Characteristics of Maize Roots under Subsurface Drip Irrigation through Various Oxygen Treatment

다국어 초록 (Multilingual Abstract)

In Korea, irrigation technology using subsurface drip irrigation (SDI) is new in agriculture system. Many limitationsof SDI are not well known. SDI can damage crops from overwatering. To address this weakness, it isimportant to improve and test the applicability of the SDI with air injection (oxygation). Therefore we investigatedsoil oxygen (O2) and carbon dioxide (CO2), root characteristics and yield of maize using two conditionsof soil moisture regime: field capacity (FC) × 100% and 120%. Maize was planted, and then air was injectedby compressor and venturi. In the field, irrigation was controlled by a controller connected to soil moisturesensors. Soil moisture sensors were measured at 20 cm below soil surface. Soil O2 and CO2 were measured at10 and 30 cm below soil surface before and after oxygation. Root activity was measured from tip of roots.
Root volume and dry weight were measured. Post-harvest, number and weight of maize ears were surveyed aswell. As a result, soil oxygen values increased by 59% in the compressor treatment and by 34% in the venturetreatment. However, soil CO2 values did not depend on the oxygation. In all soil moisture treatments, theactivity of oxygated roots was greater than that of the control, and root activity was increased by 152%. Rootvolume and dry weight were also greater than those in the control. No significant effect of soil moisture wasfound on the number and weight of ears of maize. The average ear weight of maize in the FC 100% soilmoisture treatment was 1,292 kg 10a-1 in the oxygation and 1,278 kg 10a-1 in the control. In addition, no effectof oxygation was observed on number and weight of ears. The average ear weight of maize in the FC 120%soil moisture treatment was 1,229 kg 10a-1 in the oxygation and 960 kg 10a-1 in the control. Maize yield was28% greater in the oxygation treatment than that in the control. The yield of maize grown in the control fieldshowed a tendency to decrease as the soil moisture content increased. At FC 120% soil moisture, the earweight of control maize was reduced by 25% compared to FC 100% soil moisture. These results reflected thatthe oxygation process had a great effect on the root growth even in humid conditions, which was expected tohave a positive effect on the maize plants planted above-ground.