首页|Fate and availability of dust-borne phosphorus in a sub-humid temperate forest

Fate and availability of dust-borne phosphorus in a sub-humid temperate forest

扫码查看
原文链接
  • NSTL
  • Elsevier
Aeolian dust deposition is an important phosphorus (P) input to terrestrial ecosystems, but it lacks evidence of how dust inputs supply available P and affect P geochemistry and dynamics in soils of sub-humid ecosystems. We determined soil P speciation using P K-edge X-ray absorption near edge spectroscopy and P availability using modified Hedley sequential chemical extractions in a weakly acidic soil profile (2.5 m thick) in a sub-humid temperate forest ecosystem. The soil profile receives substantial dust inputs that account for 34.8% - 53.5% of the soil mass at depths based on a Sr isotope analysis. The acidic topsoils (5 < pH < 5.5) contain Ca-bound P (Ca- P) that accounts for 4%-18% of total soil P. Since Ca-P compounds are unstable and transform to other forms at pH < 5.5, continuous inputs of dust materials rich in Ca-P must occur to sustain the considerable Ca-P in the topsoils. Across all depths, soil Ca-P positively correlates with soil labile Pi (both resin and NaHCO_3 extracted) in proportion, suggesting that dissolution of dust-borne Ca-P compounds replenishes the labile Pi pool. On the other hand, weathering of the Fe-rich dusts leads to formation of abundant iron oxides that in turn favors formation of occluded P (44-85%) and Fe (and Al)-bound P (57-83%), which may fix released P from the dust-borne Ca-P dissolution and reduce soil P availability in a long term. Interestingly, the saprolite layer has an unexpectedly high weathering degree with nearly depleted Ca-P, likely caused by dust inputs that increase soil moisture and microbial activities and accordingly weathering. Our study identifies that continuous deposition and subsequent dissolution of dust-borne Ca-P compounds in acidic soils sustain soil P availability. The study also highlights that aeolian dust inputs affect soil P availability and dynamics in a sub-humid forest ecosystem not only by acting as a bioavailable P source but also altering soil chemistry and weathering.

Phosphorus speciation and availabilityAeolian dust inputsSub-humid temperate forestParticle size fractionsX-ray absorption near edge structurespectroscopy

Zhuojun Zhang、Hairuo Mao、Zhi-Qi Zhao、Shilu Wang、Cong-Qiang Liu、Yongfeng Hu、Mengqiang Zhu

展开 >

State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, Guizhou 550081, China

Department of Ecosystem Science and Management, University of Wyoming, Laramie, WY 82071, United States

School of Earth Science and Resources, Chang'an University, Xi'an, Shaanxi 710054, China

Institute of Surface-Earth System Sciences, Tianjin University, Tianjin 300072, China

Canadian Light Source Inc., University of Saskatchewan, Saskatoon, Saskatchewan S7N 2V3, Canada

展开 >

2022

10.1016/j.chemgeo.2021.120628

Chemical geology

Chemical geology

EISCI
ISSN：0009-2541
年,卷(期)：2022.587
  • 3
  • 90