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Impact of root growth on the physical properties of peat substrate under a constant water regimen

Abstract : The impact of root growth on the hydraulic properties of peat substrate was investigated under optimal water retention, i.e., at a constant water potential of -1 kPa. 'New Guinea' impatiens was grown in 1.1-L cylindrical containers for 196 d in a greenhouse under controlled climate and fertilization conditions. Water retention and hydraulic conductivity curves, root biomass and volume, and shoot weight were measured. Results indicated a maximal root volumetric content of 0.065 m(3).m(-3) that was as high as the peat content in containers (0.068 m(3)-m(-3)). From Day 0 to Day 196, the total porosity of the growing media decreased from 0.931 m(3).m(-3) to 0.874 m(3).m(-3). Moreover, considering the water-holding capacity at a water potential of-1 kPa, it increased from 0.58 to 0.75 m(3).m(-3) (i.e., by 29.3%) without changes in water availability but with a large decrease in air-filled porosity from 0.35 to 0.14 m(3).m(-3). The unsaturated hydraulic conductivity K(theta) decreased as a result of root growth. Root growth also modified pore size distribution and pore structure. Hydraulic conductivity curves indicated a better pore connectivity reflected by a decrease in tortuosity.
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Submitted on : Friday, September 7, 2012 - 3:31:10 PM
Last modification on : Monday, July 6, 2020 - 3:38:28 PM


  • HAL Id : hal-00729278, version 1


Patrice Cannavo, H. Hafdhi, J. C. Michel. Impact of root growth on the physical properties of peat substrate under a constant water regimen. HortScience, American Society for Horticultural Science, 2011, 46 (10), pp.1394-1399. ⟨hal-00729278⟩



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