Effect of subsurface irrigation systems on water use efficiency and soybean growth

Background: Water stress during the critical growth periods reduces crop yield and quality. The present study was evaluated the effect of subsurface irrigation systems on water use efficiency and soybean growth at sandy-loam soil.

Methods: Tractor attachable dripline injector was used to install the dripline to the each plot at NICS research field in Miryang, Korea. Five irrigation treatments including the control were applied in response to application wide (70 and 140cm) and position (under ridge and furrow). Each plot contained twelve crop rows, 38m in length and 70cm row spacing.

Results: Soil water content at top 10cm was significantly greater than the control, which was significantly increased to 15.8% with 70cm interval under ridge, 19.1% with 70cm interval under furrow, 21.0% with 140cm interval under ridge, and 24.6% with 140cm interval under furrow, respectively. Soybean yield components including plant height and stem thickness were strongly influenced by irrigation practices. Chlorophyll concentration was also greater with irrigation practice compared to the control in whole growth stages. The highest grain yield was 3.35 ton/ha with 70cm interval under ridge plot, which was 34% more yield compared to the control.

Discussion: Soybean yield components and grain yield were significantly influenced by irrigation practices due to the plant favourable soil management such as timely water supply. The design of subsurface irrigation system has different water use efficiency during the soybean growth periods.

Conclusion: The results of this study indicate that the subsurface irrigation system is one of the best management options for soybean cultivation in sandy-loam soil. Although soybean would not be considered a typical crop for subsurface irrigation in Korea, the some advantages including yield increase can be a large counterbalance against the extra irrigation cost.