@article{lay-walters_heagy_woodley_hoffmann_2024, title={Impact of Pre-Plant Fertilizer Rates in Combination with Polysulphate® on Soil Nitrogen Distribution and Yield of Short-Day Strawberries (<i>Fragaria</i> x <i>ananassa</i> cv. Camarosa)}, volume={14}, ISSN={["2073-4395"]}, url={https://www.mdpi.com/2073-4395/14/4/774}, DOI={10.3390/agronomy14040774}, abstractNote={Strawberries are by far the most produced soft fruit (blueberries, raspberries, blackberries, and strawberries) worldwide, with China and the US being the two countries with the most production. In the US, strawberries reached a farm gate value of more than USD 3 billion in 2023 and are predominantly grown in the open field on an annual cycle in hilled-up soil beds using plastic mulch (plasticulture). This process relies on adequate pre-plant fertilizer application for plant establishment and fruit development. In North Carolina (US), it is current practice to apply pre-plant fertilizer containing 67 nitrogen (N) kg/ha; however, with increasing fertilizer costs and environmental concerns, questions remain as to whether or not pre-plant full-spectrum fertilizer rates can be reduced and substituted with organic low-N fertilizer sources, such as Polysulphate, without impacting yield or fruit quality. For this reason, field trials were established to evaluate the impact of pre-plant fertilizer rates on strawberry production (‘Camarosa’). Trials were conducted in the 2019–2020 and 2020–2021 seasons at two locations in North Carolina. The following N-rate pre-plant fertilizer treatments were applied: 80.1, 67.3, 54.1, 41.1, 33.6, 28.0, and 0 kg/ha. NO3 and NH4 content were frequently assessed in each replicate in the raised bed profile between planting and spring fertilizer application. Marketable and total strawberry yields were assessed over 6 weeks in the spring of 2020 and 2021. Our trial results showed that, especially in sandy soil, N rapidly declined under plastic within the first 8 weeks after pre-plant fertilizer application. However, no impact between pre-plant fertilizer rates and plant yield was observed. Treatments that contained Polysulphate and lower amounts of full-spectrum fertilizer showed significantly lower N concentrations in the soil while maintaining similar yields and fruit quality compared to grower-standard pre-plant fertilizer treatments. In summary, our results show that it is possible to reduce N content in pre-plant fertilizer by up to 50% compared to current recommendations without causing yield loss in short-day strawberry cultivars.}, number={4}, journal={AGRONOMY-BASEL}, author={Lay-Walters, Amanda and Heagy, Kimberly and Woodley, Alex and Hoffmann, Mark}, year={2024}, month={Apr} }
 @article{heagy_schultheis_birdsell_knuth_ward_2023, title={High-density Planting and a Smaller Row Width Increased Yield and Decreased Fruit Size of}, volume={58}, ISSN={["2327-9834"]}, DOI={10.21273/HORTSCI17246-23}, abstractNote={Pumpkins (Cucurbita sp.) grown in North Carolina are a nascent specialty crop that has only risen to a national production level in the past 10 years. There are only general cultural management guidelines for this region, resulting in variation in plant density and inefficient production. Production field studies of the cultivar Kratos were conducted to investigate the impact of plant density and row width on marketable yield and individual fruit size for large carving pumpkins. Plant densities of 2691, 3588, 5382, and 10,764 plants per hectare with row widths of 1.5 and 3.0 m were grown in 2020 and 2021 in North Carolina. Data regarding fruit size, fruit size variance, and yield per area were collected. Fruit size in terms of weight, length, and diameter increased as plant density decreased. There was no difference in fruit size variation between plant densities and row widths. The fruit number per hectare and fruit weight per hectare increased as plant density increased, with the highest production at 10,764 plants per hectare. For years combined, reducing the row width from 3.0 to 1.5 m increased the fruit weight and diameter, but not the length. Additionally, the 1.5-m row width produced more fruit weight per hectare than the 3.0-m row width for both years. Growers can optimize fruit weight per area and fruit number per area by using a density of 10,764 plants per hectare. Overall, using a row width distance that is more equidistant to the in-row spacing promotes higher fruit yield and larger fruit size.}, number={10}, journal={HORTSCIENCE}, author={Heagy, Kimberly and Schultheis, Jonathan R. and Birdsell, Travis and Knuth, Melinda and Ward, Jason K.}, year={2023}, month={Oct}, pages={1194–1200} }
 @article{heagy_knuth_schultheis_birdsell_ward_2023, title={Using Partial Budgeting Analyses to Analyze Profitability of Commercial Pumpkin Production, Standardize Bin Size Categories, and Understand Bin Sorting Accuracy}, volume={58}, ISSN={0018-5345 2327-9834}, url={http://dx.doi.org/10.21273/hortsci17499-23}, DOI={10.21273/HORTSCI17499-23}, abstractNote={Pumpkins (Cucurbita sp.) are currently sold in retail commercial bins categorized based on fruit size. There are no standards for these fruit sizes, thus creating discrepancies across the industry. Furthermore, there is not a published partial budget analysis for pumpkin fruit yield based on plant area. An observational study was conducted to quantify and standardize the fruit sizes of pumpkins packed into commercial bins. These proposed standardized fruit sizes were then correlated to the expected fruit size and quantity of different plant areas to estimate the total commercial bin yield. Additionally, a partial budget analysis was conducted to calculate the greatest profit per hectare with the varying plant areas. Pumpkins from bins labeled medium, large, extra-large, and jumbo were hand-measured to determine the diameter, length, and weight. Based on a discriminate analysis, 20% of pumpkins were incorrectly sorted based on current practices. The proposed standard fruit diameters for each bin size are as follows: medium, 23.5 to 26.8 cm; large, 26.9 to 29.9 cm; extra-large, 30.0 to 33.6 cm; and jumbo, 33.7 to 35.5 cm. The results of a partial budget analysis showed that the most profitable plant spacing area is 0.9 m2 with a 1.5-m row width, which will earn $37,163/ha. Profit for pumpkin production is contingent on both fruit quantity and fruit size because these factors dictate the quantity and category of commercial bins. Growers should consider both metrics to optimize their operation.}, number={12}, journal={HortScience}, publisher={American Society for Horticultural Science}, author={Heagy, Kimberly and Knuth, Melinda and Schultheis, Jonathan R. and Birdsell, Travis and Ward, Jason}, year={2023}, month={Dec}, pages={1587–1594} }