Pedosphere 34(6): 1086--1099, 2024
ISSN 1002-0160/CN 32-1315/P
©2024 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Increased humic materials explain aggregate-protected carbon and nitrogen accumulation in biochar-amended tropical soils |
Emmanuel AMOAKWAH1,2 , Mohammad A. RAHMAN2, Khandakar R. ISLAM2, Kwame A. FRIMPONG3, Christian A. PHARES3, Louis SACKEY1, Isaac ASIRIFI4, Emmanuel ARTHUR5 |
1 Council for Scientific and Industrial Research-Soil Research Institute, Accra Center, Post Office Box M 32, Accra GA-018-2527 (Ghana);
2 Soil, Water and Bioenergy Resources, The Ohio State University South Centers, Piketon OH 45661 (USA);
3 Department of Soil Science, College of Agriculture and Natural Sciences, School of Agriculture, University of Cape Coast, Private Mail Bag, Cape Coast CC-145-8669 (Ghana);
4 Ruhr-Universit?t Bochum, Geographic Institute, Department of Soil Science and Soil Ecology, Bochum 44780 (Germany);
5 Department of Agroecology, Faculty of Technical Sciences, Arhus University, Blichers Allé 20, Postbox 50, Tjele DK-8830 (Denmark) |
| Corresponding Author:Emmanuel AMOAKWAH |
| ABSTRACT |
| Humic materials make important contributions to soil organic carbon (C) and nitrogen (N) accumulation. However, information on the correlation between humic substances and the accumulation of soil aggregate-protected C and N in response to biochar application under tropical agroecosystems is limited. Therefore, a field trial was conducted to elucidate the effects of biochar on soil aggregate properties and humic materials and how these humic compounds affect aggregate-protected C and N in a humid tropical agroecosystem. The treatments included no-biochar control (CK), 15 Mg biochar ha-1 (BC-15), 30 Mg biochar ha-1 (BC-30), and 30 Mg biochar ha-1+ phosphate fertilizer (BC-30+P). The treatments BC-30 and BC-30+P significantly increased the contents of humic materials (humic and fulvic acids) as compared to CK. There was a significant increase in the mean-weight diameter of soil aggregates by 3- and 4-fold in BC-30 and BC-30+P, respectively. Similarly, BC-30 and BC-30+P led to significant increases in soil structural coefficient by 3- and 4-fold, respectively, relative to CK. Significant increases in organic C and N accumulation were observed in the macroaggregates of the biochar-amended soils. Inverse relationships between the degree of polymerization and aggregate-protected C and N were observed, implying that low-molecular-weight aliphatic compounds favor organic C and N accumulation with biochar amendments. The important soil property that contributed to organic C and N accumulation in aggregates was fulvic acid content, which could be used as an early and sensitive indicator to notice early changes in aggregate-protected C and N accumulation in soils of the humid tropics. |
| Key Words: degree of humification,fulvic acid,humic acid,macroaggregates,soil structural coefficient |
| Citation: Amoakwah E, Rahman M A, Islam K R, Frimpong K A, Phares C A, Sackey L, Asirifi I, Arthur E. 2024. Increased humic materials explain aggregate-protected carbon and nitrogen accumulation in biochar-amended tropical soils. Pedosphere. 34(6): 1086-1099. |
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