title: Risk of phosphorus leaching from phosphorus-enriched soils in the Dianchi catchment, Southwestern China.
abstract: As an important pathway for phosphorus (P) transport from soil to water body, P leaching has aroused attention. This study aimed to investigate the degree of risk and forms of P leaching from P-enriched soils. Surface soils were collected from forest land (FL) and open agricultural land (OAL) in typical P-enriched area of the Dianchi catchment, China. Based on analysis of soil P and water-soluble P using chemical methods and (31)P-NMR analysis, combined with a soil column leaching experiment, P forms and risk of P leaching were identified. CaCl2-extractable water-soluble organic P (CaCl2-Po), inorganic P (CaCl2-Pi), and total P (CaCl2-P) extracted using 0.01-M CaCl2 solution were found to be useful for predicting potential organic and inorganic P leaching, given a linear, positive correlation between CaCl2-P, CaCl2-Pi, and CaCl2-Po in soils and accumulated amounts of corresponding P forms in soil leachates. The majority of investigated FL was at or above the change points of 46, 46, and 42 mg AP kg(-1) for CaCl2-Pi, CaCl2-Po, and CaCl2-P, respectively, and thus at a risk of P leaching. Organic and inorganic P leaching was present in nearly all investigated OAL. CaCl2-Po accounted for 66.0 % of CaCl2-P in FL and 56.1 % in OAL. Signals of (31)P-NMR spectra were mainly attributable to orthophosphate, orthophosphate monoesters, and orthophosphate diesters in FL and OAL soils. It is important to consider P loss due to leaching of inorganic and organic P in P-enriched areas.
authors.affiliation: College of Resources and Environment, Sino-Danish College, University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.
authors.forename: Meng
authors.initials: M
authors.lastname: Li
authors.forename: Zhengyi
authors.initials: Z
authors.lastname: Hu
authors.forename: Xiaoqi
authors.initials: X
authors.lastname: Zhu
authors.forename: Guohui
authors.initials: G
authors.lastname: Zhou
mesh_terms: D000383:Agriculture; D002681:China; D065928:Forests; D040362:Geographic Information Systems; D009682:Magnetic Resonance Spectroscopy; D008982:Molybdenum; D010316:Particle Size; D010710:Phosphates / Q000032:analysis; D010758:Phosphorus / Q000032:analysis*; D018570:Risk Assessment; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: D010710:Phosphates; D012987:Soil; D012989:Soil Pollutants; D010758:Phosphorus; C017541:molybdenum blue; D008982:Molybdenum