2018 ASHS Annual Conference

Strawberry (Fragaria ananassa) is a major component of North Carolina agriculture. Strawberry production in the state ranks fourth in the United States, with a total of 2,000 acres in production. Traditionally, the North Carolina strawberry season only has a five to seven-week harvest period that begins in April. Most of the berries produced are grown in an annual plasticulture system with several June-bearing cultivars. Strawberries have proven to be economically sustainable in North Carolina and are popular with consumers year-round. The objective of this study was to investigate if growth and yield will be enhanced by increased nitrogen levels for day-neutral cultivars, paired with low tunnels targeting both fall and spring harvests. In the fall of 2017, research was conducted at the Sandhills Research Station (Jackson Springs, NC) with the day-neutral cultivar Albion. Plugs were planted in standard plasticulture system with low tunnels installed over the beds. The experimental design was a completely randomized design with three replications. Treatments included a single broadcast pre-plant dry application (60 lbs/acre) and eight weekly drip-applied applications (0, 3.5, 7, and 10 lbs/acre). There were substantial interactions in both plant growth and yield with increased nitrogen rates. Market yields were maximized with total nitrogen at 140 lbs/acre with 60 lbs/acre applied pre-plant as a broadcast granular and 80 lbs/acre applied through fertigation for eight weeks, beginning at first bloom. Yield ranges were 0.092, 0.131, 0.137, and 0.168 lbs/plant, yield increase was consistent with increased nitrogen; however, tissue analyses with leaf petioles showed that there was no significant difference in terms of NO₃-N between treatments. Biomass of crowns, leaves, and roots increased with nitrogen rate similar to the market yield. Our preliminary results suggest that growers can get a reasonable fall yield from day-neutral cultivars grown under low tunnels and fed at a relatively higher nitrogen rate.