Improving the distribution uniformity of air flow rates from emitters in oxygenation systems

Subject Areas : Farm water management with the aim of improving irrigation management indicators

Manouchehr Torabi ¹ , David Midmore ² , Kerry Walsh ³ , Surya Bhattarai ⁴

1 - Academic member, Esfahan Agricultural and Natural Resources Research Center, P.O. Box: 81785-199
2 - Professor at Centre for Plant and Water Sciences, Central Queensland University, Australia; Professor at Central Queensland University, Australia; Research fellow and senior lecturer at Central Queensland University, Australia
3 - Professor at Central Queensland University, Australia; Research fellow and senior lecturer at Central Queensland University, Australia
4 - Professor at Central Queensland University, Australia; Research fellow and senior lecturer at Central Queensland University, Australia

Received: 2013-10-09 Accepted : 2015-02-02 Published : 2014-12-21

Keywords: air bubble, Christiansen uniformity coeffi, oxygenation, Surfactant,

Abstract :

Research carried out so far indicates that oxygenation is capable of effectively increasing crop yield because of supplying sufficient oxygen in the rhizosphere. However, the severe non-uniformity associated with the distribution of emitter air flow rates along laterals is a major deficiency. This research explored the effect of individual and/or concurrent use of surfactant with a final concentration of 32 ppm to irrigation water and/or insertion of turbulence-inducer sealing plugs preceding connectors on the uniformity of emitter air flow rate distribution. The results indicated that addition of surfactant raised the CUC of the emitter air flow rates from -83% to 37% for the asymmetric connectors and from 1% to 23% for the symmetric connectors, respectively, over the controls without surfactant. Addition of surfactant to oxygenation systems with symmetric connectors of 9.5 and 7 mm long led to a rise in CUC from 1% to 23%, and from -41% to 39%, respectively. Compared to aerated water without surfactant or sealing plugs, concurrent use of surfactant and turbulent-inducer sealing plugs in oxygenation systems with symmetric and asymmetric connectors caused a rise in the CUC of air bubble deliveries from -82% to 48%, and from 1% to 53%, respectively.