Vol. 2, Issue 4 (2015)
Effect of powder and liquid laundry detergents on Swiss chard plants
Author(s): Sachin Madhavrao Kanawade
Abstract: Reuse of grey water (non-toilet household wastewater) for irrigation is a potential means of recovering water and nutrients which would otherwise be lost through discharge. Irrigation of food crops can improve food security in poor communities. Laundry grey water represents a substantial proportion of overall household grey water. It holds potential benefits for irrigation use in that it contains some plant nutrients, but also has potential problems because it contains salts which can be harmful to plants and soil. In this study, Swiss chard plants were irrigated for 96 days with laundry grey water generated with either powder or liquid laundry detergent. A balanced nutrient solution and tap water were used as comparative treatments. Plants irrigated with nutrient solution performed markedly better than all other treatments. Laundry grey water generated with powder detergent produced similar plant growth and yield as tap water. However, high electrical conductivity, sodium concentration and sodium adsorption ratio in the grey water indicated that soil problems were likely in the longer term. Plants irrigated with laundry grey water generated with liquid detergent fared the worst. Grey water analysis suggested that this could be attributed either to high chemical oxygen demand, resulting from higher detergent concentration in the liquid detergent than in the powder detergent, or to boron which was present in only the liquid detergent. Comparison of accumulation of biomass by roots and leaves in all treatments other than the nutrient solution treatment was suggestive of nutrient deficiencies. The pH of all irrigated soils increased slightly over the experimental period, but did not differ significantly among treatments.