Articles
Identifying native bulk density for static physical properties analysis
Article number
1409_17
Pages
121 – 124
Language
English
Abstract
Soilless substrate rings are commonly prepared in the laboratory rather than sampling in situ.
Rings are packed by filling with loose substrate before being tapped on the benchtop; however, this method can yield inconsistent bulk density (Db) across samples and result in values outside the typical ranges.
For example, a 100% pine bark substrate packed with the tap method yielded 0.14 g cm‑3 instead of the reported typical 0.20 g cm‑3, yet 100% Sphagnum peat packed with the tap method was 0.08 g cm‑3, in the center of the typical range, 0.06 to 0.10 g cm‑3. Additionally, ranges identified as typical in a laboratory may not reflect Db occurring through normal potting practices.
Packing to an insufficient Db can cause substrate shrinkage following saturation and drying, compromising the accuracy, precision, and applicability of subsequent static and dynamic physical properties.
Our objective was to document the Db associated with a potted 2.8-L (#1) container as an initial step toward developing a new laboratory packing method for substrates cores that will consistently achieve substrate Db commensurate with in situ nursery Db.
In this preliminary study, we demonstrate the influence of container potting practices and post-potting irrigation on Db.
Rings are packed by filling with loose substrate before being tapped on the benchtop; however, this method can yield inconsistent bulk density (Db) across samples and result in values outside the typical ranges.
For example, a 100% pine bark substrate packed with the tap method yielded 0.14 g cm‑3 instead of the reported typical 0.20 g cm‑3, yet 100% Sphagnum peat packed with the tap method was 0.08 g cm‑3, in the center of the typical range, 0.06 to 0.10 g cm‑3. Additionally, ranges identified as typical in a laboratory may not reflect Db occurring through normal potting practices.
Packing to an insufficient Db can cause substrate shrinkage following saturation and drying, compromising the accuracy, precision, and applicability of subsequent static and dynamic physical properties.
Our objective was to document the Db associated with a potted 2.8-L (#1) container as an initial step toward developing a new laboratory packing method for substrates cores that will consistently achieve substrate Db commensurate with in situ nursery Db.
In this preliminary study, we demonstrate the influence of container potting practices and post-potting irrigation on Db.
Authors
B. Alred, J.S. Owen, A. Espinoza, A. Fulcher
Keywords
coconut coir, container-grown crops, nursery crop, physical properties, pine bark, Sphagnum peat moss, soilless culture
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