Abstract
Although it is known that immature composts can depress plant growth, few studies have quantified this effect in real-world scenarios with field-grown crops. Glasshouse and field trials were used to investigate the effect of maturation of grease trap compost (GTC) on plant growth. Grease trap waste was composted for 7-14 d in an in-vessel reactor with shredded green waste, sawdust and chicken manure and matured in windrows for up to 6 weeks. In the glasshouse trial, compost samples were mixed with an equal volume of coarse sand and were compared with a standard mix of 3 parts composted pine bark to 1 part coarse sand (v/v). In these trials, fresh GTC suppressed germination and growth of both radish and alyssum compared to the standard mix. Two weeks maturation reduced phytotoxicity of GTC but it was still phytotoxic relative to the standard mix. After 6 weeks maturation, GTC performed as well as the standard mix in all measures of plant growth and germination except for plant height of alyssum. Fresh and mature GTC were also used as soil conditioners in field trials on a commercial vegetable farm in the Werribee irrigation district, Victoria, Australia. Treatments consisted of GTC at 5 or 10 t ha−1, nil compost or a pelletised poultry manure product (Zest®) at 618 kg ha−1 arranged in a factorial design with 100% and 75% of the grower's standard fertilizer rate (741 kg ha−1 Rustica-Plus®). Head weight of lettuce was significantly reduced (by up to 18%) by the application of 10 t ha−1 of fresh GTC at the grower's standard fertiliser rate. When the fertiliser rate was reduced to 75%, the negative impact of fresh GTC was less apparent. In contrast to the first crop, the performance of mature GTC compared to the controls was independent of fertilizer rate (soil amendment x fertilizer interaction not significant at p<0.05). Application of 5 and 10 t ha−1 of mature GTC increased head weight of lettuce by 11% and 12% respectively compared to the control plus Zest® treatment. This research highlights the need of a better understanding of the maturity requirements of composts for use as soil amendments and growing media in horticultural production.
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Claims 11
Claim · model-written summary
Fresh grease trap compost suppressed germination and growth of radish compared with the standard mix.
- Taxon
- radish
Raphanus sativuse1 - Treatment
- fresh GTCe1
- Outcome
- germination and growthe1
- Direction
- suppressede1
- Comparator
- standard mixe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“fresh GTC suppressed germination and growth of both radish and alyssum compared to the standard mix”
Claim · model-written summary
Fresh grease trap compost suppressed germination and growth of alyssum compared with the standard mix.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“fresh GTC suppressed germination and growth of both radish and alyssum compared to the standard mix”
Claim · model-written summary
Two weeks of maturation reduced the phytotoxicity of grease trap compost.
- Taxon
- radish and alyssumRaphanus sativus
Alyssume1 - Treatment
- Two weeks maturatione2
- Outcome
- phytotoxicity of GTCe2
- Direction
- reducede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“fresh GTC suppressed germination and growth of both radish and alyssum compared to the standard mix”
e2“Two weeks maturation reduced phytotoxicity of GTC but it was still phytotoxic relative to the standard mix”
Claim · model-written summary
Grease trap compost matured for two weeks remained phytotoxic relative to the standard mix.
- Taxon
- radish and alyssumRaphanus sativusAlyssume1
- Treatment
- Two weeks maturatione2
- Outcome
- phytotoxice2
- Comparator
- standard mixe2
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“fresh GTC suppressed germination and growth of both radish and alyssum compared to the standard mix”
e2“Two weeks maturation reduced phytotoxicity of GTC but it was still phytotoxic relative to the standard mix”
Claim · model-written summary
After six weeks of maturation, grease trap compost performed as well as the standard mix in measures of plant growth and germination.
- Taxon
- radish and alyssumRaphanus sativusAlyssume1
- Treatment
- After 6 weeks maturatione3
- Outcome
- measures of plant growth and germinatione3
- Direction
- no_changeinferrede3
- Comparator
- standard mixe3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“fresh GTC suppressed germination and growth of both radish and alyssum compared to the standard mix”
e3“After 6 weeks maturation, GTC performed as well as the standard mix in all measures of plant growth and germination except for plant height of alyssum”
Claim · model-written summary
After six weeks of maturation, grease trap compost gave lower plant height of alyssum than the standard mix.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“After 6 weeks maturation, GTC performed as well as the standard mix in all measures of plant growth and germination except for plant height of alyssum”
Claim · model-written summary
Fresh grease trap compost at 10 t ha-1 significantly reduced lettuce head weight by up to 18% at the grower standard fertiliser rate.
- Taxon
- lettuce
Lactuca sativae5 - Treatment
- application of 10 t ha−1 of fresh GTCe5
- Outcome
- Head weight of lettucee5
- Direction
- reducede5
- Value
- 18%e5
- Qualifier
- the grower's standard fertiliser ratee5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“Head weight of lettuce was significantly reduced (by up to 18%) by the application of 10 t ha−1 of fresh GTC at the grower's standard fertiliser rate”
Claim · model-written summary
When the fertiliser rate was reduced to 75%, the negative impact of fresh grease trap compost on lettuce was less apparent.
- Taxon
- lettuceLactuca sativae5
- Treatment
- the fertiliser rate was reduced to 75%e4
- Outcome
- negative impact of fresh GTCe4
- Direction
- decreaseinferrede4
- Comparator
- the grower's standard fertiliser ratee5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“When the fertiliser rate was reduced to 75%, the negative impact of fresh GTC was less apparent”
e5“Head weight of lettuce was significantly reduced (by up to 18%) by the application of 10 t ha−1 of fresh GTC at the grower's standard fertiliser rate”
Claim · model-written summary
The performance of mature compost relative to controls did not depend on fertilizer rate in lettuce.
- Taxon
- lettuceLactuca sativae5
- Treatment
- mature GTCe6
- Outcome
- performancee6
- Direction
- no_changeinferrede6
- Qualifier
- soil amendment x fertilizer interaction not significant at p<0.05e6
- Comparator
- the controlse6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“Head weight of lettuce was significantly reduced (by up to 18%) by the application of 10 t ha−1 of fresh GTC at the grower's standard fertiliser rate”
e6“In contrast to the first crop, the performance of mature GTC compared to the controls was independent of fertilizer rate (soil amendment x fertilizer interaction not significant at p<0.05)”
Claim · model-written summary
Five t ha-1 of mature grease trap compost increased lettuce head weight by 11% compared with the control plus Zest treatment.
- Taxon
- lettuceLactuca sativae5
- Treatment
- Application of 5 and 10 t ha−1 of mature GTCe7
- Outcome
- head weight of lettucee7
- Direction
- increasede7
- Value
- 11%e7
- Comparator
- the control plus Zest® treatmente7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“Head weight of lettuce was significantly reduced (by up to 18%) by the application of 10 t ha−1 of fresh GTC at the grower's standard fertiliser rate”
e7“Application of 5 and 10 t ha−1 of mature GTC increased head weight of lettuce by 11% and 12% respectively compared to the control plus Zest® treatment”
Claim · model-written summary
Ten t ha-1 of mature grease trap compost increased lettuce head weight by 12% compared with the control plus Zest treatment.
- Taxon
- lettuceLactuca sativae5
- Treatment
- Application of 5 and 10 t ha−1 of mature GTCe7
- Outcome
- head weight of lettucee7
- Direction
- increasede7
- Value
- 12%e7
- Comparator
- the control plus Zest® treatmente7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“Head weight of lettuce was significantly reduced (by up to 18%) by the application of 10 t ha−1 of fresh GTC at the grower's standard fertiliser rate”
e7“Application of 5 and 10 t ha−1 of mature GTC increased head weight of lettuce by 11% and 12% respectively compared to the control plus Zest® treatment”
The same questions in other papers
trap barrier · growth · Raphanus sativus (radish)Positive and negative results
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trap barrier · yield · Lactuca sativa (garden lettuce)Positive and negative results
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stage · growth · Raphanus sativus (radish)Positive and negative results
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See all 249 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.