Swiss Chard (Beta vulgaris L.) Water Use Efficiency and Yield under Organic and Inorganic Mulch Application

South Africa is considered as a water scarce country and water shortage is a major constrains that often limits growth, yield, and quality of Swiss chard. A field experiment was conducted on Swiss chard (Beta vulgaris L.) in loamy soil to evaluate Water Use Efficiency (WUE), weed control, yield, and quality response to organic and inorganic mulch application during the winter/spring season (June to September). Treatments included bare-soil (control), grass/hay, and newspaper, white-maize-meal bag, white plastic and black plastic mulches. Black plastic, newspaper, and grass/hay mulches suppressed weeds significantly, which were encouraged under bare-soil, white plastic, and maize-meal bag mulch conditions. There was an increase in the number of leaves and leaf fresh mass with white plastic mulch, while bare-soil reduced plant dry mass and leaf area significantly. Leaf area was improved with white plastic, black plastic and maize-meal bag mulches. White plastic and grass/hay mulch improved WUE significantly, and exceled above other treatments at 259.9 and 242.0 kg ha-1 mm-1, respectively, followed by black plastic mulch at 207 kg ha-1 mm-1. Water use efficiency declined in the newspaper, maize-meal, and bare-soil treatments at 179, 130 and 74.7 kg ha-1 mm-1 WUE, respectively. Thus, the study reveals that the use of mulch under drip irrigation has an explicit role in increasing water productivity of Swiss chard.