Potato canopy growth, yield and soil water dynamics under different irrigation systems

The aim of this research was to compare two irrigation and N application systems, gun irrigation (GI) and drip fertigation (DF), in terms of soil water dynamics, N uptake, N use efficiency, and yield of table potatoes. Two treatments were set up in a three-year field experiment. Treatments differed by irrigation and N application methods, and scheduling. Water and N management in GI was managed according to typical best-practice while irrigation and N for DF was applied through drip fertigation according to a crop simulation model. Results showed that DF provided high soil water content at the center of the ridge. Average soil water content across the ridge soil profile was higher for DF than GI. Compared to DF, GI led to relatively high canopy growth early in the season through applying all N at planting, while the opposite trend was detected later in the growing season. Tuber yields in GI were 46, 43 and 44 t ha−1 in 2013, 2014 and 2015, respectively. Tuber yields in DF were 48, 43 and 40 t ha−1 in 2013, 2014 and 2015, respectively. There was no significant difference in yield between systems for any of the three seasons of the experiment. However, DF led to significantly higher tuber N recovery and agronomic N use efficiency in one of the years (2013). In addition, GI caused greater nitrate leaching during the growing season in both 2013 and 2014, as measured by suction cups and simulated by the Daisy simulation model.