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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #365820
Research Project: Improving Water Use Efficiency and Water Quality in Irrigated Agricultural Systems

Location: Northwest Irrigation and Soils Research

Title: Mechanisms responsible for soil phosphorus availability differences between sprinkler and furrow irrigation

Author
item IPPOLITO, JAMES - Colorado State University
item Bjorneberg, David - Dave
item BLECKER, STEVE - California Department Of Food And Agriculture
item MASSEY, MICHAEL - California State University

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/14/2019
Publication Date: 6/27/2019
Citation: Ippolito, J.A., Bjorneberg, D.L., Blecker, S.W., Massey, M.S. 2019. Mechanisms responsible for soil phosphorus availability differences between sprinkler and furrow irrigation. Journal of Environmental Quality. 48:1-10. https://doi.org/10.2134/jeq2019.01.0016.
DOI: https://doi.org/10.2134/jeq2019.01.0016

Interpretive Summary: Converting fields from furrow irrigation to sprinkler irrigation will decrease erosion and associated phosphorus loss. Our study goal was to determine the characteristics of soil phosphorus in furrow irrigated fields (in place since the early 1900s) compared to sprinkler irrigated field that were furrow irrigated within the last ten years. Results indicate that changes in phosphorus forms occur slowly over time, as few differences were observed after three years of sprinkler irrigation. Overall findings suggest that iron chemistry or changes in calcium-associated P in flooded conditions altered phosphorus availability under furrow irrigation.

Technical Abstract: From a historical perspective, human-induced soil erosion and resulting soil phosphorus (P) losses have likely occurred for thousands of years. In modern times, erosion risk and off-site P transport can be decreased if producers convert from furrow to sprinkler irrigation, but conversion may alter nutrient dynamics. Our study goal was to determine soil P dynamics in furrow- (in place since the early 1900s) versus sprinkler-irrigated (installed within the last decade) soils from four paired producer fields in Idaho. Furrow- and sprinkler-irrigated soils (0–5 cm; Aridisols) contained on average 38 and 20 mg/kg of Olsen-extractable P (i.e., plant-available P), respectively; extractable P values over 40 mg/kg limit Idaho producers to P application based on crop uptake only. Soil samples were also analyzed using a modified Hedley extraction. Furrow-irrigated soils contained greater inorganic P concentrations in the soluble+aluminum (Al)-bound+iron (Fe)-bound, occluded, and amorphous Fe bound pools. Phosphorus K-edge X-ray absorption near-edge structure (XANES) spectroscopy was unable to detect Feassociated P but indicated greater amounts of apatite-like or octacalcium phosphate-like P in furrow-irrigated producer soils, while sprinkler-irrigated fields had lower amounts of apatite-like P and greater proportions of P bound to calcite. Findings from a controlled USDA-ARS sprinkler- versus furrow-irrigation study suggested that changes in P dynamics occur slowly over time, as few differences were observed. Overall findings suggest that Fe redox chemistry or changes in calcium (Ca)-associated P in flooded conditions altered P availability under furrow irrigation, even in aridic, calcareous soils, contributing to greater Olsen extractable P concentrations in long-term furrow-irrigated fields.