Articles
RESIDUES OF ALEURITES FORDII (EUPHORBIACEAE) AS A COMPONENT FOR PLANT SUBSTRATES
Article number
644_21
Pages
171 – 176
Language
English
Abstract
The Chinese Tung tree is cultivated to obtain the raw material for the tung oil industry.
Tung husk (TH) is a by-product of this industry, composed of seed coats and fruit walls.
The high content of long-lasting fibers suggests that TH could be appropriate to be mixed in substrates for potted plants.
This study was conducted to verify the properties of TH as a component for growing media.
Samples of 6-month-aged TH were separated into granulometric fractions: <4.75 mm; >4.75 <9.5 mm; >9.5 <16 mm; <9.5 mm, and <30 mm representing the whole sample as received.
TH presented about 80% DM of particles <9.5 mm with a large amount (22% DM) of very fine particles <0.5 mm.
Particles > 9.5 mm represented about 11% DM. All size fractions showed high values of CEC (40 to 50 cmolc L-1) and pH 7. The natural salinity was low (0.3 to 0.4 g KCl L-1), adequate even to the most sensitive plants.
The effect of particle sizes was more evident on the physical properties.
Smaller particles influenced the values of bulk density, total porosity, easily available water and remaining moisture at 100 hPa, increasing density, porosity and water retention in micropores.
A high amount of humidity even after the drainage at 100 hPa is characteristic for TH, especially in samples with smaller particles.
Differences in mechanical impedance were observed between loose and firmed samples, especially for the smaller particle size.
Loose samples with particles sizes < 9.5 mm showed less resistance to penetration (< 100 kPa) while all of the others can be classified as of intermediate resistance (> 100 kPa). Considering the analyzed properties, TH is suitable as a potting media component.
The excessive moisture retention in micropores, however, can limit the use of TH in plugs and shallow containers.
Tung husk (TH) is a by-product of this industry, composed of seed coats and fruit walls.
The high content of long-lasting fibers suggests that TH could be appropriate to be mixed in substrates for potted plants.
This study was conducted to verify the properties of TH as a component for growing media.
Samples of 6-month-aged TH were separated into granulometric fractions: <4.75 mm; >4.75 <9.5 mm; >9.5 <16 mm; <9.5 mm, and <30 mm representing the whole sample as received.
TH presented about 80% DM of particles <9.5 mm with a large amount (22% DM) of very fine particles <0.5 mm.
Particles > 9.5 mm represented about 11% DM. All size fractions showed high values of CEC (40 to 50 cmolc L-1) and pH 7. The natural salinity was low (0.3 to 0.4 g KCl L-1), adequate even to the most sensitive plants.
The effect of particle sizes was more evident on the physical properties.
Smaller particles influenced the values of bulk density, total porosity, easily available water and remaining moisture at 100 hPa, increasing density, porosity and water retention in micropores.
A high amount of humidity even after the drainage at 100 hPa is characteristic for TH, especially in samples with smaller particles.
Differences in mechanical impedance were observed between loose and firmed samples, especially for the smaller particle size.
Loose samples with particles sizes < 9.5 mm showed less resistance to penetration (< 100 kPa) while all of the others can be classified as of intermediate resistance (> 100 kPa). Considering the analyzed properties, TH is suitable as a potting media component.
The excessive moisture retention in micropores, however, can limit the use of TH in plugs and shallow containers.
Authors
C. Gruszynski, A.N. Kämpf
Keywords
tung husks, growing media, physical and chemical properties, penetrability.
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