Fertigation Significantly Increasing Yield of Overhead Irrigated Potato in Florida.

Potato is an important spring crop grown in Florida. Seepage irrigation and dry granular fertilization are mainly adopted for commercial potato production. For this traditional practice, fertilizers are generally applied three times: pre-plant, at emergence, and in tuber initiation. Seepage irrigation is such a practice: a large volume of groundwater is pumped out to keep the water table between 46 and 61 cm from the soil surface. This irrigation practice is poorly efficient in water use. On the contrary, overhead irrigation through center-pivots or linear pivots is significantly more efficient in water use than seepage. Since overhead irrigation supplies water to the crop from the top, the combination of overhead irrigation and dry granular fertilization leads to more nutrient leaching and lower yield. To increase tuber yield for overhead irrigation, fertigation is proposed to replace the third dry granular fertilization of the aforementioned traditional fertilizer program. Two treatments were employed side-by-side for this study: fertigation and dry granular fertilization. The former included two dry granular fertilizer applications: pre-plant and at emergence and a liquid fertilizer application through the irrigation system in tuber initiation. The latter was the traditional fertilizer program potato growers had been using for generations. The results showed that fertigation (49.78 ± 7.08 Mg/ha) increased tuber yield by 16 % compared to dry granular fertilization (42.97 ± 10.62 Mg/ha) for chipping potato ‘Atlantic’ in the 2015~2016 growing season. Similarly, fertigation (49.02 ± 0.98 Mg/ha) yielded 24% more tubers than dry granular fertilization (38.46 ± 3.59 Mg/ha) for fresh table-stock potato ‘Red LaSoda’ in the 2016~2017growing season. The data indicate that fertigation can significantly improve tuber yield for both chipping potato and fresh table-stock potato grown on sandy soil in Florida.