Open AccessImpact of Root Growth on the Physical Properties of Peat Substrate under a Constant Water Regimen
Author(s) -
Patrice Cannavo,
Houda Hafdhi,
JeanCharles Michel
Publication year - 2011
Publication title -
hortscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.518
H-Index - 90
eISSN - 2327-9834
pISSN - 0018-5345
DOI - 10.21273/hortsci.46.10.1394
Subject(s) - peat , hydraulic conductivity , porosity , shoot , chemistry , volume (thermodynamics) , tortuosity , bulk density , substrate (aquarium) , soil water , zoology , horticulture , soil science , environmental science , biology , ecology , physics , organic chemistry , quantum mechanics
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 ( θ ) 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.