A sowing method for subsurface drip irrigation that increases the emergence rate, yield, and water use efficiency in spring corn

Subsurface drip irrigation is an advanced water-saving irrigation method. However, as a result of driplines being buried below the plow layer, sprinkler systems are usually used to ensure crop germination in arid and semi-arid regions. This study proposed a sowing method called alternate row/bed planting with a 10 cm deep trapezoidal furrow; seeds were then sown in 5 cm deep soil below the furrow bottom. A series of field experiments were conducted, including two sowing methods, namely alternate row/bed planting (AP) and flat planting (FP), at two dripline burial depths (30 (D30) and 35 cm (D35)). The following results were obtained: AP significantly increased the 5 cm soil depth moisture content below the seeds. The emergence rates at burial depths of 30 and 35 cm under AP increased by 15.2% and 9.5%, respectively, compared with those under FP. At the seedling stage, the plant height, leaf area index and dry biomass under AP were significantly higher than those under FP. At a burial depth of 30 cm, the effective ears number, yield, water use efficiency and nitrogen partial factor productivity under AP increased by 12.6%, 14.8%, 11.8% and 14.2%, respectively, compared with those under FP. At a burial depth of 35 cm, the above indexes under AP increased by 10.3%, 5.2%, 4.4% and 5.0%, respectively, compared with those under FP. Overall, alternate row/bed planting for subsurface drip irrigation can considerably increase the emergence rate of spring corn, promote growth at the seedling stage, and increase the yield, water use efficiency and nitrogen partial factor productivity, particularly in arid and semiarid regions where severe spring droughts frequently occur.