Timing of climatic factors that may influence potato yield, quality, and potential nitrogen losses in a northeast Florida seepage -irrigated potato production system.

摘要

Potato, a cool season crop, is planted in Northeast Florida in January when temperatures are cool. As the season progresses, daily temperatures and incidence of leaching rainfall events increase which can affect yield and quality. Nutrient runoff from potato production land has thought to have been primarily responsible for the non-point source pollution into the St. Johns River watershed. Best Management Practices (BMPs) for potato production in the TCAA have been implemented. With over 7,000 ha in potato production in the TCAA, the main concern with the implementation of the BMPs are to not compromise yield and quality. The experimental design in chapter 2 was a split-split design with four blocks. Planting dates (1-6) were main plots. The first split was the N rate (168 and 224 kg ha-1). The second split was potato variety, 'Atlantic' and 'Harley Blackwell'. The experimental design in chapter 3 was a split-split design with four blocks. Irrigation treatments were main plots at 0, 2, 4, 8, and 12 WAP (weeks after planting). The first split was the nitrogen source (AN or CRF). The second split was an additional side-dress fertilizer application. Optimal yields for the TCAA occurred over a 4 week period (early to late February) in a twelve week planting window. 'Harley Blackwell' demonstrated its effectiveness to produce quality tubers under conditions when air temperatures and leaching rainfall events stressed plants. IHN was triggered by rainfall and nutritional conditions that stressed the plant early in the season combined with increasing minimum daily temperatures later in the season. Marketable yields in the CRF treatments were an average of 12% higher compared with the AN fertilizer treatment. The CRF treatments had a significantly higher incidence of tubers with IHN compared with the AN fertilizer treatment at 22.3 and 15.6%, respectively. NO3-N loading from surface water runoff from potato production was decreased an average of 43% with the use of the CRF compared with the AN fertilizer treatment. A CRF used in potato production, rather than a soluble N fertilizer, could reduce NO3-N loads into the St. Johns River watershed by 56,000 kg N per year.