Pedosphere 36(3): 818--829, 2026
ISSN 1002-0160/CN 32-1315/P
©2026 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Macroaggregation positively impacts accumulation of organic nitrogen in an Aquic Inceptisol following straw incorporation |
Xianfeng ZHANG1,3, Guocui REN1,3, Xiuli XIN1,3, Wenliang YANG1,3, Anning ZHU1,2,3 |
1Fengqiu Agro-Ecological Experimental Station, State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 211135 (China);
2 University of Chinese Academy of Sciences, Nanjing, Nanjing 211135 (China);
3 University of Chinese Academy of Sciences, Beijing 100049 (China) |
| ABSTRACT |
| Soil physical fractions (including aggregates and physical subfractions) and organic nitrogen (N) forms have been extensively studied, but the influence of soil N forms in physical fractions on soil organic N accumulation remains unclear. In this study, an arable soil, belonging to an Aquic Inceptisol, was collected from a 5-year continuous straw management experiment to investigate the characteristics of organic N accumulation and its associations with soil aggregates and physical subfractions under contrasting management practices (straw incorporation vs. straw removal). We analyzed soil aggregate distribution, physical subfractions within macro- and microaggregates, and organic N fractions, including hydrolyzable ammonium N (HAN), amino sugar N (ASN), amino acid N (AAN), hydrolyzable unidentified N (HUN), and non-hydrolyzable N (NHN). The concentrations of soil total N and potentially mineralizable N were measured to assess soil N accumulation and availability, respectively. Compared with those under straw removal, the distributions of organic N fractions in bulk soil under straw incorporation were significantly increased: HAN by 50.9%, ASN by 12.6%, AAN by 10.2%, HUN by 57.4%, and NHN by 14.2%. Straw incorporation significantly increased the concentrations of total N and potentially mineralizable N. Path analysis suggested that different organic N fractions contributed variably to soil N accumulation and availability; NHN and HUN contributed the most to soil N accumulation, while HAN and HUN were the primary contributors to soil N availability. From the perspective of soil aggregation, straw incorporation increased the mass of macroaggregates by 11.2%, and macroaggregates exhibited higher accumulation efficiency and greater contributions to organic N fractions compared with microaggregates and the silt + clay fraction. Furthermore, the increase in each organic N fraction, particularly HAN, HUN, and NHN in fine intra-aggregate particulate organic matter, primarily accounted for the enhanced macroaggregate-associated organic N. The findings of this study highlight the positive effects of macroaggregation on N accumulation and availability in the tested Aquic Inceptisol following continuous straw incorporation. |
| Key Words: N accumulation|organic N fraction|physical subfraction|potentially mineralizable N|soil aggregate|soil N availability|straw management practice |
| Citation: Zhang X F, Ren G C, Xin X L, Yang W L, Zhu A N. 2026. Macroaggregation positively impacts accumulation of organic nitrogen in an Aquic Inceptisol following straw incorporation. Pedosphere. 36(3): 818-829. |
|
View Full Text
|
|
|
|
