Impacts of graywater irrigation and soil conditioning with mulch on cotton growth and soil properties

Field experiments were conducted to evaluate the impacts of graywater irrigation with and without soil conditioning with mulching on cotton growth and soil properties in El Paso, Texas, USA. Treatments included in the study were: freshwater irrigation without soil conditioning (control, treatment T0), freshwater irrigation with soil conditioning (treatment T1), graywater irrigation without soil conditioning (treatment T2) and with soil conditioning (treatment T3) with four replications. The pH, sodium absorption ratio (SAR) and electrical conductivity (EC) values of the graywater used in the study were 8.19, 16.0 and 1.54 dS/cm respectively. Results showed that graywater irrigation did not have significant impacts on cotton growth and lint yield. Soil conditioning with mulch increased cotton yield significantly (p < 0.05) compared with non-mulching regardless of water types. Graywater irrigation increased soil pH values significantly in the surface depth (0–15 cm), however, it did not have significant effects at greater depths (>15 cm). Significantly higher salinity and sodicity were observed in the upper 30 cm depths in the graywater irrigated mulched soils, while no changes were detected at greater depths (30–45 and 45–60 cm).