TY - JOUR
T1 - Intensive agricultural management-induced subsurface accumulation of labile phosphorus in Midwestern agricultural soils dominated by tile lines
AU - Xu, Suwei
AU - Gentry, Lowell
AU - Chen, Kai Yue
AU - Arai, Yuji
N1 - Funding Information:
The authors gratefully acknowledge Illinois Nutrient Research and Education Council (#2016‐4‐360347‐203) and the United States Department of Agriculture (# 2016‐67019‐25268) for supporting this project financially. Use of the Stanford Synchrotron Radiation Laboratory, Stanford Linear Accelerator Center National Accelerator Laboratory, is supported by the USDOE, Office of Science, Office of Basic Energy Sciences under Contract No. DE‐AC02‐76SF00515.
Publisher Copyright:
© 2020 The Authors. Soil Science Society of America published by Wiley Periodicals LLC on behalf of Soil Science Society of America
PY - 2020/7/1
Y1 - 2020/7/1
N2 - In addition to surface runoff, subsurface P loss through tile lines in agricultural lands has received attention over the last decade. It is not clearly understood how this strong ligand, phosphate, is distributed in subsoils (≤180 cm), contributing to subsurface P loss. We hypothesized that subsurface accumulation of labile P as a result of long-term intensive agricultural management contributes to subsurface P loss. The depth sequence distribution of P and its speciation and reactivity were investigated in tile-line-dominated Midwestern agricultural fields via chemical extraction and digestion, batch desorption experiments, and X-ray absorption near-edge structure spectroscopy. The results suggest that labile P in subsoils exceeds the eutrophication-inducing level (>0.01 mg L–1). Because of intensive agricultural management, total P was ∼400 mg kg–1 in surface soils and ∼200-300 mg kg–1 in subsoils. The depth sequence distribution of P indicated the translocation of P to subsoils. Although phosphate and phytic acid adsorbed by Al or Fe (oxyhydro)oxides and calcite were found in surface soils, phosphate adsorbed to calcite, hydroxyapatite, or both were the dominant P species in subsoils. Phosphate was highest in surface soils and decreased sharply with increasing depth. Slightly alkaline soil in subsoils suppressed the release of P but the process was continuous after 30 d. Subsurface P loss was influenced by the dissolution and desorption process of inorganic P phases and preferentially transported P from surface soils. Subsurface P loss should be considered in strategies to reduce agricultural P loss in the Gulf of Mexico.
AB - In addition to surface runoff, subsurface P loss through tile lines in agricultural lands has received attention over the last decade. It is not clearly understood how this strong ligand, phosphate, is distributed in subsoils (≤180 cm), contributing to subsurface P loss. We hypothesized that subsurface accumulation of labile P as a result of long-term intensive agricultural management contributes to subsurface P loss. The depth sequence distribution of P and its speciation and reactivity were investigated in tile-line-dominated Midwestern agricultural fields via chemical extraction and digestion, batch desorption experiments, and X-ray absorption near-edge structure spectroscopy. The results suggest that labile P in subsoils exceeds the eutrophication-inducing level (>0.01 mg L–1). Because of intensive agricultural management, total P was ∼400 mg kg–1 in surface soils and ∼200-300 mg kg–1 in subsoils. The depth sequence distribution of P indicated the translocation of P to subsoils. Although phosphate and phytic acid adsorbed by Al or Fe (oxyhydro)oxides and calcite were found in surface soils, phosphate adsorbed to calcite, hydroxyapatite, or both were the dominant P species in subsoils. Phosphate was highest in surface soils and decreased sharply with increasing depth. Slightly alkaline soil in subsoils suppressed the release of P but the process was continuous after 30 d. Subsurface P loss was influenced by the dissolution and desorption process of inorganic P phases and preferentially transported P from surface soils. Subsurface P loss should be considered in strategies to reduce agricultural P loss in the Gulf of Mexico.
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U2 - 10.1002/saj2.20089
DO - 10.1002/saj2.20089
M3 - Article
AN - SCOPUS:85089103091
SN - 0361-5995
VL - 84
SP - 1094
EP - 1109
JO - Soil Science Society of America Journal
JF - Soil Science Society of America Journal
IS - 4
ER -