Analysis of factors affecting the availability of air bubbles to subsurface drip irrigation emitters during oxygation

Factors of relevance for improving the uniformity of oxygen distribution in drip irrigation water*

“…Distribution of air (or oxygen) to the root zone of the crop in the form of microbubbles is a key to large-scale adoption of aerated irrigation. Torabi et al (2013) demonstrated effects of the connector type, water flow in the emitter, pipe diameter, and the layout of the pipeline all significantly altering the distribution of bubbles in irrigation water aeration. To intuitively grasp the flow state of oxygen in aerated irrigation, analyses were conducted to elucidate the air flow in two-phase flow in irrigation tape (Bhattarai et al, 2013).…”

“…The addition of surfactant has been shown to improve the uniformity of air bubble distribution in a two-phase flow of water and air (Torabi et al, 2013). Lei et al (2014) reconfirmed that water flow uniformity was greater than 95%, and the air flow uniformity remained above 70% with a surfactant concentration of 4 ppm.…”

“…Through the use of a bubble visualization unit, the total air void fraction in aerated irrigation water was estimated by Bhattarai et al (2013). Torabi et al (2013) used a cylinder full of water inverted into a sink and filled with irrigation water to collect the air over a set time period from the end of the drip tape. However, these methods only measure large bubbles (macro-/microbubbles and unseparated air lumps) and do not measure DO concentration along the drip tape.…”

Calculation of Uniform Coefficient, Soil Moisture Distribution and Analysis of Level of Biofilms Strategy under Sub Surface Drip Irrigation

“…Emitter clogging has become the major problem limiting more widespread use of drip irrigation, because it can reduce the service life and benefits of a drip irrigation system (Torabi et al, 2013). In the present research the level and characteristic of biofilms formed in the drip laterals were studied.…”

“…The actual evapotranspiration was estimated by multiplying reference evapotranspiration with crop coefficient (ET = ET 0 x K C ) for different months based on crop growth stages. The crop coefficient during the crop season 2013-14, 2014-15, was adopted as 0.50, 0.65, 1.15 and 0.75 at initial, developmental, middle and tuber maturity stages, respectively (Payero et al, 2008;Torabi et al, 2013). During the initial and developmental growth stages, until tuber formation, it is essential, that soil should be kept constantly and uniformly wet to a depth of at least 10.0-15.0 cm.…”