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Soil strength influences wheat root interactions with soil macropores
Author(s) -
Atkinson Jonathan A.,
Hawkesford Malcolm J.,
Whalley William R.,
Zhou Hu,
Mooney Sacha J.
Publication year - 2020
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.13659
Subject(s) - macropore , subsoil , soil structure , soil science , bulk soil , environmental science , agronomy , compaction , characterisation of pore space in soil , rhizosphere , soil water , bulk density , porosity , chemistry , soil organic matter , geology , biology , geotechnical engineering , bacteria , mesoporous material , paleontology , biochemistry , catalysis
Abstract Deep rooting is critical for access to water and nutrients found in subsoil. However, damage to soil structure and the natural increase in soil strength with depth, often impedes root penetration. Evidence suggests that roots use macropores (soil cavities greater than 75 μm) to bypass strong soil layers. If roots have to exploit structures, a key trait conferring deep rooting will be the ability to locate existing pore networks; a trait called trematotropism. In this study, artificial macropores were created in repacked soil columns at bulk densities of 1.6 g cm −3 and 1.2 g cm −3 , representing compact and loose soil. Near isogenic lines of wheat, Rht‐B1a and Rht‐B1c, were planted and root–macropore interactions were visualized and quantified using X‐ray computed tomography. In compact soil, 68.8% of root–macropore interactions resulted in pore colonization, compared with 12.5% in loose soil. Changes in root growth trajectory following pore interaction were also quantified, with 21.0% of roots changing direction (±3°) in loose soil compared with 76.0% in compact soil. These results indicate that colonization of macropores is an important strategy of wheat roots in compacted subsoil. Management practices to reduce subsoil compaction and encourage macropore formation could offer significant advantage in helping wheat roots penetrate deeper into subsoil.