Acceptable physical properties are an integral part of root-media quality. However, there is no one growing medium that works best in all situations because root-media physical properties are not constant, but rather can be affected by the grower. Understanding the root environment under production conditions requires an understanding of the dynamic nature of air : water : solid ratio in the medium. The objective of this review is to consider key aspects of root-medium physical properties, which include bulk density and particle size, container capacity, media settling, water absorption, rewettability, moisture release characteristics, and water loss due to evaporation from the root-medium surface.
William R. Argo
Molly Felts, Renee T. Threlfall, and Margaret L. Worthington
.8 for these genotypes. Texture (flesh hardness, moisture release, awareness of skins, flesh crispness, flesh melting, and fibrousness between teeth) of the fruit was evaluated ( Table 5 ). Panelists detected differences among the genotypes for all
Lucas O’Meara, Matthew R. Chappell, and Marc W. van Iersel
within ultramicropores and is unavailable to plants based on the pressure/tension required to extract such water in a laboratory setting. However, when applied to actual plant material grown in soilless substrates, moisture release theory may not
John A. Biernbaum and Natasha Bos Versluys
Important components of water management for transplant production include water quality, the frequency and volume of water application, and the method of application. Water quality factors of concern are alkalinity, soluble salts including sodium absorption ratio (SAR), and ions at potentially toxic concentrations including boron and fluoride. The available water in individual transplant cells is influence by container size and geometry, medium particle size, medium moisture release characteristics, and wetting agents but is primarily determined by irrigation frequency and the amount of water applied at each irrigation. Irrigation scheduling can be done using several methods but is influenced by the crop stage, the water volume applied, and the frequency of drying desired. Transplants can be watered by hose and breaker, stationary sprinklers, traveling boom sprinklers, fog nozzles, or subirrigation. The outcome of experiments testing effects of transplant size, transplant age and fertilizer rates are all influenced by water management.
F. M. Jeneidi and C. J. Starbuck
The physical characteristics of a container growing medium containing 2 oak sawdust composted with poultry manure: 1 vermiculite: 1 perlite were compared with those of a similar medium containing sphagnum peat rather than compost. Both media were amended with inorganic nutrients based on laboratory analysis to make them nutritionally comparable and with AquaGro wetting agent at 800 g·m–3. Moisture release characteristics of the media were evaluated using tension cups in which desorption at 5, 10, 20, 40, 80, 100, and 160 cm of water was measured. While bulk density of the peat mix (0.129 g·cm–3) was, significantly lower than that of the compost mix (0.157 g·cm–3), total porosity of the peat mix (84%) was significantly greater than that of the compost mix (79%). Air-filled and water-filled porosities of the peat and compost mixes were 18.2% 16.2% and 75.2% 70.5% of container volume, respectively. While the peat mix held more water at tensions between 5 and 20 cm, there was no significant difference between the volumetric water contents of the two media between 20 and 160 cm. Fresh and dry weights of corn plants grown for 3 weeks in compost- and peat-based media were not significantly different.
Yong Ha Rhie and Jongyun Kim
calibration ( Decagon Devices, 2016a , 2016b ). Table 1. Physical and chemical properties of various coir dust and perlite mixes (1:0, 8:2, 6:4, 4:6, 2:8, and 0:1). Moisture release curves are frequently used to predict water availability to plants and for
Molly Felts, Renee T. Threlfall, John R. Clark, and Margaret L. Worthington
was the least metallic, and ‘Ison’ was the most metallic. The panelists evaluated texture (berry hardness, berry crispness, moisture release, awareness of skins, detachability, fibrousness between teeth, and seed separation) for four berries in the
Bruno Casamali, Marc W. van Iersel, and Dario J. Chavez
late-September; and 5) irrigation off from late-September to December. These thresholds were based on soil moisture release curves for the specific soil type at the location. The experimental field was divided in four quadrants, and one soil sample was
Jeb S. Fields, William C. Fonteno, Brian E. Jackson, Joshua L. Heitman, and James S. Owen Jr.
materials holding more residual water. This occurred despite the fact that perlite had a larger percent fine particles than SPW or PWC (PFP; Table 1 ). Fig. 2. Moisture release curves of peat amended with 10%, 20%, 30%, 40%, and 50% perlite, pine wood chips
M. Gabriela Buamscha, James E. Altland, Dan M. Sullivan, Donald A. Horneck, and James Cassidy
compared statistically. Nevertheless, they provide an insight on the moisture-releasing properties of DFB. Container capacity for fresh and aged bark were 36% and 44%, respectively. Easily available water (EAW), the amount of moisture released between 1 and