Abstract
Pollution of agricultural soil with heavy metals is a serious hazard to the environment and human health. The application of biochar can be a cost-effective and environmentally friendly way to reduce heavy metal bioavailability in contaminated soils and thus their uptake by plants. A pot experiment was conducted to evaluate the effect of three types of biochar (mango, Casuarina and Salix as feedstocks) at two application rates (2% and 4% w/w) on soil characteristics, heavy metal availability in soil and bioaccumulation in plants, as well as the growth of summer squash grown in highly polluted soil. The results indicated that the highest dry weight of root and shoot was recorded at the lowest application rate of Casuarina biochar followed by mango and Salix biochars. Compared to untreated soil, the adding of Casuarina biochar at 4% decreased the concentrations of Cd, Co, Cr, Cu, Ni, Pb and Zn by 25.7%, 52.1%, 12.1%, 32.3%, 31.0%, 85.0% and 25.2% in the root, and by 37.2%, 66.9%, 24.3%, 40.2%, 42.0%, 89.2% and 35.5% in the shoot, respectively. Casuarina biochar at 4% treatment was found to be the most effective in reducing the uptake of heavy metals by roots and shoots. Also, this treatment had the highest significant reductions in the availability of heavy metals over the untreated soil. The reductions in bioconcentration factor and translocation factor achieved with biochar application varied significantly for different types and rates of biochars. All biochar applications increased significantly soil pH, organic matter and electrical conductivity compared to untreated soil. It can be concluded that Casuarina biochar has great potential as a soil amendment for increasing the heavy metal immobilization, reducing the availability and plant uptake of heavy metals, and enhancing the growth of summer squash plants.
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Claims 9
Claim · model-written summary
The lowest rate of Casuarina biochar produced the highest root dry weight.
Verbatim
e0“the highest dry weight of root and shoot was recorded at the lowest application rate of Casuarina biochar followed by mango and Salix biochars”
t0“summer squash”
Claim · model-written summary
The lowest rate of Casuarina biochar produced the highest shoot dry weight.
Verbatim
e0“the highest dry weight of root and shoot was recorded at the lowest application rate of Casuarina biochar followed by mango and Salix biochars”
t0“summer squash”
Claim · model-written summary
At 4%, Casuarina biochar reduced root Cd, Co, Cr, Cu, Ni, Pb and Zn concentrations by their reported respective percentages.
Verbatim
e0“Compared to untreated soil, the adding of Casuarina biochar at 4% decreased the concentrations of Cd, Co, Cr, Cu, Ni, Pb and Zn by 25.7%, 52.1%, 12.1%, 32.3%, 31.0%, 85.0% and 25.2% in the root”
t0“summer squash”
Claim · model-written summary
At 4%, Casuarina biochar reduced shoot Cd, Co, Cr, Cu, Ni, Pb and Zn concentrations by their reported respective percentages.
Verbatim
e0“the adding of Casuarina biochar at 4% decreased the concentrations of Cd, Co, Cr, Cu, Ni, Pb and Zn by 25.7%, 52.1%, 12.1%, 32.3%, 31.0%, 85.0% and 25.2% in the root, and by 37.2%, 66.9%, 24.3%, 40.2%, 42.0%, 89.2% and 35.5% in the shoot, respectively”
e1“Compared to untreated soil”
t0“summer squash”
Claim · model-written summary
Casuarina biochar at 4% reduced metal uptake in roots and shoots most effectively.
- Taxon
- summer squasht0
- Treatment
- Casuarina biochar at 4%e0
- Outcome
- uptake of heavy metals by roots and shootse0
- Direction
- reducinge0
Not reportedComparator
Verbatim
e0“Casuarina biochar at 4% treatment was found to be the most effective in reducing the uptake of heavy metals by roots and shoots”
t0“summer squash”
Claim · model-written summary
Casuarina biochar at 4% gave the largest significant reduction in soil heavy-metal availability.
Verbatim
e0“this treatment had the highest significant reductions in the availability of heavy metals over the untreated soil”
e1“Casuarina biochar at 4% treatment”
t0“summer squash”
Claim · model-written summary
Biochar reductions in bioconcentration factor varied significantly by type and rate.
Verbatim
e0“The reductions in bioconcentration factor and translocation factor achieved with biochar application varied significantly for different types and rates of biochars”
t0“summer squash”
Claim · model-written summary
Biochar reductions in translocation factor varied significantly by type and rate.
Verbatim
e0“The reductions in bioconcentration factor and translocation factor achieved with biochar application varied significantly for different types and rates of biochars”
t0“summer squash”
Claim · model-written summary
All biochar applications significantly increased soil pH, organic matter and electrical conductivity.
Verbatim
e0“All biochar applications increased significantly soil pH, organic matter and electrical conductivity compared to untreated soil”
t0“summer squash”
The same questions in other papers
Casuarina · growth · Cucurbita (pumpkins)Positive and negative results
1 reporting no difference from an alternative
- no effect
biochar · growth · Cucurbita (pumpkins)Results agree
1 paper in the same direction as this paper
- positive
biochar · nutrient: content · Cucurbita (pumpkins)Results agree
1 paper in the same direction as this paper
- positive
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.