Abstract
Abstract A glasshouse pot trial was designed to investigate the effects of bulk density on the root and shoot growth of two pipeline perennial ryegrass (Lolium perenne) lines, NZA1 and NZA3, and a commercial cultivar Yatsyn 1, in a soil derived from volcanic tephra in New Zealand. Bulk densities of 0.9, 1.0, 1.1, and 1.2 Mg/m3 were achieved in the subsoil growing medium as a subsurface layer in pots that were arranged in a complete factorial design, and caused penetration resistances of 2.2, 2.9, 3.6, and 4.4 MPa, respectively. Five harvests of herbage were made over 24 weeks from planting. At the final harvest, roots in the surface, subsurface, and lower pot strata were separated from the soil. Estimates of root length and dry weight were made. Increasing subsurface soil bulk density reduced root length from 20.4 to 8.4 m per pot stratum ( P < 0.05). This decrease in root development was associated with decreased ( P < 0.05) herbage yield (4.72 to 2.38 g/ pot) and tillering, showing that the increased mechanical impedance encountered by roots affected overall plant growth. The three ryegrasses produced similar total root length, herbage yield, and tiller numbers. However, the root length, herbage yield, and tillering of Yatsyn 1 were not significantly reduced as bulk density increased from 0.9 to 1.2 Mg/m3, although few significant interactions were detected. This was in contrast to the responses of NZA1 and NZA3 and shows that Yatsyn 1 was the least sensitive to the effects of soil compaction. Adverse affects on ryegrass root and shoot growth were shown at lower soil bulk densities (<1.3 Mg/m3) than are commonly reported. It is suggested that reduced plant growth in response to compaction may be occurring at lower bulk density in soils derived from volcanic parent material than those usually reported.
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Claims 8
Claim · model-written summary
Increasing soil bulk density reduced root length from 20.4 to 8.4 m per pot stratum.
- Taxon
- soil bulk densitye0
- Treatment
- Increasing subsurface soil bulk densitye0
- Outcome
- root lengthe0
- Direction
- reducede0
- Value
- 20.4 to 8.4 m per pot stratume0
Not reportedComparator
Verbatim
e0“Increasing subsurface soil bulk density reduced root length from 20.4 to 8.4 m per pot stratum ( P < 0.05)”
Claim · model-written summary
Decreased root development was associated with decreased herbage yield.
Not reportedTaxon
Verbatim
e0“This decrease in root development was associated with decreased ( P < 0.05) herbage yield (4.72 to 2.38 g/ pot) and tillering”
Claim · model-written summary
Decreased root development was associated with decreased tillering.
Not reportedTaxon
Verbatim
e0“This decrease in root development was associated with decreased ( P < 0.05) herbage yield (4.72 to 2.38 g/ pot) and tillering”
Claim · model-written summary
The three ryegrasses had similar total root length, herbage yield, and tiller numbers.
LoliumOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The three ryegrasses produced similar total root length, herbage yield, and tiller numbers”
Claim · model-written summary
Yatsyn 1 root length, herbage yield, and tillering were not significantly reduced with increasing bulk density.
- Material
- Yatsyn 1e0
- Treatment
- bulk density increased from 0.9 to 1.2 Mg/m3e0
- Outcome
- root length, herbage yield, and tilleringe0
- Direction
- not significantly reducede0
Not reportedTaxonComparator
Verbatim
e0“the root length, herbage yield, and tillering of Yatsyn 1 were not significantly reduced as bulk density increased from 0.9 to 1.2 Mg/m3”
Claim · model-written summary
Yatsyn 1 was least sensitive to soil compaction relative to NZA1 and NZA3.
- Material
- Yatsyn 1e0
- Outcome
- least sensitive to the effects of soil compactione0
- Direction
- least sensitivee0
- Comparator
- NZA1 and NZA3e0
Not reportedTaxon
Verbatim
e0“This was in contrast to the responses of NZA1 and NZA3 and shows that Yatsyn 1 was the least sensitive to the effects of soil compaction”
Claim · model-written summary
Adverse root and shoot growth effects occurred below 1.3 Mg/m3.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Adverse affects on ryegrass root and shoot growth were shown at lower soil bulk densities (<1.3 Mg/m3) than are commonly reported”
Claim · model-written summary
Growth reductions may occur at lower bulk density in soils from volcanic parent material.
Not reportedTaxon
Verbatim
e0“reduced plant growth in response to compaction may be occurring at lower bulk density in soils derived from volcanic parent material than those usually reported”