Drip irrigation of waxy corn (Zea mays L. var. ceratina Kulesh) for production in highly saline conditions

A 4-year trial was set up to test the feasibility of growing waxy corn (Zea mays L. var. ceratina Kulesh) in a highly saline wasteland with drip irrigation in the Ningxia plain, northwest China. The original soil salinity expressed as electrical conductivity of the saturation paste extract (ECe) averaged 28 dS/m in the 0–120 cm depth. The experiment included five soil matric potential (SMP) treatments in which the SMP at 20 cm depth below the drip emitters was controlled higher than −5, −10, −15, −20 and −25 kPa after waxy corn establishment. The results showed that drip irrigation created a favorable soil condition for waxy corn growth through forming and maintaining a high moisture and low salinity region in the root zone when the SMP was maintained higher than −25 kPa. Waxy corn growth and yield parameters increased with the increase of SMP from −25 kPa to −5 kPa, but their responses to SMP decreased with the prolonged period of cultivation. Irrigation frequency and irrigation amount decreased significantly as SMP decreased from −5 kPa to −25 kPa, and the highest irrigation water use efficiency (IWUE) was available when the SMP was around −15 kPa in 2005, and was between −20 kPa and −25 kPa in successive years. After years of cultivation and drip leaching, the highly saline soil gradually changed to a moderately saline soil. This research suggests that drip irrigation can be successfully used in growing waxy corn in dry and highly saline conditions after appropriate management strategies are adopted.