Aerogation: Crop root-zone aeration through subsurface drip irrigation system

Abstract

Subsurface drip irrigation as a source that provides the water directly to the root zone develops a saturated wetted front in the rhizosphere, particularly when the irrigation is close to 100% of evapotranspiration. Long duration irrigations collect root development around the drip emitters and relatively low hydraulic conductivity, mainly in heavy soils, lead to preservation of saturation in the root layer, resulting in lack of air, which is detrimental to the function of roots and directly influences crop development. The objective of this study is to examine whether the root zone aeration can improve the distribution of moisture in the soil thereby improving plant performance. For the investigation of this approach, a three-year experimental research was conducted, in a sugar beet crop, irrigated by a subsurface drip irrigation system. A technique for ventilating the root zone was developed, which comprises passing air in the irrigation water throughout the duration of irrigation using a venturi device and air supply under pressure after irrigation through a compressor. The air application (aerogation) affected the soil moisture in the root zone reducing the water content or repelled the water from the proximal environment of the emitter. Regarding the crop yield characteristics, the continuous air application gave a higher yield, although not statistically significant, than the conventional (without air) irrigation and aeration at the end of irrigation