Mechanisms Responsible for Soil Phosphorus Availability Differences between Sprinkler and Furrow Irrigation

Journal Article · Thu Jun 27 00:00:00 EDT 2019 · Journal of Environmental Quality

DOI:https://doi.org/10.2134/jeq2019.01.0016· OSTI ID:1599929

Ippolito, James A. ^[1]; Bjorneberg, Dave L. ^[2]; Blecker, Steve W. ^[3]; Massey, Michael S. ^[4]

---

1. Dep. of Soil and Crop Sciences, C127 Plant Sciences Building Colorado State Univ. Fort Collins CO 80523‐1170
2. USDA‐ARS Northwest Irrigation and Soils Research Lab. 3793N, 3600E Kimberly ID 83341
3. California Dep. of Food and Agriculture Office of Pesticide Consultation &, Analysis 2800 Gateway Oaks Dr. Sacramento CA 95833
4. Dep. of Earth and Environmental Sciences California State Univ. East Bay 25800 Carlos Bee Blvd. Hayward CA 94542

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 ⁻¹ of Olsen‐extractable P (i.e., plant‐available P), respectively; extractable P values over 40 mg kg ⁻¹ 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 Fe‐associated 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. Core Ideas Irrigation type may greatly affect soil P dynamics in calcareous systems. Furrow irrigated fields contained more plant‐available P than sprinkler irrigated fields. Furrow irrigation leads to Fe chemistry alterations, release of P, and increases available P. Available P increases under furrow irrigation could limit amendment application based on P, not N, crop needs. We still do not fully understand P dynamics in irrigated calcareous systems.

• Sponsoring Organization: USDOE
• OSTI ID: 1599929
• Alternate ID(s): OSTI ID: 1787369
• Journal Information: Journal of Environmental Quality, Journal Name: Journal of Environmental Quality Vol. 48 Journal Issue: 5; ISSN 0047-2425
• Publisher: Wiley Blackwell (John Wiley & Sons)
• Country of Publication: United States
• Language: English