M. Houtermans, E. Lehndorff, S.R. Utami, D. Said-Pullicino, M. Romani, A. Kölbl, K. Kaiser, Z.H. Cao, W. Amelung
Long-term paddy management promotes nitrogen (N) sequestration, but it is unknown to what extent the properties of the parent soil modify the management-induced N sequestration in peptide-bound amino acids (AA-N). We hypothesized that paddy management effects on the storage of AA-N relate to the mineral assembly. Hence, we determined contents and chirality of peptide-bound amino acids in paddy soils developed on contrasting parent material (Vertisols, Andosols, Alisols in Indonesia, Alisols in China, and Gleysol/Fluvisol in Italy). Adjacent non-paddy soils served as references. Selected samples were pre-extracted with dithionite–citrate–bicarbonate (DCB) to better understand the role of reactive oxide phases in AA-N storage, origin, and composition. The results showed that topsoil N and AA-N stocks were significantly larger in paddy-managed Andosols and Chinese Alisols than in their non-paddy counterparts. In other soils, however, paddy management did not cause higher proportions of N and AA-N, possibly because N fixing intercrops masked the paddy management effects on N sequestration processes. Among the different soils developed on contrasting parent material, AA-N stocks were largest in Andosols, followed by Alisols and Fluvisols, and lowest in Vertisols. The N storage in amino acid forms went along with elevated d-contents of bacteria-derived alanine and glutamic acid, as well as with increasing stocks of DCB-extractable Fe, Mn, and Al. Other d-amino acids, likely formed by racemization processes, did not vary systematically between paddy and non-paddy managed soils. Our data suggest that the presence of oxides increase the N sequestration in peptide-bound amino acids after microbial N transformations. © 2017, Springer-Verlag GmbH Germany.
Institute of Crop Science and Resource Conservation (INRES) - Soil Science & Soil Ecology, Bonn University, Nussallee 13, Bonn, 53115, Germany; Faculty of Agriculture, Brawijaya University, Jl. Veteran, Malang, 65145, Indonesia; Soil Biogeochemistry, Department of Agricultural, Forest and Food Sciences, University of Torino, Largo Paolo Braccini 2, Grugliasco, 10095, Italy; Rice Research Centre, Ente Nazionale Risi, Strada per Ceretto 4, Castello d’Agogna, 27030, Italy; Chair for Soil Science, Department Ecology and Ecosystem Management, Technische Universität München, Freising-Weihenstephan, 85350, Germany; Soil Science and Soil Protection, Martin Luther University Halle-Wittenberg, Von-Seckendorff-Platz 3, Halle (Saale), 06120, Germany; The Institute of Soil Science, CAS Chinese Academy of Sciences, Nanjing, 210008, China
