Abstract
Changes in low-molecular-weight organic acids (LMWOAs), plant uptake or leaching of base cations (BCs) during peak crop growth affect soil acidity , particularly owing to excessive fertilizer use and intensive farming. The effect of LMWOAs and BCs on the acidity of Mollisol farmland is poorly understood. A long-term experiment with different fertilizer treatments under continuous cropping or corn–soybean rotation modules, was performed to examine the variation of LMWOAs and BCs during peak growth stages of corn and soybean and their effects on soil acidity. The LMWOAs concentrations ranged from 33.6 to 45.9 mg kg –1 at the jointing stage of corn and 71.2–114 mg kg –1 at the flowering stage of soybean. The predominant LMWOAs for corn are malic, acetic, and propanedioic acids, and malic, propanedioic, and succinic acids for soybean. Acetic acid was the main acidity determinant for corn ( r = 0.714, p < 0.001), whereas that for soybean was malic acid ( r = 0.704, p < 0.001). Acidification of the Mollisol farmland by LMWOAs and BCs during the peak crop growth stage is crop-specific and management-dependent. The higher total amount of LMWOAs may be one of the reasons for soil acidification in soybean. Continuous corn significantly increases the total LMWOAs concentration but reduces the content of BCs, exchangeable BCs (Ca 2+ , Mg 2+ , and Na + ), whereas continuous soybean reduces no effect on either LMWOAs or BCs. Continuous corn cultivation, compared to rotational corn, reduces soil pH from 5.76 to 5.63, due to an increase in the total LMWOAs concentration, as well as a reduction in BCs and exchangeable BCs (Ca 2+ , Mg 2+ , and Na + ) levels. There is no significant difference in soil pH between continuous and rotational soybean treatments but soil pH below 5.5 in both treatments. Rotation with chemical fertilizer for corn and dairy manure alone for soybean increases soil pH significantly owing to higher levels of BCs and exchangeable BCs (Ca 2+ , Mg 2+ , and K + ). Manure application is more effective than straw return in mitigating soil acidity. Understanding the decomposition dynamics of LMWOAs during the crop cycle on soil acidity is required to lay a robust scientific basis for mitigating soil acidification in Mollisol farmlands.
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Claims 13
Claim · model-written summary
LMWOA concentration at corn jointing ranged from 33.6 to 45.9 mg kg –1.
- Taxon
- corn
Zea mays subsp. mayse0 - Organ / stage
- jointing stagee0
- Outcome
- LMWOAs concentrationse0
- Value
- 33.6 to 45.9 mg kg –1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The LMWOAs concentrations ranged from 33.6 to 45.9 mg kg –1 at the jointing stage of corn”
Claim · model-written summary
LMWOA concentration at soybean flowering ranged from 71.2 to 114 mg kg –1.
- Taxon
- soybean
Glycine maxe0 - Organ / stage
- flowering stagee0
- Outcome
- LMWOAse1
- Value
- 71.2–114 mg kg –1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“71.2–114 mg kg –1 at the flowering stage of soybean”
t0“soil organic acids and base cations in Mollisol acidification during the peak growth stage of crops”
e1“The LMWOAs concentrations ranged from 33.6 to 45.9 mg kg –1 at the jointing stage of corn”
Claim · model-written summary
Malic, acetic and propanedioic acids predominated for corn.
- Taxon
- cornZea mays subsp. mayse0
- Outcome
- malic, acetic, and propanedioic acidse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The predominant LMWOAs for corn are malic, acetic, and propanedioic acids”
Claim · model-written summary
Malic, propanedioic and succinic acids predominated for soybean.
- Taxon
- soybeanGlycine maxe0
- Outcome
- malic, propanedioic, and succinic acidse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“malic, propanedioic, and succinic acids for soybean”
Claim · model-written summary
Acetic acid was the main determinant of soil acidity for corn.
- Taxon
- cornZea mays subsp. mayse0
- Compound
- Acetic acide0
- Outcome
- aciditye0
- Value
- r = 0.714e0
- Qualifier
- p < 0.001e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Acetic acid was the main acidity determinant for corn ( r = 0.714, p < 0.001)”
Claim · model-written summary
Malic acid was the main determinant of soil acidity for soybean.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“whereas that for soybean was malic acid ( r = 0.704, p < 0.001)”
t0“Mollisol acidification”
e1“Acetic acid was the main acidity determinant for corn ( r = 0.714, p < 0.001)”
Claim · model-written summary
Continuous corn increased total LMWOA concentration.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- Continuous corne0
- Outcome
- total LMWOAs concentratione0
- Direction
- increasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Continuous corn significantly increases the total LMWOAs concentration”
Claim · model-written summary
Continuous corn reduced base cations and exchangeable Ca, Mg and Na.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- Continuous cornt0
- Outcome
- content of BCs, exchangeable BCs (Ca 2+ , Mg 2+ , and Na + )e0
- Direction
- reducese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“reduces the content of BCs, exchangeable BCs (Ca 2+ , Mg 2+ , and Na + )”
t0“Continuous corn significantly increases the total LMWOAs concentration”
Claim · model-written summary
Continuous soybean did not affect LMWOAs or base cations.
- Taxon
- soybeanGlycine maxe0
- Treatment
- continuous soybeane0
- Outcome
- LMWOAs or BCse0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“continuous soybean reduces no effect on either LMWOAs or BCs”
Claim · model-written summary
Continuous corn reduced soil pH from 5.76 to 5.63 relative to rotational corn.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- Continuous corn cultivatione0
- Outcome
- soil pHe0
- Direction
- reducese0
- Value
- 5.76 to 5.63e0
- Comparator
- rotational corne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Continuous corn cultivation, compared to rotational corn, reduces soil pH from 5.76 to 5.63”
Claim · model-written summary
Soil pH did not differ significantly between continuous and rotational soybean.
- Taxon
- soybeanGlycine maxe0
- Treatment
- continuouse0
- Outcome
- soil pHe0
- Direction
- no significant differencee0
- Qualifier
- below 5.5e0
- Comparator
- rotational soybean treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There is no significant difference in soil pH between continuous and rotational soybean treatments but soil pH below 5.5 in both treatments”
Claim · model-written summary
Rotation with chemical fertilizer for corn and dairy manure for soybean significantly increased soil pH.
- Taxon
- corn and dairy manure alone for soybeane0
- Treatment
- Rotation with chemical fertilizer for corn and dairy manure alone for soybeane0
- Outcome
- soil pHe0
- Direction
- increasese0
Not reportedComparator
Verbatim
e0“Rotation with chemical fertilizer for corn and dairy manure alone for soybean increases soil pH significantly owing to higher levels of BCs and exchangeable BCs (Ca 2+ , Mg 2+ , and K + )”
Claim · model-written summary
Manure mitigated soil acidity more effectively than straw return.
Verbatim
e0“Manure application is more effective than straw return in mitigating soil acidity”
t0“peak growth stage of crops”
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See all 21 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.