Long-term conservation tillage breaks the plough pan and promotes the development of preferential flow

Macropores and preferential flow critically regulate soil hydrological functions and ecosystem services in agricultural systems. With the intensification of global soil degradation, especially as conventional tillage (CK) exacerbates soil compaction, conservation tillage (CT) has emerged as a crucia...

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Main Authors: Jinze Han, Jianye Li, Qiang Chen, Xingyi Zhang
Format: Article
Language:English
Published: Elsevier 2025-06-01
Series:Geoderma
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Online Access:http://www.sciencedirect.com/science/article/pii/S0016706125001673
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author Jinze Han
Jianye Li
Qiang Chen
Xingyi Zhang
author_facet Jinze Han
Jianye Li
Qiang Chen
Xingyi Zhang
author_sort Jinze Han
collection DOAJ
description Macropores and preferential flow critically regulate soil hydrological functions and ecosystem services in agricultural systems. With the intensification of global soil degradation, especially as conventional tillage (CK) exacerbates soil compaction, conservation tillage (CT) has emerged as a crucial strategy for restoring soil quality. However, the ability of CT to alleviate soil compaction and regulate macropore structure and preferential flow remains unclear. This study aimed to clarify how long-term CT alleviates compaction-driven constraints on macropore structure and preferential flow in black soil. We selected an 18-year located experimental field on a typical Phaeozem (clay loam, mixed, mesic) in black soil region of Northeast China. X-ray computed tomography (25 μm resolution) and dye tracer techniques (1.5 g L−1 Brilliant Blue solution) were used to quantify macropores and preferential flow paths in 0–50 cm soil layers. Independent samples t-test (assuming equal variances and normal distributions) was used to compare two treatments. Correlation analysis was also performed to assess variable relationships. Path analysis via structural equation modeling to elucidate direct and indirect effects, and CMIN/DF, GFI, RMSEA were used to evaluate model fit. The results revealed that CT effectively alleviated soil compaction by breaking the plough pan and optimizing pore structure. Compared with CK, CT significantly enhanced macroporosity (500–1000 μm) by 4.8 times and pore connectivity by 21.3 times in the critical 10–20 cm layer, while reducing bulk density by 9.4 % and pore tortuosity by 2.1 % in this layer (p < 0.05). Notably, CT generated continuous pore and staining paths extending below 20 cm, thereby alleviating the plough pan barrier. These structural improvements drove preferential flow development, evidenced by a 21.5 % reduction in dye variation coefficient and enhanced soil dye coverage. Correlation analysis showed dye coverage correlated strongly with soil physicochemical properties and macropore indexes, especially 500–1000 μm macroporosity (p < 0.05). Path analysis further confirmed CT governed preferential flow patterns through macroporosity enhancement and pore tortuosity reduction (p < 0.001). This study demonstrates that CT restructures compacted soil into hydraulically active systems through breaking plough pan and improving pore structure, providing mechanistic insights for combating soil degradation in ecologically vulnerable black soil regions.
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spelling doaj-art-ff8e827bbb404a12a3dae71aa0a786f22025-08-20T01:52:55ZengElsevierGeoderma1872-62592025-06-0145811732910.1016/j.geoderma.2025.117329Long-term conservation tillage breaks the plough pan and promotes the development of preferential flowJinze Han0Jianye Li1Qiang Chen2Xingyi Zhang3State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, China; Harbin Normal University, Harbin 150080, China; University of Chinese Academy of Sciences, Beijing 100049, ChinaState Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, China; Corresponding author at: Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, 138 Haping Rd., Harbin 150081, China.Harbin Normal University, Harbin 150080, ChinaState Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, China; University of Chinese Academy of Sciences, Beijing 100049, ChinaMacropores and preferential flow critically regulate soil hydrological functions and ecosystem services in agricultural systems. With the intensification of global soil degradation, especially as conventional tillage (CK) exacerbates soil compaction, conservation tillage (CT) has emerged as a crucial strategy for restoring soil quality. However, the ability of CT to alleviate soil compaction and regulate macropore structure and preferential flow remains unclear. This study aimed to clarify how long-term CT alleviates compaction-driven constraints on macropore structure and preferential flow in black soil. We selected an 18-year located experimental field on a typical Phaeozem (clay loam, mixed, mesic) in black soil region of Northeast China. X-ray computed tomography (25 μm resolution) and dye tracer techniques (1.5 g L−1 Brilliant Blue solution) were used to quantify macropores and preferential flow paths in 0–50 cm soil layers. Independent samples t-test (assuming equal variances and normal distributions) was used to compare two treatments. Correlation analysis was also performed to assess variable relationships. Path analysis via structural equation modeling to elucidate direct and indirect effects, and CMIN/DF, GFI, RMSEA were used to evaluate model fit. The results revealed that CT effectively alleviated soil compaction by breaking the plough pan and optimizing pore structure. Compared with CK, CT significantly enhanced macroporosity (500–1000 μm) by 4.8 times and pore connectivity by 21.3 times in the critical 10–20 cm layer, while reducing bulk density by 9.4 % and pore tortuosity by 2.1 % in this layer (p < 0.05). Notably, CT generated continuous pore and staining paths extending below 20 cm, thereby alleviating the plough pan barrier. These structural improvements drove preferential flow development, evidenced by a 21.5 % reduction in dye variation coefficient and enhanced soil dye coverage. Correlation analysis showed dye coverage correlated strongly with soil physicochemical properties and macropore indexes, especially 500–1000 μm macroporosity (p < 0.05). Path analysis further confirmed CT governed preferential flow patterns through macroporosity enhancement and pore tortuosity reduction (p < 0.001). This study demonstrates that CT restructures compacted soil into hydraulically active systems through breaking plough pan and improving pore structure, providing mechanistic insights for combating soil degradation in ecologically vulnerable black soil regions.http://www.sciencedirect.com/science/article/pii/S0016706125001673No-till with straw mulchingSoil macropore structureX–ray computed tomographyDye coverageBlack soil
spellingShingle Jinze Han
Jianye Li
Qiang Chen
Xingyi Zhang
Long-term conservation tillage breaks the plough pan and promotes the development of preferential flow
Geoderma
No-till with straw mulching
Soil macropore structure
X–ray computed tomography
Dye coverage
Black soil
title Long-term conservation tillage breaks the plough pan and promotes the development of preferential flow
title_full Long-term conservation tillage breaks the plough pan and promotes the development of preferential flow
title_fullStr Long-term conservation tillage breaks the plough pan and promotes the development of preferential flow
title_full_unstemmed Long-term conservation tillage breaks the plough pan and promotes the development of preferential flow
title_short Long-term conservation tillage breaks the plough pan and promotes the development of preferential flow
title_sort long term conservation tillage breaks the plough pan and promotes the development of preferential flow
topic No-till with straw mulching
Soil macropore structure
X–ray computed tomography
Dye coverage
Black soil
url http://www.sciencedirect.com/science/article/pii/S0016706125001673
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AT jianyeli longtermconservationtillagebreakstheploughpanandpromotesthedevelopmentofpreferentialflow
AT qiangchen longtermconservationtillagebreakstheploughpanandpromotesthedevelopmentofpreferentialflow
AT xingyizhang longtermconservationtillagebreakstheploughpanandpromotesthedevelopmentofpreferentialflow