Subsurface banding poultry litter influences edamame yield, forage quality, and leaf greenness

Authors: Ashworth, Amanda; Nieman, Christine; Adams, Taylor; Franco, Jose; Owens, Phillip

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/24/2022
Publication Date: 4/29/2022
Citation: Ashworth, A.J., Nieman, C.C., Adams, T.C., Franco Jr, J.G., Owens, P.R. 2022. Subsurface banding poultry litter influences edamame yield, forage quality, and leaf greenness. Agronomy Journal. 114(3):1833-1841. 10.1002/agj2.21048.
DOI: https://doi.org/10.1002/agj2.21048

Interpretive Summary: Poultry litter (or excreta plus bedding and dead birds) land application has the proven ability to substantially increase crop yields and enhance soil health. However, surface applications have been scrutinized for water quality reductions from excess phosphorus runoff into neighboring waterbodies. In efforts address these concerns and improve management options that prevent nutrient losses and aid in efficient poultry litter usage, a research team at the United States Department of Agriculture, Agricultural Research Service developed a prototype tractor-drawn implement for subsurface band application of dry poultry litter in conservation tillage systems. This 'ARS Subsurfer' has proven success in perennial pasture systems, but little information exists on appropriate crop seeding distance from poultry litter bands to increase crop yield, quality, and leaf greenness in row crops. In addition, Arkansas is currently the top edamame producer in the U.S and interest in its production continues to grow, particularly for organic small farm producers. Therefore, researchers set out to evaluate i) edamame planting distance from subsurface litter bands for optimum crop yield, quality, and leaf greenness under rainfed and irrigated conditions, and ii) identify the potential for edamame residue to serve as fodder for integrated crop-livestock systems. Authors found that all subsurface banding treatment distances had greater total yields than surface applied poultry litter. Great amounts of available crop residue (of similar nutritive value to regional fall stockpiled forages) suggests that edamame could be used as a dual-use (vegetable and fodder) crop. Overall, adoption of subsurface banding poultry litter (relative to surface applications) will enhance soil, water, and nutrient conservation, particularly in dual-use organic edamame specialty crop and fodder systems.

Technical Abstract: Poultry litter is generated in large quantities throughout the southeastern U.S. and is an excellent soil amendment for increasing crop yields; however, surface applications may result in nutrient losses to air, soil, and water. Subsurface banding poultry litter, a novel nutrient management strategy, is a promising technology for reducing nutrient losses to surface and groundwater while improving yields, but information is needed on optimum crop seeding distance from bands. This study evaluates edamame (Glycine max 'Edamame') yield, crop quality, and leaf greenness based on subsurface banded poultry litter and planting distances (13, 25, and 38-cm) compared to surface-applied poultry litter (control) under irrigated and non-irrigated conditions from 2019 to 2020. Both chlorophyll and edamame pod yields were greatest (P = 0.05) under subsurface banding litter, relative to surface applications, regardless of distance. Overall, greatest yields were observed for 25 and 38-cm banding distances under both rainfed and irrigated systems, relative to surface applications. Residue nutritive value for the 13-cm distance was greater under irrigation than dryland; although, both systems provided high levels of nutritive residual mass, thus edamame can be utilized as a vegetable crop and a potential forage following harvest. Overall, subsurface banding poultry litter either 13, 25, or 38-cm distances from poultry litter bands in conservation tillage systems is a viable replacement for surface applications for multifunctional edamame (vegetable and fodder) production, particularly in organic production. These results can be used to develop nutrient management plans for organic edamame and other specialty crop production systems.