Plant exudates improve the mechanical conditions for root penetration through compacted soils

E. Oleghe, Muhammad Naveed, E.M. Baggs, P.D. Hallett

Research output: Contribution to journalArticle

Abstract

Background and aim
Plant exudates greatly affect the physical behaviour of soil, but measurements of the impact of exudates on compression characteristics are missing. Our aim is to provide these data and explore how plant exudates may enhance the restructuring of compacted soils following cycles of wetting and drying.

Methods
Two soils were amended with Chia (Salvia hispanica) seed exudate at 5 concentrations, compacted in cores to 200 kPa stress (equivalent to tractor stress), equilibrated to −50 kPa matric potential, and then compacted to 600 kPa (equivalent to axial root stress) followed by 3 cycles of wetting and drying and recompression to 600 kPa at −50 kPa matric potential. Penetration resistance (PR), compression index (CC) and pore characteristics were measured at various steps.

Results
PR decreased and CC increased with increasing exudate concentration. At 600 kPa compression, 1.85 mg exudate g−1 soil increased CC from 0.37 to 0.43 for sandy loam soil and from 0.50 to 0.54 for clay loam soil. After 3 wetting-drying cycles the clay loam was more resillient than the sandy loam soil, with resilience increasing with greater exudate concentration. Root growth modelled on PR data suggested plant exudates significantly eased root elongation in soil.

Conclusion
Plant exudates improve compression characteristics of soils, easing penetration and enhancing recovery of root induced soil compaction.
Original languageEnglish
Pages (from-to)19-30
JournalPlant and Soil
Volume421
Issue number1-2
Early online date25 Sep 2017
DOIs
Publication statusE-pub ahead of print - 25 Sep 2017
Externally publishedYes

Fingerprint

plant exudates
compacted soils
penetration
resistance to penetration
drying
soil
compression
sandy loam soils
matric potential
root growth
clay loam
Salvia hispanica
sandy loam
wetting
clay loam soils
soil compaction
tractors
wetting-drying cycle
clay
seeds

Cite this

Oleghe, E. ; Naveed, Muhammad ; Baggs, E.M. ; Hallett, P.D. . / Plant exudates improve the mechanical conditions for root penetration through compacted soils. In: Plant and Soil. 2017 ; Vol. 421, No. 1-2. pp. 19-30.
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abstract = "Background and aimPlant exudates greatly affect the physical behaviour of soil, but measurements of the impact of exudates on compression characteristics are missing. Our aim is to provide these data and explore how plant exudates may enhance the restructuring of compacted soils following cycles of wetting and drying.MethodsTwo soils were amended with Chia (Salvia hispanica) seed exudate at 5 concentrations, compacted in cores to 200 kPa stress (equivalent to tractor stress), equilibrated to −50 kPa matric potential, and then compacted to 600 kPa (equivalent to axial root stress) followed by 3 cycles of wetting and drying and recompression to 600 kPa at −50 kPa matric potential. Penetration resistance (PR), compression index (CC) and pore characteristics were measured at various steps.ResultsPR decreased and CC increased with increasing exudate concentration. At 600 kPa compression, 1.85 mg exudate g−1 soil increased CC from 0.37 to 0.43 for sandy loam soil and from 0.50 to 0.54 for clay loam soil. After 3 wetting-drying cycles the clay loam was more resillient than the sandy loam soil, with resilience increasing with greater exudate concentration. Root growth modelled on PR data suggested plant exudates significantly eased root elongation in soil.ConclusionPlant exudates improve compression characteristics of soils, easing penetration and enhancing recovery of root induced soil compaction.",
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Plant exudates improve the mechanical conditions for root penetration through compacted soils. / Oleghe, E. ; Naveed, Muhammad; Baggs, E.M. ; Hallett, P.D. .

In: Plant and Soil, Vol. 421, No. 1-2, 25.09.2017, p. 19-30.

Research output: Contribution to journalArticle

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N2 - Background and aimPlant exudates greatly affect the physical behaviour of soil, but measurements of the impact of exudates on compression characteristics are missing. Our aim is to provide these data and explore how plant exudates may enhance the restructuring of compacted soils following cycles of wetting and drying.MethodsTwo soils were amended with Chia (Salvia hispanica) seed exudate at 5 concentrations, compacted in cores to 200 kPa stress (equivalent to tractor stress), equilibrated to −50 kPa matric potential, and then compacted to 600 kPa (equivalent to axial root stress) followed by 3 cycles of wetting and drying and recompression to 600 kPa at −50 kPa matric potential. Penetration resistance (PR), compression index (CC) and pore characteristics were measured at various steps.ResultsPR decreased and CC increased with increasing exudate concentration. At 600 kPa compression, 1.85 mg exudate g−1 soil increased CC from 0.37 to 0.43 for sandy loam soil and from 0.50 to 0.54 for clay loam soil. After 3 wetting-drying cycles the clay loam was more resillient than the sandy loam soil, with resilience increasing with greater exudate concentration. Root growth modelled on PR data suggested plant exudates significantly eased root elongation in soil.ConclusionPlant exudates improve compression characteristics of soils, easing penetration and enhancing recovery of root induced soil compaction.

AB - Background and aimPlant exudates greatly affect the physical behaviour of soil, but measurements of the impact of exudates on compression characteristics are missing. Our aim is to provide these data and explore how plant exudates may enhance the restructuring of compacted soils following cycles of wetting and drying.MethodsTwo soils were amended with Chia (Salvia hispanica) seed exudate at 5 concentrations, compacted in cores to 200 kPa stress (equivalent to tractor stress), equilibrated to −50 kPa matric potential, and then compacted to 600 kPa (equivalent to axial root stress) followed by 3 cycles of wetting and drying and recompression to 600 kPa at −50 kPa matric potential. Penetration resistance (PR), compression index (CC) and pore characteristics were measured at various steps.ResultsPR decreased and CC increased with increasing exudate concentration. At 600 kPa compression, 1.85 mg exudate g−1 soil increased CC from 0.37 to 0.43 for sandy loam soil and from 0.50 to 0.54 for clay loam soil. After 3 wetting-drying cycles the clay loam was more resillient than the sandy loam soil, with resilience increasing with greater exudate concentration. Root growth modelled on PR data suggested plant exudates significantly eased root elongation in soil.ConclusionPlant exudates improve compression characteristics of soils, easing penetration and enhancing recovery of root induced soil compaction.

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