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Some agricultural areas of northeast Florida have converted from seepage irrigation to tile drainage, subsurface drip irrigation for water table control or overhead sprinkler irrigation. Growers are converting to these alternative irrigation systems to increase irrigation water savings. However, because of the low nitrogen use efficiency of potatoes and the susceptibility of N losses in the sandy soils of the region, high N fertilizer rates may still be required to maintain potato yields. The objective of this study was to evaluate irrigation water and N requirements, soil water dynamics of alternative irrigation systems compared to seepage irrigation. A field experiment was conducted at the University of Florida, Hastings Research and Extension Center using seepage, tile, subsurface drip, and overhead irrigation. Treatments combining N fertilizer rates of 0, 56, 112 kg/ha were applied at planting and 56 or 112 kg/ha were applied at both the emergence and side dress application within each irrigation system in a factorial randomized complete block design with four replicates. The average potato yield was 35.8, 37.4, 40.6 and 39.1 t/ha for seepage, tile, subsurface drip and overhead irrigation, and irrigation water use efficiency of 11.8, 25.3, 31.6 and 36.3 kg/m3, respectively. Irrigation water savings were 51%; 58% and 68% with tile, subsurface drip and overhead irrigation, respectively, compared to seepage irrigation. The application of 56 and 112 kg/ha N fertilizer at potato planting resulted in significantly higher tuber yield compared to the 0 kg/ha N treatment in all irrigation systems. The highest potato yield was achieved with the total N-fertilizer treatment rates above 224 kg/ha. There were no significant differences in tuber yield for total N rates between 224 and 336 kg/ha. Alternative irrigation systems produced similar or higher tuber yield with low irrigation water requirements, while N application timing rates played important role in potato tuber yields. |