title: Phosphorus content as a function of soil aggregate size and paddy cultivation in highly weathered soils.
abstract: Red soils are the major land resource in subtropical and tropical areas and are characterized by low phosphorus (P) availability. To assess the availability of P for plants and the potential stability of P in soil, two pairs of subtropical red soil samples from a paddy field and an adjacent uncultivated upland were collected from Hunan Province, China. Analysis of total P and Olsen P and sequential extraction was used to determine the inorganic and organic P fractions in different aggregate size classes. Our results showed that the soil under paddy cultivation had lower proportions of small aggregates and higher proportions of large aggregates than those from the uncultivated upland soil. The portion of >2-mm-sized aggregates increased by 31 and 20 % at Taoyuan and Guiyang, respectively. The total P and Olsen P contents were 50-150 and 50-300 % higher, respectively, in the paddy soil than those in the upland soil. Higher inorganic and organic P fractions tended to be enriched in both the smallest and largest aggregate size classes compared to the middle size class (0.02-0.2 mm). Furthermore, the proportion of P fractions was higher in smaller aggregate sizes (<2 mm) than in the higher aggregate sizes (>2 mm). In conclusion, soils under paddy cultivation displayed improved soil aggregate structure, altered distribution patterns of P fractions in different aggregate size classes, and to some extent had enhanced labile P pools.
authors.affiliation: Changsha Research Station for Agricultural & Environmental Monitoring and Key Laboratory of Agro-ecology Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China.
authors.forename: Baozhen
authors.initials: B
authors.lastname: Li
authors.affiliation: Changsha Research Station for Agricultural & Environmental Monitoring and Key Laboratory of Agro-ecology Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China.
authors.forename: Tida
authors.initials: T
authors.lastname: Ge
authors.affiliation: Changsha Research Station for Agricultural & Environmental Monitoring and Key Laboratory of Agro-ecology Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China.
authors.forename: Heai
authors.initials: H
authors.lastname: Xiao
authors.affiliation: Changsha Research Station for Agricultural & Environmental Monitoring and Key Laboratory of Agro-ecology Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China.
authors.forename: Zhenke
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Changsha Research Station for Agricultural & Environmental Monitoring and Key Laboratory of Agro-ecology Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Li
authors.affiliation: Institute of Soil Science, Leibniz Universität Hannover, 30419, Hannover, Germany.
authors.forename: Olga
authors.initials: O
authors.lastname: Shibistova
authors.affiliation: Changsha Research Station for Agricultural & Environmental Monitoring and Key Laboratory of Agro-ecology Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China.
authors.forename: Shoulong
authors.initials: S
authors.lastname: Liu
authors.affiliation: Changsha Research Station for Agricultural & Environmental Monitoring and Key Laboratory of Agro-ecology Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China. jswu@isa.ac.cn.
authors.forename: Jinshui
authors.initials: J
authors.lastname: Wu
authors.affiliation: Changsha Research Station for Agricultural & Environmental Monitoring and Key Laboratory of Agro-ecology Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China.|Graduate School of Horticulture, Chiba University, Matsudo, 271-8510, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Inubushi
authors.affiliation: Changsha Research Station for Agricultural & Environmental Monitoring and Key Laboratory of Agro-ecology Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China.|Institute of Soil Science, Leibniz Universität Hannover, 30419, Hannover, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Guggenberger
mesh_terms: D000383:Agriculture / Q000379:methods*; D002681:China; D010755:Organophosphates / Q000032:analysis*; D012275:Oryza / Q000254:growth & development*; D010710:Phosphates / Q000032:analysis*; D012987:Soil / Q000737:chemistry* / Q000592:standards; D012989:Soil Pollutants / Q000032:analysis*; D014887:Weather
chemical_list: D010755:Organophosphates; D010710:Phosphates; D012987:Soil; D012989:Soil Pollutants
keywords: Inorganic phosphorus; Organic phosphorus; Paddy cultivation; Soil aggregates