Abstract
Abstract It is unknown if nitrogen (N) fertilizer application will ameliorate the yield loss associated with severe defoliation of soybean [Glycine max (L.) Merr.] at the R5 stage of growth. The objective of this field study was to investigate the interaction of N fertilization rate and extent of defoliation on soybean yield, seed weight, seed N concentration, and nodule activity. Field experiments were conducted in 1988 and 1989 on a Drummer silty clay loam (Typic Haplaquolls). Treatment variables were three cultivars: BSR 101, Chamberlain, and Elgin 87; three N fertilizer rates applied one day after defoliation: 0, 84, and 168 kg N ha‐1 as urea; and three levels of defoliation: 0, 50, and 75%. Grain yield was not significantly affected by N rate but did decrease with defoliation. Fertilizer N did not ameliorate the yield reduction associated with defoliation. Seed weight decreased linearly with increasing defoliation. Plants exposed to the most severe defoliation produced seed which weighed 1 g 100‐1 seed less than seed from nondefoliated plants. In 1989 seed weight of only the nondefoliated plants increased slightly with N rate, seed weight was not affected by N rate for any other year by defoliation treatment combination. Seed N concentration was not affected by N rate. Seed N concentration increased with defoliation in 1988 but not in 1989. Seed N concentration was not affected by defoliation in 1989. N fertilizer application and defoliation decreased nodule activity. Defoliated plants utilized nitrates in preference to dinitrogen fixation. Fertilizer N increased the concentration of nitrates in the plant, but the increase did not ameliorate the yield loss. Developing pods and seed are the predominate sink. The additional energy presumably required for dinitrogen fixation did not exacerbate the yield loss.
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Claims 14
Claim · model-written summary
N fertilizer rate did not significantly affect soybean grain yield.
- Taxon
- soybean
Glycine maxt0 - Treatment
- N ratee0
- Outcome
- Grain yielde0
- Direction
- no_changeinferrede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Grain yield was not significantly affected by N rate but did decrease with defoliation”
t0“nodule activity of soybean”
Claim · model-written summary
Defoliation decreased soybean grain yield.
- Taxon
- soybeanGlycine maxt0
- Treatment
- defoliatione0
- Outcome
- Grain yielde0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Grain yield was not significantly affected by N rate but did decrease with defoliation”
t0“nodule activity of soybean”
Claim · model-written summary
Fertilizer N did not ameliorate the yield reduction caused by defoliation.
- Taxon
- soybeanGlycine maxt0
- Treatment
- Fertilizer Ne1
- Outcome
- yield reduction associated with defoliatione1
- Direction
- no_changeinferrede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Fertilizer N did not ameliorate the yield reduction associated with defoliation”
t0“nodule activity of soybean”
Claim · model-written summary
Seed weight decreased linearly with increasing defoliation.
- Taxon
- soybeanGlycine maxt0
- Treatment
- increasing defoliatione2
- Outcome
- Seed weighte2
- Direction
- decreasede2
- Qualifier
- linearlye2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“Seed weight decreased linearly with increasing defoliation”
t0“nodule activity of soybean”
Claim · model-written summary
Seed from the most severely defoliated soybean plants weighed 1 g 100-1 seed less than seed from nondefoliated plants.
- Taxon
- soybeanGlycine maxt0
- Treatment
- most severe defoliatione3
- Outcome
- Seed weighte2
- Direction
- lesse3
- Value
- 1 g 100‐1 seede3
- Comparator
- nondefoliated plantse3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“Seed weight decreased linearly with increasing defoliation”
e3“Plants exposed to the most severe defoliation produced seed which weighed 1 g 100‐1 seed less than seed from nondefoliated plants”
t0“nodule activity of soybean”
Claim · model-written summary
N fertilizer rate did not affect seed N concentration of soybean.
- Taxon
- soybeanGlycine maxt0
- Treatment
- N ratee4
- Outcome
- Seed N concentratione4
- Direction
- no_changeinferrede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“Seed N concentration was not affected by N rate”
t0“nodule activity of soybean”
Claim · model-written summary
Defoliation increased seed N concentration of soybean in 1988.
- Taxon
- soybeanGlycine maxt0
- Treatment
- defoliatione5
- Outcome
- Seed N concentratione5
- Direction
- increasede5
- Qualifier
- in 1988e5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“Seed N concentration increased with defoliation in 1988 but not in 1989”
t0“nodule activity of soybean”
Claim · model-written summary
Defoliation did not affect seed N concentration of soybean in 1989.
- Taxon
- soybeanGlycine maxt0
- Treatment
- defoliatione6
- Outcome
- Seed N concentratione6
- Direction
- no_changeinferrede6
- Qualifier
- in 1989e6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e6“Seed N concentration was not affected by defoliation in 1989”
t0“nodule activity of soybean”
Claim · model-written summary
N fertilizer application decreased soybean nodule activity.
- Taxon
- soybeanGlycine maxt0
- Treatment
- N fertilizer applicatione7
- Outcome
- nodule activitye7
- Direction
- decreasede7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e7“N fertilizer application and defoliation decreased nodule activity”
t0“nodule activity of soybean”
Claim · model-written summary
Defoliation decreased soybean nodule activity.
- Taxon
- soybeanGlycine maxt0
- Treatment
- defoliatione7
- Outcome
- nodule activitye7
- Direction
- decreasede7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e7“N fertilizer application and defoliation decreased nodule activity”
t0“nodule activity of soybean”
Claim · model-written summary
Defoliated soybean plants used nitrates in preference to dinitrogen fixation.
- Taxon
- soybeanGlycine maxt0
- Treatment
- Defoliated plantse1
- Compound
- nitratese1
- Outcome
- utilized nitrates in preference to dinitrogen fixatione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Defoliated plants utilized nitrates in preference to dinitrogen fixation”
t0“nodule activity of soybean”
Claim · model-written summary
Fertilizer N increased nitrate concentration in soybean plants.
- Taxon
- soybeanGlycine maxt0
- Treatment
- Fertilizer Ne1
- Compound
- nitratese1
- Outcome
- concentration of nitrates in the plante1
- Direction
- increasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Fertilizer N increased the concentration of nitrates in the plant, but the increase did not ameliorate the yield loss”
t0“nodule activity of soybean”
Claim · model-written summary
Developing pods and seed are the predominant sink in soybean plants.
- Taxon
- soybeanGlycine maxt0
- Organ / stage
- Developing pods and seede1
- Outcome
- sinke1
- Qualifier
- predominatee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Developing pods and seed are the predominate sink”
t0“nodule activity of soybean”
Claim · model-written summary
The additional energy presumably needed for dinitrogen fixation did not worsen soybean yield loss.
- Taxon
- soybeanGlycine maxt0
- Outcome
- yield losse1
- Qualifier
- presumably required for dinitrogen fixatione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“The additional energy presumably required for dinitrogen fixation did not exacerbate the yield loss”
t0“nodule activity of soybean”
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