Abstract
Abstract Soybeans ( Glycine max L. Merr.) are becoming important in cropping systems that increase competition for light among crops. One of the products of N 2 ‐fixation is protein production. A field study was conducted to determine the effects of various degrees of shading (0,20,47, 63, 80, and 93%) on soybean No‐fixation, grain yield, and plant composition. The soil was a Flanagan series, a fine, montmorillonitic, mesic Aquic Argiudoll. Ambient illumination was 124.2 klux. Various degrees of shading were obtained by using different screens. Acetylene‐ethylene assay was used to determine N 2 ‐fixation. Shading accelerated the rate of loss of total nodule N 2 ‐fixing activity (TNA) as plants developed. The average TNA and dry weight of plant tops were highest at 20% shade (99.3 Klux) and decreased curvilinearly as shading increased, while specific nodule activity decreased linearly. Grain yields under 20, 47, 63, 80, and 93% shade were 90, 75, 48, 18, and 2% of unshaded plants. Seed percent protein and oil content of the seed were virtually unaffected between 20 and 80% shade. The highest percent protein and lowest percent oil occurred at 93% shade. Number of pods per plant percent leaf N, total stem N, TNA, and grain yield were highly correlated with shading and may be good selection indices for soybean shade tolerance. Soybean N 2 ‐fixation was positively correlated with seed protein content (r = 0.77) but negatively correlated with seed protein (r = −0.44). Cropping practices should allow at least 80% ambient illumination measured at the height of 50 cm for substantial soybean No‐fixation.
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Claims 16
Claim · model-written summary
Shading accelerated loss of total nodule nitrogen-fixing activity during development.
- Taxon
- Soybeans
Glycine maxt0 - Treatment
- Shadinge0
- Outcome
- rate of loss of total nodule N 2 ‐fixing activity (TNA)e0
- Direction
- acceleratede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Shading accelerated the rate of loss of total nodule N 2 ‐fixing activity (TNA) as plants developed”
t0“Soybeans”
Claim · model-written summary
Mean total nodule activity was highest at 20% shade and decreased as shading increased.
- Taxon
- SoybeansGlycine maxt0
- Treatment
- 20% shadee0
- Outcome
- average TNAe0
- Direction
- higheste0
- Value
- 99.3 Kluxe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The average TNA and dry weight of plant tops were highest at 20% shade (99.3 Klux) and decreased curvilinearly as shading increased”
t0“Soybeans”
Claim · model-written summary
Plant-top dry weight was highest at 20% shade and declined curvilinearly with more shade.
- Taxon
- SoybeansGlycine maxt0
- Treatment
- 20% shadee0
- Outcome
- dry weight of plant topse0
- Direction
- higheste0
- Qualifier
- decreased curvilinearly as shading increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The average TNA and dry weight of plant tops were highest at 20% shade (99.3 Klux) and decreased curvilinearly as shading increased”
t0“Soybeans”
Claim · model-written summary
Specific nodule activity fell linearly as shade increased.
- Taxon
- SoybeansGlycine maxt0
- Treatment
- shadinge1
- Outcome
- specific nodule activitye0
- Direction
- decreasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“specific nodule activity decreased linearly”
e1“as shading increased”
t0“Soybeans”
Claim · model-written summary
At 20% shade soybean grain yield was 90% of unshaded plants.
- Taxon
- SoybeansGlycine maxt0
- Treatment
- 20e0
- Outcome
- Grain yieldse0
- Direction
- lowerinferrede0
- Value
- 90e0
- Comparator
- unshaded plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Grain yields under 20, 47, 63, 80, and 93% shade were 90, 75, 48, 18, and 2% of unshaded plants”
t0“Soybeans”
Claim · model-written summary
At 47% shade soybean grain yield was 75% of unshaded plants.
- Taxon
- SoybeansGlycine maxt0
- Treatment
- 47e0
- Outcome
- Grain yieldse0
- Direction
- lowerinferrede0
- Value
- 75e0
- Comparator
- unshaded plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Grain yields under 20, 47, 63, 80, and 93% shade were 90, 75, 48, 18, and 2% of unshaded plants”
t0“Soybeans”
Claim · model-written summary
At 63% shade soybean grain yield was 48% of unshaded plants.
- Taxon
- SoybeansGlycine maxt0
- Treatment
- 63e0
- Outcome
- Grain yieldse0
- Direction
- lowerinferrede0
- Value
- 48e0
- Comparator
- unshaded plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Grain yields under 20, 47, 63, 80, and 93% shade were 90, 75, 48, 18, and 2% of unshaded plants”
t0“Soybeans”
Claim · model-written summary
At 80% shade soybean grain yield was 18% of unshaded plants.
- Taxon
- SoybeansGlycine maxt0
- Treatment
- 80e0
- Outcome
- Grain yieldse0
- Direction
- lowerinferrede0
- Value
- 18e0
- Comparator
- unshaded plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Grain yields under 20, 47, 63, 80, and 93% shade were 90, 75, 48, 18, and 2% of unshaded plants”
t0“Soybeans”
Claim · model-written summary
At 93% shade soybean grain yield was 2% of unshaded plants.
- Taxon
- SoybeansGlycine maxt0
- Treatment
- 93e0
- Outcome
- Grain yieldse0
- Direction
- lowerinferrede0
- Value
- 2%e0
- Comparator
- unshaded plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Grain yields under 20, 47, 63, 80, and 93% shade were 90, 75, 48, 18, and 2% of unshaded plants”
t0“Soybeans”
Claim · model-written summary
Seed protein and oil content were virtually unchanged over 20-80% shade.
- Taxon
- SoybeansGlycine maxt0
- Treatment
- 20 and 80% shadee0
- Outcome
- Seed percent protein and oil content of the seede0
- Direction
- virtually unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seed percent protein and oil content of the seed were virtually unaffected between 20 and 80% shade”
t0“Soybeans”
Claim · model-written summary
Seed protein percentage was highest at 93% shade.
- Taxon
- SoybeansGlycine maxt0
- Treatment
- 93% shadee0
- Outcome
- percent proteine0
- Direction
- higheste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The highest percent protein and lowest percent oil occurred at 93% shade”
t0“Soybeans”
Claim · model-written summary
Seed oil percentage was lowest at 93% shade.
- Taxon
- SoybeansGlycine maxt0
- Treatment
- 93% shadee0
- Outcome
- percent oile0
- Direction
- loweste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The highest percent protein and lowest percent oil occurred at 93% shade”
t0“Soybeans”
Claim · model-written summary
Pods per plant, leaf nitrogen, stem nitrogen, total nodule activity and yield were highly correlated with shading.
- Taxon
- SoybeansGlycine maxt0
- Treatment
- shadinge0
- Outcome
- Number of pods per plant percent leaf N, total stem Ne0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Number of pods per plant percent leaf N, total stem N, TNA, and grain yield were highly correlated with shading”
t0“Soybeans”
Claim · model-written summary
Soybean nitrogen fixation positively correlated with seed protein content (r = 0.77).
- Taxon
- SoybeanGlycine maxe0
- Outcome
- N 2 ‐fixatione0
- Direction
- positively correlatede0
- Value
- r = 0.77e0
- Comparator
- seed protein contente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soybean N 2 ‐fixation was positively correlated with seed protein content (r = 0.77)”
Claim · model-written summary
Soybean nitrogen fixation negatively correlated with seed protein (r = −0.44), as separately stated in the abstract.
- Taxon
- SoybeanGlycine maxe1
- Outcome
- N 2 ‐fixatione1
- Direction
- negatively correlatede0
- Value
- r = −0.44e0
- Comparator
- seed proteine0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“but negatively correlated with seed protein (r = −0.44)”
e1“Soybean N 2 ‐fixation was positively correlated with seed protein content”
Claim · model-written summary
Authors recommend at least 80% ambient illumination at 50 cm for substantial soybean fixation.
- Taxon
- soybeanGlycine maxe0
- Outcome
- allow at least 80% ambient illuminatione0
- Value
- 80%e0
- Qualifier
- height of 50 cme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cropping practices should allow at least 80% ambient illumination measured at the height of 50 cm for substantial soybean No‐fixation”
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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.