Articles
CHANGES IN PHYSICAL PROPERTIES OF COIR DUST SUBSTRATES DURING CROP PRODUCTION
Article number
644_35
Pages
261 – 268
Language
English
Abstract
Seven root substrates based on sphagnum peat moss substituted by coir dust in increments of one-sixth volume from 0 to 100% coir dust and a commercial control substrate, Metro Mix 366P, were tested in two similar experiments in a glass greenhouse.
These substrates were used to grow Impatiens wallerana L. in 14 cm plastic pots for the purpose of measuring the physical properties of these substrates at the start of the crop and changes in these properties during crop growth.
The 67% peat moss – 33% coir blend was the best for growth.
Container capacity (CC) and available water (AW), both expressed as percentage of substrate volume, bulk density (BD), and shrinkage decreased, compared to peat moss alone, during the first two irrigations as a consequence of coir addition during substrate formulation.
Air filled pore space at container capacity (AS) increased with increased coir.
When CC and AW were expressed as cc of water per plant container, CC increased while AW decreased modestly with increasing coir in the substrate.
During cropping time, regardless of substrate, BD rose modestly while AS and shrinkage decreased.
CC and AW, whether expressed as percentage of substrate volume or cc per pot, increased in the peat-coir mixtures.
By the end of the crop, coir, when compared to peat moss, resulted in lower CC and AW when expressed as % substrate volume and higher CC and AW when expressed as cc per pot.
This shift in results was due to less shrinkage in coir than peat moss and points out the greater commercial utility for expressing CC and AW on a pot basis rather than as a percentage of substrate volume.
Coir also resulted at the end of the crop in reductions in AS and BD. Shrinkage was modestly increased in experiment 1 and unaffected in experiment 2.
These substrates were used to grow Impatiens wallerana L. in 14 cm plastic pots for the purpose of measuring the physical properties of these substrates at the start of the crop and changes in these properties during crop growth.
The 67% peat moss – 33% coir blend was the best for growth.
Container capacity (CC) and available water (AW), both expressed as percentage of substrate volume, bulk density (BD), and shrinkage decreased, compared to peat moss alone, during the first two irrigations as a consequence of coir addition during substrate formulation.
Air filled pore space at container capacity (AS) increased with increased coir.
When CC and AW were expressed as cc of water per plant container, CC increased while AW decreased modestly with increasing coir in the substrate.
During cropping time, regardless of substrate, BD rose modestly while AS and shrinkage decreased.
CC and AW, whether expressed as percentage of substrate volume or cc per pot, increased in the peat-coir mixtures.
By the end of the crop, coir, when compared to peat moss, resulted in lower CC and AW when expressed as % substrate volume and higher CC and AW when expressed as cc per pot.
This shift in results was due to less shrinkage in coir than peat moss and points out the greater commercial utility for expressing CC and AW on a pot basis rather than as a percentage of substrate volume.
Coir also resulted at the end of the crop in reductions in AS and BD. Shrinkage was modestly increased in experiment 1 and unaffected in experiment 2.
Authors
P.V. Nelson, Y.-M. Oh, D.K. Cassel
Keywords
container capacity, air space, available water, bulk density, shrinkage, Impatiens wallerana L.
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