Evaluations of Bentonite Plated Sulfur Application on Fe and Zn Bioavailability of Saline and Sodic Soil

In saline and sodic soils, high pH strongly have affected on soil micronutrient availability. The study was conducted to evaluate using soil amendments (sulfur and manure) on some soil characteristics, iron and zinc concentrations of saline and sodic soil. A factorial randomized complete blocks design was considered with three replications. The main factor included organic matter (manure) as two levels (M0 = without manure and M1 = 40 tons manure/ha) and subfactors were bentonite plated sulfur and Thiobacillus thiooxidans (five treatments) includes S0 = control without S, S1 = sulfur applying as soil gypsum requirement (1620 kg/ha), S2 = sulfur applying as double soil gypsum requirement (3240 kg/ha), S1T= S1+ Thiobacillus thiooxidans treatment, S2T = S2+ Thiobacillus thiooxidans. The irrigation treatments were performed based on soil moisture monitoring plots. Also, the soil samples were taken in depth 0-30 cm and analyzed for determing soil pH, electrical conductivity (EC), sodium adsorption ratio (SAR), soil Fe and Zn DTPA (diethylene triamine pentaacetic acid) -extractable concentrations. The results showed that the manure and sulfur treatments were significant difference on soil EC, SAR and Zn DTPA-extractable. Also, the compare mean Duncan's treatments revealed that Zn DTPA-extractable concentrations was increased from 1.7 (M0S0) to 4.1 (M1S2) mg/kg (p<0.05). Fe DTPA-extractable concentrations had increasing trend from 5.3 (M0S0) to 8.2 (M0S1T) mg/kg but the differences had not significant statistics (p<0.05). The interactive effects of sulfur and organic matter application reduced soil SAR from 15.5 in the M0S0) treatment to 9.9 in the M0S2T treatment (in which sulfur was used together with Thiobacillus thiooxidans. Finally, organic manure and sulfur were recommended for increasing efficiency saline and sodic soils.