Straw Incorporation and Nitrogen Fertilization Enhance Soil Organic Carbon Sequestration by Promoting Aggregate Stability and Iron Oxide Transformation

Soil barrenness and a poor stability of organic carbon are important factors restricting sustainable agricultural development. The effects of straw incorporation and nitrogen (N) fertilization on soil aggregates, soil organic carbon (SOC) functional groups, iron (Fe) oxides, and SOC sequestration we...

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Main Authors: Zhichang Jing, Shirong Zhang, Zeqiang Sun, Zhaohui Liu, Shenglin Liu, Xiaodong Ding
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Agronomy
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Online Access:https://www.mdpi.com/2073-4395/15/4/871
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author Zhichang Jing
Shirong Zhang
Zeqiang Sun
Zhaohui Liu
Shenglin Liu
Xiaodong Ding
author_facet Zhichang Jing
Shirong Zhang
Zeqiang Sun
Zhaohui Liu
Shenglin Liu
Xiaodong Ding
author_sort Zhichang Jing
collection DOAJ
description Soil barrenness and a poor stability of organic carbon are important factors restricting sustainable agricultural development. The effects of straw incorporation and nitrogen (N) fertilization on soil aggregates, soil organic carbon (SOC) functional groups, iron (Fe) oxides, and SOC sequestration were evaluated in saline–alkali soil. In this study, we established six treatments involving the combined addition of straw and N in saline–alkali soil in the Yellow River Delta, China, to investigate the changes in SOC. A field experiment was conducted with two N levels (N1, 270 kg N ha<sup>−1</sup>; N2, 210 kg N ha<sup>−1</sup>) and three C treatments (S0, 0 kg ha<sup>−1</sup>; S1, 5000 kg ha<sup>−1</sup>; S2, 10,000 kg ha<sup>−1</sup>). Compared with S0 treatments, straw incorporation and N application significantly increased the proportion of small macro-aggregates, and the mean weight diameter (MWD) was increased by 8.3–18.6%. Under the N2 treatment, with an increase in straw incorporation, the contents of organically complexed Fe oxides (Fep), especially small macro-aggregates and micro-aggregates, increased significantly. Meanwhile, polysaccharides-C and aromatic-C were mainly distributed in small macro-aggregates, forming aromatic Fe complexes with Fep and remaining at the aggregate interface. Compared with the N1S0 treatment, SOC storage increased by 3.94% and 5.12% in the N2S1 and N2S2 treatments, respectively. This could primarily be attributed to an improvement in soil structure, the optimization of OC functional group composition, and the formation of organo-Fe complexes. Straw incorporation and N application were optimal management measures and improved C stability and sequestration capacity. A halved straw incorporation and a reduced N application were the best treatment options for saline–alkali soil.
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spelling doaj-art-5d1a7b212b3446ab88c128bb4b8311652025-08-20T02:24:42ZengMDPI AGAgronomy2073-43952025-03-0115487110.3390/agronomy15040871Straw Incorporation and Nitrogen Fertilization Enhance Soil Organic Carbon Sequestration by Promoting Aggregate Stability and Iron Oxide TransformationZhichang Jing0Shirong Zhang1Zeqiang Sun2Zhaohui Liu3Shenglin Liu4Xiaodong Ding5State Key Laboratory of Nutrient Use and Management, and Key Laboratory of Agro-Environment of Huang-Huai-Hai Plain, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Environment, Shandong Academy of Agricultural Sciences, Jinan 250000, ChinaCollege of Resources and Environment, Qingdao Agricultural University, Qingdao 266109, ChinaState Key Laboratory of Nutrient Use and Management, and Key Laboratory of Agro-Environment of Huang-Huai-Hai Plain, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Environment, Shandong Academy of Agricultural Sciences, Jinan 250000, ChinaState Key Laboratory of Nutrient Use and Management, and Key Laboratory of Agro-Environment of Huang-Huai-Hai Plain, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Environment, Shandong Academy of Agricultural Sciences, Jinan 250000, ChinaState Key Laboratory of Nutrient Use and Management, and Key Laboratory of Agro-Environment of Huang-Huai-Hai Plain, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Environment, Shandong Academy of Agricultural Sciences, Jinan 250000, ChinaCollege of Resources and Environment, Qingdao Agricultural University, Qingdao 266109, ChinaSoil barrenness and a poor stability of organic carbon are important factors restricting sustainable agricultural development. The effects of straw incorporation and nitrogen (N) fertilization on soil aggregates, soil organic carbon (SOC) functional groups, iron (Fe) oxides, and SOC sequestration were evaluated in saline–alkali soil. In this study, we established six treatments involving the combined addition of straw and N in saline–alkali soil in the Yellow River Delta, China, to investigate the changes in SOC. A field experiment was conducted with two N levels (N1, 270 kg N ha<sup>−1</sup>; N2, 210 kg N ha<sup>−1</sup>) and three C treatments (S0, 0 kg ha<sup>−1</sup>; S1, 5000 kg ha<sup>−1</sup>; S2, 10,000 kg ha<sup>−1</sup>). Compared with S0 treatments, straw incorporation and N application significantly increased the proportion of small macro-aggregates, and the mean weight diameter (MWD) was increased by 8.3–18.6%. Under the N2 treatment, with an increase in straw incorporation, the contents of organically complexed Fe oxides (Fep), especially small macro-aggregates and micro-aggregates, increased significantly. Meanwhile, polysaccharides-C and aromatic-C were mainly distributed in small macro-aggregates, forming aromatic Fe complexes with Fep and remaining at the aggregate interface. Compared with the N1S0 treatment, SOC storage increased by 3.94% and 5.12% in the N2S1 and N2S2 treatments, respectively. This could primarily be attributed to an improvement in soil structure, the optimization of OC functional group composition, and the formation of organo-Fe complexes. Straw incorporation and N application were optimal management measures and improved C stability and sequestration capacity. A halved straw incorporation and a reduced N application were the best treatment options for saline–alkali soil.https://www.mdpi.com/2073-4395/15/4/871soil aggregate stabilityorganic carbon componentorganic–Fe complexescarbon sequestrationsaline–alkaline soil
spellingShingle Zhichang Jing
Shirong Zhang
Zeqiang Sun
Zhaohui Liu
Shenglin Liu
Xiaodong Ding
Straw Incorporation and Nitrogen Fertilization Enhance Soil Organic Carbon Sequestration by Promoting Aggregate Stability and Iron Oxide Transformation
Agronomy
soil aggregate stability
organic carbon component
organic–Fe complexes
carbon sequestration
saline–alkaline soil
title Straw Incorporation and Nitrogen Fertilization Enhance Soil Organic Carbon Sequestration by Promoting Aggregate Stability and Iron Oxide Transformation
title_full Straw Incorporation and Nitrogen Fertilization Enhance Soil Organic Carbon Sequestration by Promoting Aggregate Stability and Iron Oxide Transformation
title_fullStr Straw Incorporation and Nitrogen Fertilization Enhance Soil Organic Carbon Sequestration by Promoting Aggregate Stability and Iron Oxide Transformation
title_full_unstemmed Straw Incorporation and Nitrogen Fertilization Enhance Soil Organic Carbon Sequestration by Promoting Aggregate Stability and Iron Oxide Transformation
title_short Straw Incorporation and Nitrogen Fertilization Enhance Soil Organic Carbon Sequestration by Promoting Aggregate Stability and Iron Oxide Transformation
title_sort straw incorporation and nitrogen fertilization enhance soil organic carbon sequestration by promoting aggregate stability and iron oxide transformation
topic soil aggregate stability
organic carbon component
organic–Fe complexes
carbon sequestration
saline–alkaline soil
url https://www.mdpi.com/2073-4395/15/4/871
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