Abstract
A series of short‐term greenhouse experiments and laboratory incubations were conducted to evaluate the effect of macadamia ( Macadamia integrifolia Maiden & Betche) nut shell (MNS) charcoal with varying volatile matter (VM) content on soil properties and plant growth in two tropical soils. Lettuce ( Lactuca sativa L.) and corn ( Zea mays L.) were planted in an Andisol amended with four rates of MNS charcoal (0, 5, 10, and 20% w/w) containing relatively high VM content (225 g kg −1 ) with and without N fertilizer. Increasing rates of charcoal without N caused a significant decline in both lettuce and corn growth. Corn growth declined significantly with or without N at the two highest charcoal rates. In a third experiment, corn growth also declined significantly in an Ultisol amended with the MNS charcoal (5% w/w) with and without fertilizers. In a fourth experiment, charcoals with high VM (225 g kg −1 ) showed negative effects on plant growth while the low‐VM (63.0 g kg −1 ) charcoal supplemented with fertilizer showed a significant positive effect on corn growth. Results from the 2‐wk incubation experiments showed that high‐VM charcoal caused a significant decline in soil NH 4 + –N and a significant increase in soil respiration compared with the soil amended with low‐VM charcoal and the soil alone. We propose that phenolic compounds and other products in the high‐VM charcoal stimulated microbial growth and immobilization of plant‐available N. Our results demonstrate that VM content appears to be an important property of charcoal that has short‐term effects on soil N transformations and plant growth. Longer incubation experiments and field trials are needed to further elucidate the role of charcoal VM content on soil processes and plant growth.
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Claims 9
Claim · model-written summary
Increasing charcoal rates without nitrogen significantly reduced lettuce growth.
- Taxon
- lettuce
Lactuca sativae0 - Treatment
- Increasing rates of charcoal without Ne0
- Outcome
- growthe0
- Direction
- declinee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing rates of charcoal without N caused a significant decline in both lettuce and corn growth.”
Claim · model-written summary
Increasing charcoal rates without nitrogen significantly reduced corn growth.
- Taxon
- corn
Zea mays subsp. mayse0 - Treatment
- Increasing rates of charcoal without Ne0
- Outcome
- growthe0
- Direction
- declinee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing rates of charcoal without N caused a significant decline in both lettuce and corn growth.”
Claim · model-written summary
The two highest charcoal rates significantly reduced corn growth with or without nitrogen.
- Taxon
- CornZea mays subsp. mayse0
- Treatment
- two highest charcoal ratese0
- Outcome
- growthe0
- Direction
- declinede0
- Qualifier
- with or without Ne0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Corn growth declined significantly with or without N at the two highest charcoal rates.”
Claim · model-written summary
Five-percent nut-shell charcoal significantly reduced corn growth in an Ultisol with or without fertilizer.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- MNS charcoal (5% w/w)e0
- Outcome
- growthe0
- Direction
- declinede0
- Qualifier
- with and without fertilizerse0
- Setting
- Ultisole0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“corn growth also declined significantly in an Ultisol amended with the MNS charcoal (5% w/w) with and without fertilizers.”
Claim · model-written summary
High-VM charcoal negatively affected plant growth.
- Taxon
- plante0
- Treatment
- charcoals with high VM (225 g kg −1 )e0
- Outcome
- plant growthe0
- Direction
- negativee0
Not reportedComparator
Verbatim
e0“charcoals with high VM (225 g kg −1 ) showed negative effects on plant growth”
Claim · model-written summary
Low-VM charcoal with fertilizer significantly improved corn growth.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- low‐VM (63.0 g kg −1 ) charcoal supplemented with fertilizere0
- Outcome
- growthe0
- Direction
- positivee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the low‐VM (63.0 g kg −1 ) charcoal supplemented with fertilizer showed a significant positive effect on corn growth.”
Claim · model-written summary
High-VM charcoal significantly decreased soil ammonium nitrogen versus low-VM charcoal and soil alone.
- Treatment
- high‐VM charcoale0
- Outcome
- soil NH 4 + –Ne0
- Direction
- declinee0
- Comparator
- soil amended with low‐VM charcoal and the soil alonee0
Not reportedTaxon
Verbatim
e0“high‐VM charcoal caused a significant decline in soil NH 4 + –N and a significant increase in soil respiration compared with the soil amended with low‐VM charcoal and the soil alone.”
Claim · model-written summary
High-VM charcoal significantly increased soil respiration versus low-VM charcoal and soil alone.
- Treatment
- high‐VM charcoale0
- Outcome
- soil respiratione0
- Direction
- increasee0
- Comparator
- soil amended with low‐VM charcoal and the soil alonee0
Not reportedTaxon
Verbatim
e0“high‐VM charcoal caused a significant decline in soil NH 4 + –N and a significant increase in soil respiration compared with the soil amended with low‐VM charcoal and the soil alone.”
Claim · model-written summary
The authors propose that phenolic compounds and other products in high-VM charcoal stimulated microbes and immobilized plant-available nitrogen.
Verbatim
e0“We propose that phenolic compounds and other products in the high‐VM charcoal stimulated microbial growth and immobilization of plant‐available N.”
The same questions in other papers
charcoal · growth · Lactuca sativa (garden lettuce)Positive and negative results
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charcoal · growth · Zea mays (maize)Results agree
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1,195 papers in the same direction as this paper · 149 in the opposite direction · 20 reporting no difference from an alternative
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See all 1,365 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.