Irrigation Methods and Nitrogen Fertilizer Application Strategies for Potato

There are approximately 300,000 ha of irrigated land under seepage in Florida. Seepage uses groundwater to maintain a shallow water table leading to a low irrigation efficiency compared to other irrigation methods. Alternatively, subirrigation with drain tile (SDT), subsurface drip irrigation for water table control (SDI), and sprinkler irrigation (SI) methods have been introduced in Florida through governmental cost-share programs to improve water conservation. The objectives of this study were to evaluate the use of SDT, SDI, and SI as alternative irrigation methods to seepage, and to determine proper N-fertilizer timing and rate strategy for potato in each irrigation method. A factorial RCBD of three N-rates (0, 56 and 112 kg ha^-1) applied at planting, two N-rates (56 and 112 kg ha^-1) applied at emergence and tuber initiation (12 treatment rates ranging from 112 to 336 kg ha^-1) was setup in each irrigation method in 2015 and 2016 in Hastings, FL. Crop evapotranspiration averaged 270 mm and cumulative rainfall 239 mm. Total average water applied was 291, 169, 145, and 93 mm for seepage, SDT, SDI, and SI, respectively. There was no interaction between irrigation methods and N-treatments on tuber yield. Total tuber yield averaged 32.2, 37.2, 34.7, and 33.3 Mg ha^-1for seepage, SDT, SDI, and SI, respectively. The application of 56, 112 and 56 kg ha^-1of N at planting, emergence, and tuber initiation timing resulted in similar yield than higher N-rates regardless of irrigation methods. Alternative irrigation methods reduced water application in 42-68% and maintained tuber yield compared to seepage.