Assessing Reliability of Recycled Water in Wicking Beds for Sustainable Urban Agriculture

Abstract

Urban agriculture requires sustainable solutions to secure its water resources. A wicking bed (WB) is a simple system that could provide high yield and water use efficiency. This single trial glasshouse study compares the performance of a WB and surface irrigation (SI) system for growing tomatoes (Solanum lycopersicum L.) using fresh (FW) and recycled water (RW). The performance of both treatments was compared when irrigating 2 days per week and for two environmental conditions (indoor and outdoor). In addition, the reliability of using FW and RW at a 7-day irrigation interval was studied for WBs alone. Results showed that the irrigation water use efficiency (kg/m3) and the yield (kg/plant) are significantly different only between WB (FW) and SI (RW) considering all conditions. The accumulation of salts and the sodium absorption ratio (SAR) were high in the surface layer of WBs compared to SI. This indicates that the use of RW affects the level of salinity and sodicity in soil, which in turn may decrease the yield. However, WBs perform similar to, if not better than, SI with FW. The WBs show the advantage of reducing the leachate of nutrients into groundwater, compared to SI systems. Further research into irrigation and nutrient management in WBs to reduce the effect of salinity at the surface is recommended to increase the efficiency of the system.

Keywords

• irrigation
• salinity
• urban agriculture
• wicking bed
• water use efficiency
• yield