Effect of Nitrogen Application and Fertigation Scheduling On Potato Yield Performance Under Drip Irrigation System

Abstract

The drip irrigation method offers the potential of higher application efficiency of water and allows precise placement of fertilizer directly in the root zone. The use of drip irrigation also facilitates the frequent application of fertilizer via injection in the irrigation system, which allows the conjunction between nutrient application and time of crop needs. The effect of nitrogen (N) rate and drip fertigation scheduling were evaluated on yield, N uptake, and recovery of potato grown on sandy soil. The N was applied at two rates under regular irrigation (control) or through drip irrigation along with four fertigation schedules including: equal doses applied at the weekly or biweekly intervals and different doses based on growth curve characters (12.5, 25, 50, and 12.5% of the total N amount) at the same intervals, for initial, developmental, mid, and mature stages, respectively. The N rate and wise fertigation scheduling significantly affected yield and yield components except for the tuber number per plant. The higher tuber yield was associated with a higher N rate when the respective nutrient was stage wise scheduled and typically responded to growth curve character than equal scheduling at any time intervals. The increase in yield was higher with wise weekly by 13 and 22% than with equal weekly or biweekly intervals, respectively. For this scenario, the modeled crop uptake at the weekly interval was 16% higher than equal applied at the same interval or even greater by 31% than equal applied at the biweekly interval. Similarly, the higher N rate and wise weekly scheduling increased N recovery and N use efficiency (NUE). Soil N movement with wise scheduling resulted in lesser leaching of NO3−-N to deeper soil layers, particularly with wise weekly scheduling. The framework presented in this study regarding the rate and N scheduling to copy with plant growth curve can sustain high crop yield while reducing NO3−-N leaching, increasing N uptake and recover.