cm of top soil on disturbed small and large soil columns, respectively. Also, gypsum was mixed to the first 5 cm of top soil and installed whole soil using vertical mulch technique for monolith soil columns. Drip and intermittent ponding irrigation methods were used to leachate to the soil columns. According to results: the treatment with 20 kg per m2 gypsum was mixed into whole soil profile and used intermittent ponding technique was found to be the most effective combination as statistical 0.95 importance level to decrease ESP in the large soil columns. Whichever gypsum amount is chosen, gypsum must be mixed on the top of soil with intermittent ponding; if gypsum amounts are be increased then gypsum must be mixed whole soil for monolith soil columns to decrease ESP (0.01 importance level). To decrease ESP on the disturbed small soil columns, 20 kg per m2 gypsum must be applied with drip irrigation.