Abbreviations: CCAP, container capacity; EWHC, effective water-holding capacity. 1 Assistant Professor. Scientific contribution no. 1381 of the Storm Agricultural Experiment Station. Univ. of Connecticut. This work was supported: in part, with a
Lesley A. Judd, Brian E. Jackson, and William C. Fonteno
volume of substrate in which water, gas, and solute availability can fluctuate over a short period of time ( Polak and Wallach, 2001 ). Physical properties of substrates known to affect roots include AS, container capacity (CC), total porosity (TP
Eugene K. Blythe and Donald J. Merhaut
The physical properties of container-growing substrates, particularly air space, container capacity, and bulk density, have a significant impact on plant growth, and knowledge of these properties is essential in properly managing nursery
Magdalena Zazirska Gabriel, James E. Altland, and James S. Owen Jr
porosity (TP), air space (AS), and container capacity (CC). The most common substrate components use in the Oregon nursery industry is douglas fir [ Pseudotsuga menziesii Mirb. (Franco)] bark (DFB), sphagnum peatmoss, and pumice. Each of these individual
Brian E. Jackson, Robert D. Wright, and Michael C. Barnes
before use as a container substrate; and 3) physical properties such as container capacity (CC) and air space (AS) can be easily altered during the manufacturing process to meet the needs of particular plants and container sizes by the degree of pine wood
James E. Altland, James S. Owen Jr., and Magdalena Z. Gabriel
in pore spaces once filled with air. Container capacity was measured as the volume in water lost from a core that was saturated and drained and then oven dried. Thus CC would include water in the substrate retained in the macro void space after
James S. Owen Jr and James E. Altland
increasing substrate moisture from the top to the bottom of a container. This substrate moisture gradient results in an inverse relationship between air space (AS) and container capacity (CC) where AS decreases and CC increases from the top to the bottom of a
Allyson M. Blodgett, David J. Beattie, John W. White, and George C. Elliott
A plantless system using subirrigation was developed to measure water absorption and loss in soilless media amended with hydrophilic polymers, a wetting agent, or combinations of these amendments. Peat-perlite-vermiculite and bark-peat-perlite controls achieved 67% and 52% of container capacity, respectively, after 20 daily irrigation cycles. Maximum water content of amended media was 78% of container capacity. Adding only a hydrophilic polymer did not increase total water content significantly. Adding a wetting agent increased water absorption in both media. However, when hydrophilic polymer and wetting agent were present, the medium absorbed more water than with wetting agent alone. More extractable water was removed from media containing wetting agent. Water loss rate by evaporation was not affected significantly by medium, hydrophilic polymer, wetting agent, or any combination of these variables.
Carl E. Niedziela Jr. and Paul V. Nelson
A new tube method for determining physical properties in container substrates was compared to an existing system. While both offer the advantages of undisturbed substrate and measurement of properties without altering the geometry of the substrate in the container, the tube method is easier to conduct. Both methods proved equally effective for determining air-tilled porosity, container capacity, total porosity, bulk density, and particle density.
Theo J. Blom and Brian D. Piott
High-volume top irrigation (Chapin) was compared to subirrigation (ebb and flow) using 15-cm-diameter (1.56 liter) pot-grown chrysanthemums [Dendranthema ×grandiflorum (Ramat.) Kitamura] with peatwool (50 peatmoss: 50 granulated rockwool) as the growing substrate. Preplant moisture contents (25%, 125%, and 250%, gravimetric) and compaction (0, 20, and 50 g·cm-2) of the peatwool were also studied. Shrinkage of growing substrate was large (>309'6 of pot volume) when peatwool in the pots was not compacted. Compaction reduced shrinkage and produced plants with larger leaves, more fresh weight, and longer stems than without preplant compaction. Drainable pore space, container capacity, and total porosity was not affected by compaction. The higher preplant moisture contents increased drainable pore space but had no effect on plant growth. Chapin-irrigated plants had significantly more fresh weight (+ 24%) at the pea-size bud stage than plants grown in the ebb-and-flow system. The difference in growth was similar at flowering but significant only at P = 0.08. Soluble salts concentration in the peatwool and foliar nutrient contents differed at flowering for the two irrigation systems.