Abstract
Abstract Sewage sludge normally would not be applied on land where peanut ( Arachis hypogaea L.) or tobacco ( Nicotiana tabacum L.) are being grown because of possible contamination of peanut with pathogens and increased Cd concentration in tobacco. These crops, however, might be grown in rotation with other crops to which sludge had been applied. The residual effect of sewage sludge on metal concentrations in tobacco and peanut was evaluated in a greenhouse pot experiment with a Typic Hapludult soil from a field that received aerobically digested municipal sewage sludge at 0, 9, 18, and 27 Mg ha − yr −1 for 3 yr. Cumulative amount of metals applied at the 27‐Mg rate were (kg ha −1 ) 1.8 Cd, 39 Cu, 48 Cr, 9 Ni, 30 Pb, and 84 Zn. Sulfuric acid or Ca(OH) 2 was used to effect three soil pH regimes: 5.2, 5.8, and 6.4 (median value within each regime). Tobacco (‘Speight G‐28’) was grown to flowering and peanut (NC 7) was grown to maturity. At the termination of the experiment, soils were extracted with diethylenetriaminepentaacetic acid (DTPA) and Mehlich 3 extractant (M3) for metal analysis. Tobacco dry weight (averaged over pH) increased from 66 g pot −1 with no sludge to 94 g pot −1 at the highest sludge rate. Peanut kernel yield (averaged over pH) was depressed at the highest rate (35 g pot −1 ) as compared to the lower rates (mean of 48 g pot −1 ). At low pH peanut top growth was depressed by sludge (probably a result of Zn toxicity) and no kernels were formed at the medium and high rates. Sludge rates and soil pH had little effect on concentration of Cr and Pb in tobacco or peanut. Concentration of Cd, Ni, and Zn in tobacco and in peanut top growth decreased as soil pH increased to 5.8 to 6.0 but no decrease was noted at higher pH. Sludge rate effect was significant at low pH but diminished as pH increased. Concentration of Cd, Ni, and Zn declined but Cu concentration increased with increasing height of leaf on the tobacco stalk. Results of stepwise multiple regression using linear and quadratic forms of cumulative sludge rate, soil pH, and DTPA‐extractable metals and pH × rate and pH × DTPA‐extractable metals interactions as independent variables and metal concentration in the lower tobacco leaves or in peanut tops as dependent variables suggested DTPA would predict tissue metal concentrations better than would M3.
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Claims 12
Claim · model-written summary
Tobacco dry weight increased from 66 to 94 g per pot at the highest sludge rate.
- Taxon
- Tobacco
Nicotiana tabacume0 - Treatment
- highest sludge ratee0
- Outcome
- dry weighte0
- Direction
- increasede0
- Value
- 94 g pot −1e0
- Qualifier
- 66 g pot −1e0
- Comparator
- no sludgee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Tobacco dry weight (averaged over pH) increased from 66 g pot −1 with no sludge to 94 g pot −1 at the highest sludge rate.”
Claim · model-written summary
Peanut kernel yield was depressed at the highest sludge rate relative to lower rates.
- Taxon
- Peanut
Arachis hypogaeae0 - Treatment
- highest ratee0
- Outcome
- kernel yielde0
- Direction
- depressede0
- Value
- 35 g pot −1e0
- Qualifier
- mean of 48 g pot −1e0
- Comparator
- lower ratese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Peanut kernel yield (averaged over pH) was depressed at the highest rate (35 g pot −1 ) as compared to the lower rates (mean of 48 g pot −1 ).”
Claim · model-written summary
At low pH sludge depressed peanut top growth.
- Taxon
- peanutArachis hypogaeae0
- Treatment
- sludgee0
- Outcome
- top growthe0
- Direction
- depressede0
- Qualifier
- At low pHe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At low pH peanut top growth was depressed by sludge (probably a result of Zn toxicity)”
Claim · model-written summary
At low pH no peanut kernels formed at medium and high sludge rates.
- Taxon
- peanutArachis hypogaeat0
- Treatment
- medium and high ratese0
- Outcome
- no kernels were formede0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“no kernels were formed at the medium and high rates”
t0“peanut”
Claim · model-written summary
The authors suggest zinc toxicity caused suppressed peanut top growth at low pH.
- Taxon
- peanutArachis hypogaeae0
- Treatment
- sludgee0
- Compound
- Zne0
- Outcome
- top growth was depressede0
- Qualifier
- At low pHe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At low pH peanut top growth was depressed by sludge (probably a result of Zn toxicity)”
Claim · model-written summary
Sludge rates and pH had little effect on chromium and lead concentrations in both crops.
- Taxon
- tobacco or peanutArachis hypogaeaNicotiana tabacume0
- Treatment
- Sludge rates and soil pHe0
- Outcome
- concentration of Cr and Pbe0
- Direction
- little effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Sludge rates and soil pH had little effect on concentration of Cr and Pb in tobacco or peanut.”
Claim · model-written summary
Tobacco Cd, Ni and Zn concentrations declined as pH rose to 5.8 to 6.0, but not above.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- soil pHe0
- Outcome
- Concentration of Cd, Ni, and Zne0
- Direction
- decreasede0
- Qualifier
- 5.8 to 6.0 but no decrease was noted at higher pHe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Concentration of Cd, Ni, and Zn in tobacco and in peanut top growth decreased as soil pH increased to 5.8 to 6.0 but no decrease was noted at higher pH.”
Claim · model-written summary
Peanut top Cd, Ni and Zn concentrations declined as pH rose to 5.8 to 6.0, but not above.
- Taxon
- peanutArachis hypogaeae0
- Organ / stage
- top growthe0
- Treatment
- soil pHe0
- Outcome
- Concentration of Cd, Ni, and Zne0
- Direction
- decreasede0
- Qualifier
- 5.8 to 6.0 but no decrease was noted at higher pHe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Concentration of Cd, Ni, and Zn in tobacco and in peanut top growth decreased as soil pH increased to 5.8 to 6.0 but no decrease was noted at higher pH.”
Claim · model-written summary
Sludge rate effects on tissue metal concentrations were significant at low pH and diminished as pH rose.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- sludgee0
- Outcome
- Sludge rate effecte0
- Direction
- diminishede0
- Qualifier
- at low pHe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Sludge rate effect was significant at low pH but diminished as pH increased.”
t0“Tobacco”
Claim · model-written summary
Tobacco leaf Cd, Ni and Zn concentrations decreased with increasing leaf height.
- Taxon
- tobaccoNicotiana tabacume0
- Organ / stage
- leafe0
- Outcome
- Concentration of Cd, Ni, and Zne0
- Direction
- declinede0
- Qualifier
- with increasing heighte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Concentration of Cd, Ni, and Zn declined but Cu concentration increased with increasing height of leaf on the tobacco stalk.”
Claim · model-written summary
Tobacco leaf Cu concentration increased with increasing leaf height.
- Taxon
- tobaccoNicotiana tabacume0
- Organ / stage
- leafe0
- Outcome
- Cu concentratione0
- Direction
- increasede0
- Qualifier
- with increasing heighte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Concentration of Cd, Ni, and Zn declined but Cu concentration increased with increasing height of leaf on the tobacco stalk.”
Claim · model-written summary
DTPA was suggested to predict tissue metal concentrations better than M3.
- Taxon
- tobaccoNicotiana tabacume0
- Organ / stage
- lower tobacco leaves or in peanut topse0
- Outcome
- predict tissue metal concentrationse0
- Direction
- bettere0
- Comparator
- M3e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Results of stepwise multiple regression using linear and quadratic forms of cumulative sludge rate, soil pH, and DTPA‐extractable metals and pH × rate and pH × DTPA‐extractable metals interactions as independent variables and metal concentration in the lower tobacco leaves or in peanut tops as dependent variables suggested DTPA would predict tissue metal concentrations better than would M3.”
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See all 14 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.