Vol. 1, Issue 10, Part C (2015)

Abstract
Grey water from eight households was collected and delivered to the University to investigate its suitability for plant irrigation and growth. Semi-field growth trials were conducted at an experimental site situated on the University campus. Two trials were conducted (others are planned) and the soil was re cycled. In the first trial representative vegetables used were: aboveground crops (spinach, and green pepper) and below ground tubers (potatoes and madumbes). In the second trial, aboveground (spinach and green pepper) and belowground (beetroot and onions) were selected. In all, three experimental treatments were employed throughout: tap water, hydroponic nutrient solution and grey water. Results from the first trial, showed that nutrient irrigated vegetables gave a significantly greater increase in plant growth, compared with grey water, and tap water treatments. However, in the second trial irrigation with grey water yielded significantly greater yields and overall plant growth for peppers, spinach and onion than was achieved with the hydroponic nutrient solution. The reason for the improvement in soil fertility and yield is not immediately clear, nor is there yet evidence of potential deleterious effects of grey water on plant growth. Additional information may be forthcoming from the further three planting trials envisaged and allow, in particular, negative factors that may accompany repeated grey water reuse to be controlled or ameliorated through research and appropriate guidelines. It will further help improve overall water usage, and promote public acceptance of the concept.