Abstract
The determination of air and water holding capacities of horticultural substrates has been plagued by errors in measurement. The amount of air and water held at container capacity is influenced by the substrate and container height. Container capacity can be established through specific measurement. Air space, the difference between total porosity and container capacity, is usually poorly determined because of errors in total porosity measurement. Most researchers calculate total porosity (St) from the formula: St = 1-(ρb/ρp), where ρb is the dry bulk density and ρp is the particle density. While bulk density is usually measured, particle density is not. Many times an average ρp of 2.65 Mg·m-3 for mineral soils is used. This sometimes creates large errors in calculating total porosity because the values of ρp for horticultural substrates range from 0.35 to 2.1 Mg·m-3. Total porosity can be measured with great accuracy at 0 kPa tension on a pressure plate apparatus, but is costly in equipment and time. Using a modified method of extraction and a new apparatus, using standard aluminum soil sampling cylinders, total porosity was measured with an 85% reduction in time end no decrease in accuracy.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
