Abstract
In hot humid climates with highly leached, variable charge soils, the yields of many crops are limited due to subsoil acidity. Although surface‐applied gypsum has been shown to be effective in ameliorating this acidity in ferruginous and aluminous soils, the length of time that the effect is likely to last has not been satisfactorily established. A number of long‐term experiments with gypsum incorporated into the topsoil at 10 and 35 Mg ha −1 were sampled to evaluate its effects on soil profile chemical properties and yields of corn ( Zea mays L.) and alfalfa ( Medicago sativa L.). Even after 16 yr, the gypsum effects were still clearly visible. Exchangeable Ca and SO 4 were higher down the soil profile in the gypsum than in the control treatment. A complementary reduction in exchangeable Al was observed in the gypsum treatment to the 80‐cm depth. However, pH was not greatly altered down the profile. This amelioration of the effects of subsoil acidity was reflected in improved crop yields of both corn (29–50%) and alfalfa (≈50%) on the gypsum treatments. Because the gypsum effect is so long‐lasting, its use as a subsoil acidity ameliorant becomes highly economic because the initially high cost can be amortized over an extended period of time.
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Claims 8
Claim · model-written summary
Gypsum effects remained visible after 16 years.
- Taxon
- corn
Zea mays subsp. mayse1 - Outcome
- gypsum effects were still clearly visiblee0
- Qualifier
- 16 yre0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Even after 16 yr, the gypsum effects were still clearly visible”
e1“yields of corn ( Zea mays L.) and alfalfa ( Medicago sativa L.)”
Claim · model-written summary
Exchangeable Ca was higher down the soil profile after gypsum treatment than control.
- Taxon
- cornZea mays subsp. mayse1
- Treatment
- gypsume0
- Outcome
- Exchangeable Cae0
- Direction
- highere0
- Comparator
- control treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exchangeable Ca and SO 4 were higher down the soil profile in the gypsum than in the control treatment”
e1“yields of corn ( Zea mays L.) and alfalfa ( Medicago sativa L.)”
Claim · model-written summary
Exchangeable SO 4 was higher down the soil profile after gypsum treatment than control.
- Taxon
- cornZea mays subsp. mayse1
- Treatment
- gypsume0
- Outcome
- SO 4e0
- Direction
- highere0
- Comparator
- control treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exchangeable Ca and SO 4 were higher down the soil profile in the gypsum than in the control treatment”
e1“yields of corn ( Zea mays L.) and alfalfa ( Medicago sativa L.)”
Claim · model-written summary
Exchangeable Al fell under gypsum to 80-cm depth.
- Taxon
- cornZea mays subsp. mayse1
- Treatment
- gypsum treatmente0
- Outcome
- exchangeable Ale0
- Direction
- reductione0
- Qualifier
- 80‐cm depthe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A complementary reduction in exchangeable Al was observed in the gypsum treatment to the 80‐cm depth”
e1“yields of corn ( Zea mays L.) and alfalfa ( Medicago sativa L.)”
Claim · model-written summary
Gypsum did not greatly alter pH down the profile.
- Taxon
- cornZea mays subsp. mayse1
- Treatment
- gypsume2
- Outcome
- pHe0
- Direction
- not greatly alterede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“pH was not greatly altered down the profile”
e1“yields of corn ( Zea mays L.) and alfalfa ( Medicago sativa L.)”
e2“in the gypsum treatment to the 80‐cm depth”
Claim · model-written summary
Gypsum improved corn yield by 29–50%.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- gypsum treatmentse0
- Outcome
- crop yieldse0
- Direction
- improvede0
- Value
- 29–50%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“improved crop yields of both corn (29–50%) and alfalfa (≈50%) on the gypsum treatments”
Claim · model-written summary
Gypsum improved alfalfa yield by about 50%.
- Taxon
- alfalfa
Medicago sativae0 - Treatment
- gypsum treatmentse0
- Outcome
- crop yieldse0
- Direction
- improvede0
- Value
- ≈50%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“improved crop yields of both corn (29–50%) and alfalfa (≈50%) on the gypsum treatments”
Claim · model-written summary
The authors judge gypsum use economic as a long-lasting subsoil acidity treatment.
- Taxon
- cornZea mays subsp. mayse1
- Outcome
- use as a subsoil acidity ameliorante0
- Qualifier
- highly economice0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“its use as a subsoil acidity ameliorant becomes highly economic because the initially high cost can be amortized over an extended period of time”
e1“yields of corn ( Zea mays L.) and alfalfa ( Medicago sativa L.)”
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See all 219 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.