LONG-TERM VALIDATION OF A MEMBRANE-BASED SUBSURFACE IRRIGATION SYSTEM - DOI: 10.7127/rbai.v11n500777

Resumo

This experiment is part of a series of studies to select potential semi-permeable membranes to enable membrane-based sub-surface irrigation. Two commercially available membranes, NF and RO, and an under-development FO-TFC membrane were used in a glasshouse trial for a complete growth cycle of common bean (Phaseolus vulgaris cv. Jade) on potable water (0.3 dS/m). For each of the membrane experimental units, water was delivered to plants through specially designed cross-flow subsurface irrigation cells. During the germination phase, membrane performance was evaluated by total percentage of germination, germination rate and mean germination time. Plant height and number of leaves were taken throughout the experiment. Fresh and dry weight of leaves and stem, along with stem diameter were measured at the end of the experiment. Analysis of leaf gas exchange further indicates the ability of the membrane-based irrigation system to meet crop water demand based on the effects of irrigation treatments on stomatal conductance. For all treatments, plants were able to reach reproductive maturity, with the best yield result observed for the FO-TFC membrane. This novel approach contributes to efforts to improve precision of irrigation water delivery as plants drive water across the membrane according to their evapotranspiration demand in both quantity and time.