Abstract
An 8-year study on 20 important agricultural soils of New Jersey, in which use was made of the roots of alfalfa plants as cation-extracting agents, has led to the following conclusions: conditions approach the optimum for the cation nutrition of alfalfa when 65% of the exchange complex of the soil is occupied by Ca, 10% by Mg, 5% by K, and 20% by H. Ca is the dominant cation in the soil and K in the alfalfa plant. The plant tends to take up more K than it needs unless the Ca content of the soil is maintained at a relatively high level. When any one of the nutrient cations is deficient in the soil, more of the others move into the alfalfa, but the sum of the cation equivalent in the plant per unit weight of dry tissue tends to be a constant. The tendency of alfalfa to absorb more K than it requires makes it necessary to consider how this can be avoided. K is a much more expensive element than the Ca which it replaces. Furthermore K is of much less importance, quantitatively, than Ca in the nutrition of animals. In soils of low exchange capacity, ormore » in those that are maintained at low pH values for the benefit of acid-soil crops, it would be desirable to apply moderate amounts of K from time to time during the crop season rather than a large amount at the time of planting only. Mg deficiency tends to be widespread on sandy and acid soils because the liberal applications of K that are normally used under such conditions enable the plant to absorb an excess of K in place of part of the needed Mg. Liming acid soils to the point where virtually all the exchange H in the entire volume of plowed soil has been replaced by Ca tends to cause a deficiency of Mn in crops other than the deep-rooted perennials.« less
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Claims 8
Claim · model-written summary
Alfalfa cation nutrition approached optimum at the stated soil exchange composition.
- Taxon
- alfalfa
Medicago sativae0 - Outcome
- cation nutritione0
- Qualifier
- 65% of the exchange complex of the soil is occupied by Ca, 10% by Mg, 5% by K, and 20% by He0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“conditions approach the optimum for the cation nutrition of alfalfa when 65% of the exchange complex of the soil is occupied by Ca, 10% by Mg, 5% by K, and 20% by H”
Claim · model-written summary
K was the dominant cation in alfalfa.
- Taxon
- alfalfaMedicago sativae0
- Outcome
- K in the alfalfa plante0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ca is the dominant cation in the soil and K in the alfalfa plant”
Claim · model-written summary
Alfalfa tended to take up excess K unless soil Ca remained high.
- Taxon
- alfalfaMedicago sativae2
- Outcome
- take up more K than it needse0
- Direction
- moree0
- Qualifier
- Ca content of the soil is maintained at a relatively high levele0
- Setting
- soile0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The plant tends to take up more K than it needs unless the Ca content of the soil is maintained at a relatively high level”
e2“roots of alfalfa plants as cation-extracting agents”
Claim · model-written summary
Deficiency of one soil nutrient cation increased uptake of others into alfalfa.
- Taxon
- alfalfaMedicago sativae0
- Outcome
- more of the others move into the alfalfae0
- Direction
- moree0
- Qualifier
- any one of the nutrient cations is deficient in the soile0
- Setting
- soile0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When any one of the nutrient cations is deficient in the soil, more of the others move into the alfalfa”
Claim · model-written summary
Total cation equivalents per dry tissue mass tended to remain constant.
- Taxon
- alfalfaMedicago sativae2
- Outcome
- sum of the cation equivalent in the plant per unit weight of dry tissuee0
- Direction
- constante0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the sum of the cation equivalent in the plant per unit weight of dry tissue tends to be a constant”
e2“roots of alfalfa plants as cation-extracting agents”
Claim · model-written summary
The authors recommend moderate repeated K applications in low exchange capacity or low pH soils.
- Taxon
- alfalfaMedicago sativae2
- Outcome
- apply moderate amounts of K from time to time during the crop seasone0
- Comparator
- a large amount at the time of planting onlye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“it would be desirable to apply moderate amounts of K from time to time during the crop season rather than a large amount at the time of planting only”
e2“roots of alfalfa plants as cation-extracting agents”
Claim · model-written summary
Mg deficiency tended to be widespread on sandy and acid soils.
- Taxon
- alfalfaMedicago sativae2
- Outcome
- Mg deficiencye0
- Setting
- sandy and acid soilse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Mg deficiency tends to be widespread on sandy and acid soils”
e2“roots of alfalfa plants as cation-extracting agents”
Claim · model-written summary
Liming acid soils to replace exchange H with Ca tended to cause Mn deficiency in other crops.
Not reportedComparatorDirection
Verbatim
e0“Liming acid soils to the point where virtually all the exchange H in the entire volume of plowed soil has been replaced by Ca tends to cause a deficiency of Mn in crops other than the deep-rooted perennials”
The same questions in other papers
ph · nutrient: content · Medicago sativa (alfalfa)Positive and negative results
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- positive
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See all 8 papers →lime · nutrient: content · Medicago sativa (alfalfa)Positive and negative results
6 papers in the same direction as this paper · 22 in the opposite direction
- positive
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See all 29 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.