Abstract
ABSTRACT High pH may limit micronutrient availability for soybean (Glycine max L. Merr.) on Blackland soils found in northeast Texas. However, it is not clear whether preplant additions of micronutrients will enhance soybean growth or yield on this soil. In three separate greenhouse studies, a pH 8.3 Houston Black clay (fine, smectitic, thermic Udic Haplusterts), with DTPA-extractable concentrations of 0.74 mg copper (Cu) kg−1, 3.74 mg manganese (Mn) kg−1, and 0.47 mg zinc (Zn) kg−1, was treated with CuSO4 (0, 25, 50, 75, and 100 ppm Cu), MnSO4 (0, 10, 20, 30, and 40 ppm Mn), or ZnSO4 (0, 2, 4, 6, and 8 ppm Zn). Pot size was 19 L and soil dry mass was 10 kg. Soybean (cv. Hutcheson) seed were planted in either February or April 2000 and seedlings were thinned to three per pot at the first true leaf stage. One leaf from each plant was harvested at growth stage R3 for nutrient analysis. Between 20 and 110 days after planting, five to six nondestructive leaf chlorophyll readings were obtained. Plants were destructively harvested at R6 (mid podfill) for nutrient and yield determination. No visible symptoms appeared through early reproductive growth, but by growth stage R5 (beginning seed), leaves from the 0 ppm Cu treatment were chlorotic. Chlorophyll (SPAD 502) values of the 3rd uppermost leaf during the R3 to R5 growth stages were greater when Cu, Mn, and Zn were added to the soil than in the 0 ppm treatment. Fruit yield (seed plus pod walls) at growth stage R6 was greater in pots receiving 25 to 100 ppm Cu, 20 to 40 ppm Mn, and 4 to 8 ppm Zn than in the check treatment. Total biomass was increased by 25 to 100 ppm Cu, but there was only a trend for Mn or Zn to increase biomass. Because fruit yield increases were observed as a result of an addition of the micronutrients applied individually, a combination of micronutrients may increase yield further. There was no evidence that the higher rates of Cu, Mn, or Zn caused reduced growth. In summary, these greenhouse results indicated that field studies testing the effects of Cu, Mn, and Zn on soybean yield on this calcareous soil are warranted.
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Claims 15
Claim · model-written summary
Soybean leaves without added copper became chlorotic by growth stage R5.
Not reportedDirection
Verbatim
e0“by growth stage R5 (beginning seed), leaves from the 0 ppm Cu treatment were chlorotic.”
Claim · model-written summary
Copper addition increased soybean leaf chlorophyll readings relative to no addition.
- Organ / stage
- 3rd uppermost leafe0
- Treatment
- Cue0
- Outcome
- Chlorophyll (SPAD 502) valuese0
- Direction
- greatere0
- Comparator
- 0 ppm treatmente0
Not reportedTaxon
Verbatim
e0“Chlorophyll (SPAD 502) values of the 3rd uppermost leaf during the R3 to R5 growth stages were greater when Cu, Mn, and Zn were added to the soil than in the 0 ppm treatment.”
Claim · model-written summary
Manganese addition increased soybean leaf chlorophyll readings relative to no addition.
- Taxon
- SOYBEAN
Glycine maxt0 - Organ / stage
- 3rd uppermost leafe0
- Treatment
- Mne0
- Outcome
- Chlorophyll (SPAD 502) valuese0
- Direction
- greatere0
- Comparator
- 0 ppm treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chlorophyll (SPAD 502) values of the 3rd uppermost leaf during the R3 to R5 growth stages were greater when Cu, Mn, and Zn were added to the soil than in the 0 ppm treatment.”
t0“SOYBEAN”
Claim · model-written summary
Zinc addition increased soybean leaf chlorophyll readings relative to no addition.
- Taxon
- SOYBEANGlycine maxt0
- Organ / stage
- 3rd uppermost leafe0
- Treatment
- Zne0
- Outcome
- Chlorophyll (SPAD 502) valuese0
- Direction
- greatere0
- Comparator
- 0 ppm treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chlorophyll (SPAD 502) values of the 3rd uppermost leaf during the R3 to R5 growth stages were greater when Cu, Mn, and Zn were added to the soil than in the 0 ppm treatment.”
t0“SOYBEAN”
Claim · model-written summary
Copper at 25 to 100 ppm increased soybean fruit yield over the check.
- Taxon
- SOYBEANGlycine maxt0
- Organ / stage
- seed plus pod wallse0
- Treatment
- 25 to 100 ppm Cue0
- Outcome
- Fruit yielde0
- Direction
- greatere0
- Comparator
- check treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fruit yield (seed plus pod walls) at growth stage R6 was greater in pots receiving 25 to 100 ppm Cu, 20 to 40 ppm Mn, and 4 to 8 ppm Zn than in the check treatment.”
t0“SOYBEAN”
Claim · model-written summary
Manganese at 20 to 40 ppm increased soybean fruit yield over the check.
- Taxon
- SOYBEANGlycine maxt0
- Treatment
- 20 to 40 ppm Mne0
- Outcome
- Fruit yielde0
- Direction
- greatere0
- Comparator
- check treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fruit yield (seed plus pod walls) at growth stage R6 was greater in pots receiving 25 to 100 ppm Cu, 20 to 40 ppm Mn, and 4 to 8 ppm Zn than in the check treatment.”
t0“SOYBEAN”
Claim · model-written summary
Zinc at 4 to 8 ppm increased soybean fruit yield over the check.
- Taxon
- SOYBEANGlycine maxt0
- Treatment
- 4 to 8 ppm Zne0
- Outcome
- Fruit yielde0
- Direction
- greatere0
- Comparator
- check treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fruit yield (seed plus pod walls) at growth stage R6 was greater in pots receiving 25 to 100 ppm Cu, 20 to 40 ppm Mn, and 4 to 8 ppm Zn than in the check treatment.”
t0“SOYBEAN”
Claim · model-written summary
Copper at 25 to 100 ppm increased soybean total biomass.
- Taxon
- SOYBEANGlycine maxt0
- Treatment
- 25 to 100 ppm Cue0
- Outcome
- Total biomasse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total biomass was increased by 25 to 100 ppm Cu, but there was only a trend for Mn or Zn to increase biomass.”
t0“SOYBEAN”
Claim · model-written summary
Manganese showed only a trend toward increased soybean biomass.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“there was only a trend for Mn or Zn to increase biomass.”
t0“SOYBEAN”
Claim · model-written summary
Zinc showed only a trend toward increased soybean biomass.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“there was only a trend for Mn or Zn to increase biomass.”
t0“SOYBEAN”
Claim · model-written summary
Higher copper rates showed no evidence of reduced soybean growth.
- Taxon
- SOYBEANGlycine maxt0
- Treatment
- higher rates of Cue0
- Outcome
- growthe0
- Direction
- no evidencee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was no evidence that the higher rates of Cu, Mn, or Zn caused reduced growth.”
t0“SOYBEAN”
Claim · model-written summary
Higher manganese rates showed no evidence of reduced soybean growth.
- Taxon
- SOYBEANGlycine maxt0
- Treatment
- higher rates of Cu, Mn, or Zne0
- Outcome
- growthe0
- Direction
- no evidencee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was no evidence that the higher rates of Cu, Mn, or Zn caused reduced growth.”
t0“SOYBEAN”
Claim · model-written summary
Higher zinc rates showed no evidence of reduced soybean growth.
- Taxon
- SOYBEANGlycine maxt0
- Treatment
- higher rates of Cu, Mn, or Zne0
- Outcome
- growthe0
- Direction
- no evidencee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was no evidence that the higher rates of Cu, Mn, or Zn caused reduced growth.”
t0“SOYBEAN”
Claim · model-written summary
The authors suggest a combination of micronutrients may further increase soybean yield.
- Taxon
- SOYBEANGlycine maxt0
- Treatment
- a combination of micronutrientse0
- Outcome
- yielde0
- Direction
- increasee0
- Qualifier
- maye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a combination of micronutrients may increase yield further.”
t0“SOYBEAN”
Claim · model-written summary
The authors recommend field studies of copper, manganese, and zinc effects on soybean yield on this calcareous soil.
- Taxon
- soybeanGlycine maxe0
- Outcome
- field studies testing the effects of Cu, Mn, and Zn on soybean yielde0
- Setting
- this calcareous soile0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“field studies testing the effects of Cu, Mn, and Zn on soybean yield on this calcareous soil are warranted.”
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8 of 9 groups shown: named compounds and organisms first, then groups whose results differ (checked claim by claim), then those with positive and negative results, then the smaller groups.
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.