Salt accumulation in the soil under a subsurface drip irrigation system

Salt accumulation in the soil profile is a challenge for irrigated agriculture and the study of salt concentration and its variation in the soil profile under different irrigation systems and management is needed. In this study, Sodium, magnesium, calcium and SAR concentration were studied under three irrigation regimes; farmer management (I1), Irrigation requirement (I2) and I2 plus leaching requirement (I3) in Safaeyeh in Kerman during two cultivation years (1391-1392). According to the results sodium, magnesium, and SAR deceased after irrigation but calcium did not affect by irrigation time. In development growth period, the highest values of SAR, sodium and magnesium were found to be corresponded to 75, 50 and 75 cm soil depth, respectively. The highest values of sodium and magnesium in I3 treatment were 123.4 and 43.6 meq/lit which were corresponded to the soil depth of 75cm. The highest value of calcium in I3 treatment was correspond to the soil depth of 25cm which was 52meq/lit. The highest value of SAR (12.4) was belong to the soil depth of 75 cm which indicates calcium has moved upward and toward the emitter. The interaction effect of irrigation regimes, soil depth, and recording time (before and after irrigation) showed that the highest concentrations of sodium, magnesium and SAR were 131.8, 74.4 and 54.3 meq/lit respectively, which were belong to I3 and 75 cm soil depth before irrigation. The highest amount of SAR was 12.8 which were belonging to I3 treatment, too. Calcium variations in the soil under I2 and I3 irrigation regimes shows the important of irrigation management for salinity control. The results showed that I2 have better performance than the other irrigation regimes due to less salt accumulation and SAR values in the root zone.