[CC; which is the equivalent to the waterholding capacity (WHC) of a substrate] during crop production so that growing conditions remain favorable for plant growth. Physical properties of substrates considered appropriate for plant growth at planting
as a result of their manufacturing process and physical properties) and were derived from a mixture of various tree species, primarily spruce ( Picea abies L.). Jackson and Wright (2008) and Jackson et al. (2008) report no significant visual
most common base medium for soilless substrates; peatmoss has great physical and chemical buffering properties for soilless substrates due to its high cation-exchange and water-holding capacities, good aeration, and resistance to decomposition ( Fonteno
drainage and aeration in peat-based substrates. More recently, Buck and Evans (2010) revealed that given its physical properties, ground PBH can be used as a suitable replacement for up to 40% peatmoss to grow greenhouse crops. A preferred container
of the research conducted on the physical properties of biocontainers has been focused on short-term crops such as annual bedding plants grown using overhead irrigation systems. However, many greenhouse crops are grown as potted florist crops that
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.
Abstract
This paper describes a system for predicting container mixture physical and chemical properties from component properties. An additive model is presented that assumes that a mixture property is the weighted sum of the properties contributed by the individual components. To test this hypothesis, 24 combinations of sandy loam soil (Typic Xerothent), sand (Typic Xeropsamment), bark, and perlite were tested for bulk density, total and air-filled porosities, container capacity, available water, saturated hydraulic conductivity, pH, and cation exchange capacity. The measured experimental data were compared with values predicted from the additive model. Measured and predicted values were in good agreement for most properties, except saturated hydraulic conductivity and air-filled porosity for mixtures with low total porosity. Application of the same approach also worked well for previously published data.
physical properties of soil in different forms and several studies have shown these benefits ( Demir and Işık, 2020 ; Rós and Hirata, 2019 ; Soares et al., 2021 ). Although cassava is known worldwide for its rusticity and low nutritional requirements
Abstract
Physical properties of various hardwood bark-soil mixes for containers were compared to a soil-peat-perlite mix. Bark-soil mixes containing a wide range of bark particle sizes were found to possess superior physical properties initially and remained satisfactory after a 13-month incubation period. However, bark-soil mixes were much less stable and deteriorated to a significantly greater extent. For golf greens, physical properties of hardwood bark or peat and soil and sand mixes were studied following compaction at 40 cm moisture tension. Initially, the bark mixes were superior and this was postulated to be due to a more uniform distribution of bark within the mixes. Based on the deterioration that occurred in bark-soil mixes for containers, it is concluded that use of hardwood bark in golf green mixes does not appear feasible.
Selected physical properties of 13 coconut coir dusts from Asia, America, and Africa were compared to physical properties of sphagnum peat. All properties studied differed significantly between and within sources, and from the peat. Coir dusts from India, Sri Lanka, and Thailand were composed mainly of pithy tissue, whereas most of those from Costa Rica, Ivory Coast, and Mexico contained abundant fiber which was reflected by a higher coarseness index (percentage by weight of particles larger than 1 mm in diameter). Coir dust was evaluated as a lightweight material, and its total porosity was above 94% (by volume). It also exhibited a high air content (from 24% to 89% by volume) but a low easily available and total water-holding capacity which ranged from <1% to 36% by volume and from 137 to 786 mL·L–1, respectively. Physical properties of coir dust were strongly dependent on particle size distribution. Both easily available and total water-holding capacity declined proportionally with increasing coarseness index, while air content was positively correlated. Relative hydraulic conductivity in the range of 0 to 10 kPa suction dropped as particle size increased. Coir dusts with a particle size distribution similar to peat showed comparatively higher aeration and lower capacity to hold total and easily available water. An air–water balance similar to that in peat became apparent in coir dust at a comparatively lower coarseness index (29% vs. 63% by weight in peat). Stepwise multiple regression analysis showed that particles with diameters in the range of 0.125 to 1 mm had a remarkable and highly significant impact on the physical properties studied, while particles <0.125 mm and >1 mm had only a slight or nonsignificant effect.