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| Effects and mechanisms of straw and its carbonization incorporation on paddy soil aggregate formation, carbon sequestration and nutrient supply capacity in northeast China |
| Received:December 28, 2024 |
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| KeyWord:straw incorporation;biochar;soil aggregates;organic carbon fractions;soil fertility |
| Author Name | Affiliation | E-mail | | GU Wenqi | Liaoning Biochar Engineering & Technology Research Center, Agronomy College, Shenyang Agricultural University, Shenyang 110866, China | | | SUN Yuanyuan | Liaoning Biochar Engineering & Technology Research Center, Agronomy College, Shenyang Agricultural University, Shenyang 110866, China | | | WU Di | Liaoning Biochar Engineering & Technology Research Center, Agronomy College, Shenyang Agricultural University, Shenyang 110866, China | | | SUN Wen | Liaoning Biochar Engineering & Technology Research Center, Agronomy College, Shenyang Agricultural University, Shenyang 110866, China | | | WANG Xin | Liaoning Biochar Engineering & Technology Research Center, Agronomy College, Shenyang Agricultural University, Shenyang 110866, China | | | LIU Zifan | Liaoning Biochar Engineering & Technology Research Center, Agronomy College, Shenyang Agricultural University, Shenyang 110866, China | | | WANG Wenjia | Liaoning Biochar Engineering & Technology Research Center, Agronomy College, Shenyang Agricultural University, Shenyang 110866, China | | | ZHANG Weiming | Liaoning Biochar Engineering & Technology Research Center, Agronomy College, Shenyang Agricultural University, Shenyang 110866, China | biochar_zwm@syau.edu.cn | | CHEN Wenfu | Liaoning Biochar Engineering & Technology Research Center, Agronomy College, Shenyang Agricultural University, Shenyang 110866, China | wfchen5512@126.com |
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| Abstract: |
| To investigate the impacts of straw incorporation and its carbonization on paddy soil aggregate formation, stability, carbon sequestration, and nutrient-supplying capacity in northeast China, we established a long-term field experiment comparing chemical fertilizer（CF）, rice straw（RS）, rice straw biochar（RB）, and biochar-based fertilizer（BF）treatments. We examined aggregate distribution and stability, nutrient content, organic carbon fractions, and carbon conversion-related enzyme activities. The results revealed that straw incorporation and its carbonization significantly enhanced macroaggregate formation, with RB, RS, and BF treatments increasing macroaggregates by 40.83%, 37.78%, and 24.97%, respectively, compared to CF, while substantially improving aggregate stability. Notably, the intensity of —OH, —CH3, and C—O—C absorption peaks in macroaggregates increased, facilitating macroaggregate formation and stabilization. Meanwhile, the treatments enhanced soil organic carbon（SOC）content and altered its fractions, synergistically increasing both soil reactive organic carbon（particulate organic carbon（POC）, light fraction organic carbon（LFOC））and inert organic carbon （mineral-associated carbon（MAOC）, heavy fraction organic carbon（HFOC））. RS treatment exhibited significant enhancement of POC, whereas RB demonstrated superior performance in elevating LFOC, HFOC, and MAOC compared to other treatments. Additionally, Synergistic enhancement of β-1, 4-glucanase（S-C1）, polyphenol oxidase（S-PPO）and peroxidase（S-POD）by RB, S-C1 and S-POD by BF, and S-PPO by RS in soil and macroaggregates, facilitating soil carbon sequestration and transformation. The treatments also demonstrated positive effects on nitrogen, phosphorus, and potassium content, with macroaggregates serving as primary nutrient repositories. Further analysis showed that LFOC and S-PPO emerged as primary factors influencing soil aggregate size distribution, while treatment differences were predominantly driven by SOC, HFOC, S-PPO, S-C1, and total potassium（TK）. MAOC and HFOC could directly drive soil macroaggregate formation. Whereas, soil nutrients, soil enzymes, and different carbon fractions could improve soil aggregate stability through direct and indirect pathways. Research indicates that straw and its carbonization incorporation can enhance soil carbon sequestration and nutrient supply capacities in northern paddy soils by regulating soil nutrients, SOC and its fractions, and carbon transformation-related enzyme activities. This promotes macroaggregate formation and improves aggregate stability. |
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