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

Ippolito, J.A. and Bjorneberg, D.L. and Blecker, S.W. and Massey, M.S. (2019) Mechanisms responsible for soil phosphorus availability differences between sprinkler and furrow irrigation. Journal of Environmental Quality. 27 June 2019.

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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.

Item Type: Article
NWISRL Publication Number: 1653
Subjects: Soil > Chemistry
Soil > Erosion
Soil > Chemistry > Phosphorous
Depositing User: Users 6 not found.
Date Deposited: 09 Jul 2019 15:58
Last Modified: 09 Jul 2019 15:58
Item ID: 1696