Recipient Organization
UNIVERSITY OF ARKANSAS
(N/A)
FAYETTEVILLE,AR 72703
Performing Department
Horticulture
Non Technical Summary
Aggressively growing weeds can quickly outgrow specialty crops, robbing the crop of light, nutrients, and water. Specialty crops are particularly vulnerable to weed interference because of the specific light and nutrient needs of at critical growth stages, such as flowering, fruit set, and fruit-swelling (Welbaum 2015). When weeds compete for these limited resources, resulting deficiencies cause aborted fruit, misshapen fruit, or other reductions in fruit quality (Bertucci et al. 2018; Patten and Wang 1994). Misshapen or undersized produce will not meet market standards and will be rejected by contractors or consumers. Marketable yields are dramatically reduced when problematic weeds such as Palmer amaranth invade watermelon (Bertucci et al. 2019), sweetpotatoes (Meyers et al. 2014), or cucumber (McGowen et al. 2018). Thus, economically sustainable production of specialty crops is predicated on a successful weed management strategy.Specialty crop producers face novel challenges with wider adoption of organic production, the phase-out of methyl bromide, and climatic changes (Ngoaujio 2005). Specifically, weeds have been surveyed as one of the greatest barriers to organic production (Walz 1999). These surveys and novel issues for specialty crop production emphasize the need for improved integrated weed management strategies.Of further importance is the need for integrated weed management strategies that control weeds and prevent weed outbreaks in subsequent growing seasons. Due to extensive seed production and seed dormancy, weed populations from one year can cause problems for many years in the future (Zimdahl 2013). Spatial models indicate that a single escape weed could quickly repopulate an entire field if left uncontrolled (Norsworthy et al. 2014). Thus, integrated weed management strategies must be evaluated independently and in combination for the overall effect on weed populations.
Animal Health Component
80%
Research Effort Categories
Basic
20%
Applied
80%
Developmental
(N/A)
Goals / Objectives
The long-term goal of this project is evaluate the relative efficacy and utility of integrated weed management strategies in Arkansas fruit and vegetable production. Specifically, this project will assess the performance of integrated weed management practices focused on sustainable production practices, such as propagation methods favoring rapid crop establishment or prevention of weed encroachment through the use of cover crops. Through this project, we will develop and evaluate integrated weed management strategies for improved economic and environmental sustainability of specialty crops. Our overall objective is to expand and increase specialty crop production by minimizing losses due to competitive weed populations.
Project Methods
All research will center on replicated field trials carried out across multiple years and environments, ensuring repeatability and application for producers across the state. Field trials and demonstrations will be executed at the Milo J. Shult Research and Extension Center in Fayetteville, the Vegetable Research Station in Alma, the Fruit Research Station in Clarksville, and the Southwest Research and Extension Center in Hope.Initial field trials will evaluate the performance of a cereal rye cover crop in combination with preemergent herbicides in watermelon production. This trial will be planted in Alma, AR at the Vegetable Research Station. Cereal rye cover crops will be sown in the fall and maintained through the following spring. The cover crops will be randomized and drill-seeded in 12 ft passes. Within the same field and randomization pattern, 12 ft strips will be left fallow. Cover crops will be terminated with a roller-crimper and application of glyphosate. Watermelon seeds will be initiated in greenhouses and transplanted into the field in the following summer. Herbicide treatments will include a selection of federally-registered herbicides (carfentrazone, halosulfuron, S-metolachlor) and will be compared to an untreated check receiving no herbicide. Thus, the experimental design will be a split-plot with cover crop serving as the whole plot and herbicide as the split plot (within each cover crop). Experimental units will be 10 watermelon plants at 30-in in-row spacing on 12-ft centers. Herbicide applications will accomplished using a CO2-powered backpack sprayer to broadcast herbicide treatments across their respective plots 48 h prior to watermelon transplanting. Weed control will be assessed with visual ratings and quantified by harvesting biomass at the end of the season. Watermelon marketable yield and marketable yield will be determined by harvesting ripe fruit (Vinson et al. 2010) and weighing and grading each fruit as marketable or unmarketable, based on previously established grading standards (Schultheis and Thompson 2014).Subsequent work will evaluate the performance of a selection of herbicides on newly established blackberry plantings. The goal of weed control in perennial systems is "to start clean and stay clean" (Burgos et al. 2014), emphasizing the importance of preventative weed control in these systems. However, very few of the herbicides registered for use in blackberry have been evaluated for use in new plantings. Thus, our goal will be to assess the safety and utility of a selection of preemergence herbicides for use in newly established blackberry plantings. This trial will be executed in Fayetteville, AR at the Milo J Shult Research and Extentsion Center and in Clarksville, AR at the Fruit Research Station. 'Ouchita' blackberries will be planted and maintained according to regional fertility recommendation. Applications will be applied using a CO2-powered backpack sprayer to deliver herbicides in 40-in banded strips on each side of a plot. Experimental units will comprise of 5 blackberry plants at 24-in spacing and 8-ft row centers. Weed control will be evaluated using visual assessments and by harvest. Crop tolerance to herbicides will be assessed by visual ratings and vegetative measurements (e.g., SPAD meter, floricane length) and compared to an untreated plot receiving no herbicide.Accessibility and outreach will be prioritized when possible to ensure stakeholders, students, county agents, and other researchers can observe and learn about the research activities associated with the project. Viability of integrated weed management strategies will be assessed based on yields, economic returns, and soil health. Findings will be published in extension web portals, classroom activities, extension fact sheets, scientific journals, and field days.