Location: Poultry Production and Product Safety Research
Title: Root decomposition and nutrient dynamics in multifunctional forage-biomass buffer-strip systemsAuthor
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AMORIM, HELEN - University Of Arkansas |
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Ashworth, Amanda |
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Adams, Taylor |
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SAVIN, MARY - University Of Arkansas |
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Moore Jr, Philip |
Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 11/25/2024 Publication Date: 1/13/2025 Citation: Amorim, H., Ashworth, A.J., Adams, T.C., Savin, M., Moore Jr, P.A. 2025. Root decomposition and nutrient dynamics in multifunctional forage-biomass buffer-strip systems. Agrosystems, Geosciences & Environment. 8(1). Article 370030. http://dx.doi.org/10.1002/agg2.70030. DOI: https://doi.org/10.1002/agg2.70030 Interpretive Summary: Root decomposition is a major source of carbon entering soils, which helps improve water storage, reduces atmospheric CO2, and improves crop yield, all of which improves agricultural sustainability outcomes. However, it is largely unknown what factors drive root decomposition and CO2 gas exchange in soils. To address this gap, researcher set out to measure root decomposition and CO2 gas release from four multi functional forage-biomass species [two native perennial grasses (switchgrass and eastern gamagrass) and two newly released perennial species (kernza or perennial wheat and silphium)]. Overall, adding nutrient rich poultry litter tended to speed up decomposition resulting in greater organic carbon storage. Also, the newly released perennial crops Kernza and silphium had accelerated decomposition over the 12 month study, which improved carbon sequestration, even greater than native warm season grasses (switchgrass and gamagrass). This research improved our understanding of how root decomposition either aids in CO2 gas exchange or increases carbon storage in soils. Findings from this study help untangle complex soil-root interactions and highlight the potential of novel perennial species to enhance carbon storage, nutrient cycling, and provisioning of ecosystem services in forage-biomass systems. Technical Abstract: Assessing root decomposition dynamics and root-derived C and nutrient inputs in soils is critical to predicting the potential of agroecosystems for C sequestration and provisioning of ecosystem services. Yet, the drivers of root decomposition and subsequent C allocation in perennial multifunctional buffer-strip systems as affected by fertility management are poorly elucidated. Thus, study objectives were to assess root decomposition and soil CO2 efflux on switchgrass (Panicum virgatum), eastern gamagrass (Tripsacum dactyloides), silphium (Silphium integrifolium L.), and intermediate wheatgrass ‘Kernza’ (Thinopyrum intermedium) treated with poultry litter (PL) relatively to an unfertilized control. Root mass loss was greatest for silphium, owing to low neutral and acid detergent fibers and low lignin contents (6%) relative to the other species (16-25%). Root-C loss was the greatest for Kernza, mostly driven by hemicellulose (soluble sugar) degradation. Poultry litter enhanced root mass loss and C, N, and P mineralization for novel perennial buffer-strip species compared to the control, likely contributing to greater formation of more stable organic matter pool and permanence of root-derived C in soils. Accordingly, SOC stocks were 27-50% greater under silphium-PL after 4 years, owing to higher root sloughing and C inputs to soil. Root decomposition rates were primarily driven by root chemical composition and morphology, while soil CO2 efflux was mostly affected by soil moisture and temperature variations. Greater root decomposition and C mineralization did not increase C-CO2 losses, highlighting the many purposes of novel perennial buffer-strip species –beyond water quality improvement and enhancing C storage and nutrient cycling in agroecosystems. |