Recipient Organization
NORTH CAROLINA STATE UNIV
(N/A)
RALEIGH,NC 27695
Performing Department
Horticultural Science
Non Technical Summary
Summary:Agriculture is important to NC and contributes $92 billion dollars to the state's economy. It also provides about 728,000 jobs, which is 17% of all jobs in NC. It is the second largest sector that employs people in NC only behind education and health care (945,000 jobs). Vegetable production is one sector that contributes to agriculture with over ½ billion dollars annually and is a way of life for many in NC. For the vegetable industry to continue to thrive, it is critical that the best varieties adapted to NC growing conditions and alternative production management practices be identified to keep the industry profitable. This project will regularly evaluate watermelon, melon, squash, pumpkin and sweetpotato varieties and will communicate with industry those varieties that offer the best opportunities to achieve superior yields and quality. The growth of the NC sweetpotato industry has been substantial over the last decade and continues to foster the development of new products beyond fresh market and domestic sales. Nearly 50% of sweetpotatoes grown in NC are shipped overseas as table stock for consumption. Products such as beverages, cereals, pet food, and fries have increased the market for this crop. New sweetpotato cultivars are being developed which provide new marketing opportunities. Organic clones with improved insect resistance provide farmers with a better opportunity to stave of insect pests in this production system. Purple flesh clones provide nutrition advantages, while new orange flesh clones are being bred for specific processing market needs. These new sweetpotato clones are all being evaluated as part of this project and the end products will provide producers with new marketing opportunities and consumers with new and improved food products. Sweetpotato growers need to produce their crop in a more efficient manner reducing production costs and to meet the increasing demands for sweetpotato. New tools such as alternative planting strategies which utilize potentially more efficient transplanting equipment to increase yield, or the use of drone surveillance equipment to monitor fields provide growers with assistance to better produce their crop. More simple strategies such a packing sweetpotato rows closer together offers the opportunity to improve yields and production efficiency.New emerging NC markets for pumpkin need to be supported to remain profitable and competitive. Identifying new traditional jack o'lantern types of pumpkin that have improved yields and pest resistance are important to maintaining and increasing markets. Improving management by altering plant spacing, and improving nitrogen and disease management are important steps to the stable, consistent production of an annual NC pumpkin crop. New pumpkin types like blue and white pumpkins which have superior yields and quality offer additional marketing opportunities.The importance of having good plant nutrition when producing a crop is always paramount to success. Several products provided by industry to improve productivity of a crop will be evaluated. One study includes some products from Yara in which major and minor nutrient programs are considered with the goal of increasing sweetpotato productivity. Another issue is the conservation of these nutrients. One study evaluates the use of microbes designed to maximize nitrogen availability and reduce nitrogen use which potentially can preserve the environment from over application of nitrogen. Finally, potash is another important nutrient which is used extensively to produce most crops, including sweetpotatoes. A better understanding as to what rates and times potassium fertilizer should be applied which can result in efficient use of fertilizer and productivity of sweetpotato.The overarching goal of this project is to better position NC growers to produce healthy, nutritious vegetables in an efficient, profitable, and sustainable manner.
Animal Health Component
75%
Research Effort Categories
Basic
(N/A)
Applied
75%
Developmental
25%
Goals / Objectives
Goals/Objectives: The primary goal of this project is to identify genetic materials and develop production practices that result in the sustainable and profitable production of key vegetable crops grown in NC and the southeastern US.Identify and evaluate new genetics that enhances yield, quality, and pest management of sweetpotatoes (SPs) and cucurbits.Evaluate newly developed SP planting equipment with regards to effects on root yield and quality.Improve crop yields and size uniformity by optimizing plant spatial arrangement.Develop the use of drone technology as a tool to aid in crop production management.Identify new fertilizer carriers, amendments, rates, and application times which lead to improved vegetable yields and quality.Justification:1. Genetic evaluations.In order to remain profitable, it is critical that a producer grow the best quality, highest yielding cultivars that have excellent pest resistance and long postharvest shelf life.Selection of outstanding cultivars for production and keeping ability is important in obtaining and maintaining markets. New melon cultivars contain genes that confer long shelf life. Various specialty melon types (galia, canary, honeydew, Tuscan, etc.) require differing visual cues for optimum harvest (Schultheis et al., 2001), but offer new marketing opportunities. Triploid watermelons (WMs) comprised 90% to 95% of the United States WM market in 2018 (USDA, 2019) as their quality continues to evolve and improve. Regular evaluations of new WM cultigens have occurred annually during this past reporting period (Schultheis and Starke, 2020, 2019, 2018). Yield is one of the most important criteria; however, key quality attributes for evaluation are flesh firmness, hollow heart incidence and severity, and total soluble solids. Quality attributes should be coupled with high yielding cultivars.SP is the most economically important vegetable crop to NC accounting for $347.5 million in sales in 2017, and producing over 55% of the crop in the US (USDA, 2018). Annual variations in climate and pests provide opportunity to evaluate clones under various environments to determine how well they grow and yield under different growing conditions. We will evaluate SP, pumpkin (PU), WM, melon and squash cultivars over multiple years due to their economic importance in NC. The state ranks in the US as follows: 1 SP, $347 million; 7 melon, $6 million; 7 WM, $21 million; 8 PU, $13 million; and 8 squash, $10 million. Cultivar recommendations are made for NC and published every year (Kemble et al., 2020).The commercial vegetable industry is interested in having the best possible vegetable recommendations on a timely basis and cultivar studies provide this type of information.2.New SP planting equipment.Use of SP planting equipment to place the transplant into the soil in a vertical orientation is common practice across all US SP producing states (Smith et al., 2009). In a visit to Australia, it was observed that SP transplants were all hand planted horizontally. Horizontal plant orientation results in more nodes of the SP plant in contact with the soil than with the vertical orientation. SP storage roots emanate from the nodes (Firon et al., 2009) and thus if there are more nodes from a plant placed in the soil, yields could potentially be increased. Research was conducted on the orientation of SP plants and how it impacted yield but the results were inconclusive (Monks, 1981). In a recent study in which plants were planted vertically either 2 or 6 inches below the soil line, yields were consistently improved with plants placed deeper in the soil (Thompson et al., 2017). Thus, the hypothesis is that horizontal orientation of plants increases the number of nodes in contact with the soil which may improve yields. Due to the high cost of labor, hand planting of horizontal oriented SP transplants as done in Australia is not feasible for NC growers. To overcome the hand labor cost, an innovative grower Jim Jones developed a planter that places transplants in a horizontal orientation. A sleeve has also been developed that can be attached to a vertical planter. The sleeve attachment causes the transplant to bend parallel to the soil surface potentially resulting in more nodes being in contact with the soil. We propose to re-evaluate questions pertaining to SP orientation by conducting experiments with the newly fabricated SP planting equipment described above.3.Optimize plant spatial arrangement.a. SPA new clone close to release is NC 04-531. The primary target for this clone is the organic market due to its more upright growth habit and insect tolerance. Changes in in-row spacing of 'NC 04-531' were used to improve yields in earlier studies, but did not. Thus, we propose to evaluate between row spacing as a method to improve yields of NC 04-531. By planting rows closer together, more row length will be planted in a given area, thus, theoretically resulting in increased yields per area. Similarly, we propose to evaluate between row spacing on the most commonly NC-grown SP cultivar, Covington.SP in-row spacing has been studied on several clones, with recommended spacing being between 23 to 40 cm (Rubatzsky and Yamaguchi, 1997). There is limited research on between row spacing (Adubasim et al., 2017; Arancibia et al., 2014) but SP research on in-row spacing is more prevalent (Adubasim et al., 2017; Arancibia et al., 2014; Abdissa et al., 2011; Guertal and Kemble, 1997; Mulkey et al., 2004; Schultheis et al., 1999).b. PUPU has become an increasingly important crop in NC with the state ranked as high as fourth nationally with an annual crop value of $18.7 million in 2016 (NC Dept. Agric. & Consumer Sciences, 2017). Much of the PU production in NC is located in northwestern NC; however, the crop is produced across the entire state. Research is needed to improve production practices of PU and keep PU growers competitive and profitable. One production consideration is plant spatial arrangement in which between row and in-row spacings should be evaluated to optimize fruit size and yields.4.Utilizing drone technology to improve production management.Drones, or unmanned aerial vehicles (UAVs) have been widely used by the military since World War II (Stehr, 2015). More recently, UAVs have been used by farmers to monitor their fields for many agricultural applications such as seedling emergence and crop damage assessment; and need for water, fertilizer and pesticide application (weed, insect and disease control) (Stehr, 2015; Van der Merwe et al., 2020).Utilization of 21stcentury drone technology could improve PU production efficiencies. To take advantage of the technology, ground truth is needed to verify what is being recorded digitally by the drone.5. Fertilization of SP.A range of fertilizer products are offered by industry to improve fertilizer efficiency, plant growth and development, and tolerance to disease and abiotic environmental stress conditions in order to maintain or improve crop yields and quality. Growers are interested in determining if these products are of value and should be included as part of their SP management program. Using another approach, microbial inoculants provide the potential to promote plant growth, enhance nutrient availability and uptake and support the health of the plants (Adesemoye and Kloepper, 2009).The SP industry applies a substantial amount of potassium to grow their SP crop (Kemble et al., 2020). There is interest in determining the effects of using potassium carriers at different rates applied at different times on yields. Potassium is involved in numerous physiological processes that control plant growth, yieldand quality parameters such as taste, texture, and health properties (Marschner, 1995; Lester et al., 2005, 2016). Even though potassium is abundant in most soils in the world, both plant and environmental factors often limit adequate plant potassium uptake.
Project Methods
Methods:For all studies, appropriate experimental design and statistical methods will be used such as PROC GLM, LSD, and regression with a minimum of three replications to distinguish differences between treatments (TRs). A partial budget analysis for both the SP and PU studies where the purchase of plants/seeds, the use of machinery, equipment, and labor in planting and harvesting, and yield related factors such as the number of bulk bins will be used to determine the benefit-cost index value.1.Genetic evaluations.WM, melon, PU, and squash cultigens will be evaluated to determine those most adapted for production in NC. Seeds of cultigens will be procured from seed companies. Yield and quality measures will be obtained as appropriate for each specie. Plantings will be at research stations in key NC production regions. Maturity or size differences will be determined among entries, yields with respect to fruit number and tonnage, and critical internal quality measures such as total soluble solids, color, and flesh firmness. With WM, genetic tolerances and resistances to Fusarium wilt will be evaluated. SP clones will be acquired from SP breeding and genetic programs in NC, LA, and USDA. At least eight clones will be evaluated annually with a commercial standard cultivar like 'Covington'. Yields coupled with quality assessment will be used to determine potential for commercialization of clones. SP roots will be graded and weighed, and evaluated for skin and flesh color, shape, uniformity, disease tolerance or susceptibility, and smoothness of skin. In some years, three additional replications of SPs will be planted so that an early and late harvest can be obtained to determine yield gain for each clone.2.New SP planting equipment.Three planter or modified planter types will be compared; 1) vertical planter, 2) horizontal planter, and 3) vertical planter with sleeve. Effectiveness of each planter will be determined with respect to root yield and quality. In addition to evaluating planter type, transplant sizes, based on length will be evaluated for yield response. Average number of nodes for each plant size will be validated and the number of nodes below the soil surface after planting will be determined to assess the relationship between nodes placed in soil with yield. In-row spacing will be another TR variable introduced. An early versus a later harvest will be incorporated in these studies to determine the effects that TRs have on yield and root sizing over time. The primary SP clone evaluated will be 'Covington' while NC 04-531 will also be evaluated. Stand counts will be determined and specific length of row planted to determine yields on an area and per plant basis. An Exeter electronic sizer will grade SP roots.3.Optimize plant spatial arrangement. The standard between row spacing used by most NC SP growers is 42 inches and will be used for comparison of other TRs in this study. Three other between row spacings will be 30, 36, and 48 inches. The 30 inch between row spacing is used in New Zealand. The 36 in-row spacing is being used for the first time by a NC grower in 2020. The 48 inch between row spacing is used by growers who have this equipment to plant tobacco and out of convenience use the same spacing for SP production. Key to conducting this research is to have the proper equipment for each specified between row spacing. Equipment will be acquired using research station equipment and from interested growers. Four row beds will be formed for each between row spacing TR. One of the middle rows or a section of the two middle rows will be harvested to determine yields. Harvested SPs will be graded using an Exeter electronic sizer into various grades that duplicate what commercial SP packing houses use. Yields will be quantified within grades using weights and numbers of roots.Planting arrangements and their effects on PU yields, fruit size and uniformity will be evaluated. Two between row spacing TRs will be 5 and 10 ft. In-row spacing will be varied for each between row spacing such that 10, 20, 30 and 40 square ft are designated for each plant. At harvest, each PU fruit within an area of the middle two rows will be harvested and weighed with the designated harvest area at least one plant from the ends of the plot. This will simulate competition that would be experienced in a commercial planting.4.Utilizing drone technology to improve PU production management.Four rates of N (none, low, medium, and high) will be applied in studies conducted at Laurel Springs, NC. Tissue samples will be collected at least every two wk (5-6 times) to verify the plant nutrient status on the ground with corresponding drone flights made at the same time that tissue samples are taken. PU yields and size for each of the N plots will be measured to determine the best rate of N and corresponding tissue analysis. Drone flights will use a multispectral camera to measure the corresponding color signature of the foliage at a given point in time and determine how spectral analysis equates to plant tissue analysis to potentially be used as a crop management tool. Determination of the color signature of the leaves with respect to detection of powdery mildew (PM), a key disease that if treated in a timely matter, can dramatically increase PU yields. Cultivars that have varying PM resistance will be selected to differentiate color signatures from drone flights. Ground truthing of PM and its occurrence and intensity will be monitored with corresponding drone flights that will be conducted when ground assessments are made during the growing season. Spectral analysis will be matched to disease incidence that is occurring on the ground and used as a proof of concept to potentially manage PM when detected. PU yields and size will be quantified using drone technology approximately two wk prior to harvest. The PU plant spacing study described in the optimize plant spatial arrangement section will be used to assess fruit numbers and sizes which should vary considerably due to spacing TRs. PU fruits within the marked harvest area will be clearly identified and fruit weight, length and width will be measured. Corresponding measures of each PU from a drone fly over will determine how well the fruit sizes obtained from the drone flight correlate with the ground measures. Information gained from this technology should enable more precise fertilization, more timeliness of crop protectant application for PM control, and an early assessment of crop yields and size.5.Fertilization of SP.A standard grower N fertilizer program will be compared with Yara brand fertilizer. Inclusion of various micronutrient formulations (i.e., Agripotash) will complement the N fertilizer applied. Tissue samples will be taken at periodic intervals to determine the amount of nutrient absorption of the various nutrients with respect to TR. An experimental PSH product claims to reduce N use by 20 to 40%. PSH is composed of N fixing microbes that convert multiple forms of N into nitrates which alter the soil microbial environment for favorable N uptake. A control TR would use the amount ofN fertilization a typical farmer uses to grow SPs (~75 lb N/ac). Four additional TRs will include PSH application in which all standard grower practices are followed except the amount of N being applied. N would bereduced by 20%, 30%, 40% and 50% in the four other TRs. Muriate of potash and potassium nitrate will be compared at rates of 0, 150, 225 and 300 lb/acre. Potassium fertilizer will be applied at three intervals and tissue samples taken four times during the production season to determine the potassium content. SP roots will be harvested, graded, and weighed to determine the effects that the fertilizer products have on yield. Roots will be collected, cured, and weight loss measured over time to determine if potassium affects moisture retention and influences disease incidence.