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Seminar: Amanda Lay-Walters: Impact of Pre-Plant Fertilizer Rates in Combination with Polysulphate® on Yield, Soil Nitrogen Distribution, and Physiology of Strawberry (Fragaria x ananassa ‘Camarosa’ & ‘Chandler’)
November 5, 2021 | 8:00 am - 9:00 am
Amanda Lay-Walters, MS Seminar
Friday, November 5, 2021, 8:00 am
(Under the direction of Dr. Mark Hoffmann and Dr. Michelle Schroeder-Moreno, Co-chairs)
121 Kilgore Hall / Hybrid
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Meeting ID: 968 9273 4016
Annual hill plasticulture systems are the primary production method for strawberry (Fragaria x ananassa) in North Carolina (NC). Approximately 1,200 acres of strawberries are grown in NC in plasticulture systems, mostly for direct-to-consumer markets. Young strawberry plants are transplanted every year in September/October and need to be established in order to produce fruit the next Spring. Therefore, fertilizers for this system are usually applied in two steps: In Fall, before bed-shaping and transplanting as so-called pre-plant fertilizer (often granular), and in the following Spring, during bloom and fruiting as liquid fertilizer through a drip line. It has been widely established that oversupply of Nitrogen (N) during the pre-plant phase results in loss of excess fertilizer, lead to environmental pollution and increased cost to the grower. NC Department of Agriculture and Consumer Service’s current recommendations to apply 67 kg/ha (60 lbs/ac) of N as pre-plant fertilizer are believed to provide excess N in strawberry production systems. To investigate this, four field experiments and one greenhouse experiment were conducted between 2019 and 2021. In all field experiments, 6 pre-plant treatments were established (4 replicates per treatment): 1 (67.25 kg/ha), 2 (54.14 kg/ha), 3 (41.09 kg/ha), 4 (27.98 kg/ha), 5A (33.63 kg/ha), 5B (80.1 kg/ha), 6 (NTC), 7 (SCC), and 8 (SCC+PH) and soil samples were taken in different depths at each replicate over the first 5 months of plant establishment. Further, plant tissue samples were collected to analyze for N concentration. Later in the season, strawberry yield was assessed. In the greenhouse experiment, plant development, chlorophyll, nutrient content of tissue and substrate, and dry weight of above and below ground biomass was analyzed. This study shows that pre-plant N rates rapidly declined under plastic within the first 4 weeks and did not impact strawberry yield. Moreover, we showed that higher pre-plant N rates do not result in the complete use of N by the plant in the first 12 weeks after planting. We conclude that current recommendations of pre-plant N rates for NC plasticulture strawberry are too high. While future research on precise fertilizer rates is necessary, we believe that pre-plant N rates can be adjusted to lower that recommended rates for the strawberry cultivars Camarosa and Chandler.