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 EI Paso, Texas, USA. Treatments included in the study were: freshwater irrigation without soil conditioning (control, treatment T-0), freshwater irrigation with soil conditioning (treatment T-1), graywater irrigation without soil conditioning (treatment T-2) and with soil conditioning (treatment T-3) 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).