Abstract
Abstract The yield response of soybean [ Glycine max (L.) Merr.] to foliar fertilization during reproductive stages has been inconsistent. This study evaluated soybean responses to foliar applications of a 3–8–15 (N–P–K) fertilizer at early vegetative stages in 48 trials conducted on Iowa soils that tested mostly optimum or above in P and K. In 1994, the treatments were a control, single applications of 19, 28, or 38 L ha −1 at the V5 stage, and 38 or 56 L ha −1 split as one‐half at the V5 stage and one‐half 8 or 9 d later. In 1995 and 1996, only the single rate of 28 L ha −1 and the split rate of 38 L ha −1 were used. The lowest and highest volumes used encompassed N‐P‐K rates of 0.8‐2.1‐3.9 to 2.4‐6.3‐11.7 kg ha −1 . All treatments were replicated four times. Some or all treatments increased yields in seven sites and decreased yields at two sites. Mean yield increases were 60 kg ha −1 in 1994 (not significant), 30 kg ha −1 in 1995 (not significant), 60 kg ha −1 in 1996, and 54 kg ha −1 across the 48 sites. Differences between treatments were small and inconsistent, and the single application of 28 L ha −1 (one of the lowest rates used) produced the highest mean yield increase across all responsive sites (375 kg ha −1 ). In 1994, the higher yield responses occurred on ridge‐till and no‐till fields and when the P concentration of young plants was low. No treatment caused leaf burning. Foliar fertilization seldom increased P and K concentrations of leaves at the R2 growth stage and did not affect plant maturity, grain moisture, or the weight of grains. No simple set of measurements explained the occurrence of yield responses. Results of factor and regression analyses suggested that responses tended to occur in soils with high cation exchange capacity, when plant‐available P was low, and/or when rainfall in spring and midsummer was low. This group of variables explained only 14 to 23% of the responses in different years, however. Effective use of foliar fertilization of soybean at early growth stages in areas with predominantly high‐testing soils requires further research to identify the conditions under which positive responses are more likely.
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Claims 18
Claim · model-written summary
Foliar fertilization increased soybean yields at seven sites.
- Taxon
- soybean
Glycine maxt0 - Treatment
- foliar applications of a 3–8–15 (N–P–K) fertilizere1
- Outcome
- yieldse3
- Direction
- increasede3
- Qualifier
- in seven sitese3
- Comparator
- controle2
- Setting
- Iowa soilse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Foliar Fertilization of Soybean at Early Vegetative Stages”
e1“This study evaluated soybean responses to foliar applications of a 3–8–15 (N–P–K) fertilizer at early vegetative stages in 48 trials conducted on Iowa soils”
e2“In 1994, the treatments were a control”
e3“Some or all treatments increased yields in seven sites and decreased yields at two sites”
Claim · model-written summary
Foliar fertilization decreased soybean yields at two sites.
- Taxon
- soybeanGlycine maxt0
- Treatment
- foliar applications of a 3–8–15 (N–P–K) fertilizere1
- Outcome
- yieldse3
- Direction
- decreasede3
- Qualifier
- at two sitese3
- Comparator
- controle2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Foliar Fertilization of Soybean at Early Vegetative Stages”
e1“This study evaluated soybean responses to foliar applications of a 3–8–15 (N–P–K) fertilizer at early vegetative stages in 48 trials conducted on Iowa soils”
e2“In 1994, the treatments were a control”
e3“Some or all treatments increased yields in seven sites and decreased yields at two sites”
Claim · model-written summary
Foliar fertilization increased mean soybean yield by 60 kg ha −1 in 1994, not significantly.
- Taxon
- soybeanGlycine maxt0
- Treatment
- foliar applications of a 3–8–15 (N–P–K) fertilizere1
- Outcome
- mean yield increasese4
- Direction
- increasese4
- Value
- 60 kg ha −1e4
- Qualifier
- in 1994e4
- Comparator
- controle2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Foliar Fertilization of Soybean at Early Vegetative Stages”
e1“This study evaluated soybean responses to foliar applications of a 3–8–15 (N–P–K) fertilizer at early vegetative stages in 48 trials conducted on Iowa soils”
e2“In 1994, the treatments were a control”
e4“Mean yield increases were 60 kg ha −1 in 1994 (not significant), 30 kg ha −1 in 1995 (not significant), 60 kg ha −1 in 1996, and 54 kg ha −1 across the 48 sites”
Claim · model-written summary
Foliar fertilization increased mean soybean yield by 30 kg ha −1 in 1995, not significantly.
- Taxon
- soybeanGlycine maxt0
- Treatment
- foliar applications of a 3–8–15 (N–P–K) fertilizere1
- Outcome
- mean yield increasese4
- Direction
- increasese4
- Value
- 30 kg ha −1e4
- Qualifier
- in 1995e4
- Comparator
- controle2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Foliar Fertilization of Soybean at Early Vegetative Stages”
e1“This study evaluated soybean responses to foliar applications of a 3–8–15 (N–P–K) fertilizer at early vegetative stages in 48 trials conducted on Iowa soils”
e2“In 1994, the treatments were a control”
e4“Mean yield increases were 60 kg ha −1 in 1994 (not significant), 30 kg ha −1 in 1995 (not significant), 60 kg ha −1 in 1996, and 54 kg ha −1 across the 48 sites”
Claim · model-written summary
Foliar fertilization increased mean soybean yield by 60 kg ha −1 in 1996.
- Taxon
- soybeanGlycine maxt0
- Treatment
- foliar applications of a 3–8–15 (N–P–K) fertilizere1
- Outcome
- mean yield increasese4
- Direction
- increasese4
- Value
- 60 kg ha −1e4
- Qualifier
- in 1996e4
- Comparator
- controle2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Foliar Fertilization of Soybean at Early Vegetative Stages”
e1“This study evaluated soybean responses to foliar applications of a 3–8–15 (N–P–K) fertilizer at early vegetative stages in 48 trials conducted on Iowa soils”
e2“In 1994, the treatments were a control”
e4“Mean yield increases were 60 kg ha −1 in 1994 (not significant), 30 kg ha −1 in 1995 (not significant), 60 kg ha −1 in 1996, and 54 kg ha −1 across the 48 sites”
Claim · model-written summary
Foliar fertilization increased mean soybean yield by 54 kg ha −1 across the 48 sites.
- Taxon
- soybeanGlycine maxt0
- Treatment
- foliar applications of a 3–8–15 (N–P–K) fertilizere1
- Outcome
- mean yield increasese4
- Direction
- increasese4
- Value
- 54 kg ha −1e4
- Qualifier
- across the 48 sitese4
- Comparator
- controle2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Foliar Fertilization of Soybean at Early Vegetative Stages”
e1“This study evaluated soybean responses to foliar applications of a 3–8–15 (N–P–K) fertilizer at early vegetative stages in 48 trials conducted on Iowa soils”
e2“In 1994, the treatments were a control”
e4“Mean yield increases were 60 kg ha −1 in 1994 (not significant), 30 kg ha −1 in 1995 (not significant), 60 kg ha −1 in 1996, and 54 kg ha −1 across the 48 sites”
Claim · model-written summary
A single 28 L ha −1 foliar application gave the highest mean yield increase across responsive sites, 375 kg ha −1.
- Taxon
- soybeanGlycine maxt0
- Treatment
- single application of 28 L ha −1e5
- Outcome
- mean yield increase across all responsive sitese5
- Direction
- higheste5
- Value
- 375 kg ha −1e5
- Qualifier
- one of the lowest rates usede5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Foliar Fertilization of Soybean at Early Vegetative Stages”
e5“the single application of 28 L ha −1 (one of the lowest rates used) produced the highest mean yield increase across all responsive sites (375 kg ha −1 )”
Claim · model-written summary
Differences between foliar fertilization treatments in soybean were small and inconsistent.
- Taxon
- soybeanGlycine maxt0
- Outcome
- Differences between treatmentse6
- Qualifier
- small and inconsistente6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Foliar Fertilization of Soybean at Early Vegetative Stages”
e6“Differences between treatments were small and inconsistent”
Claim · model-written summary
In 1994, higher soybean yield responses to foliar fertilization occurred when plant P concentration was low.
- Taxon
- soybeanGlycine maxt0
- Outcome
- yield responsese7
- Direction
- highere7
- Qualifier
- when the P concentration of young plants was lowe5
- Setting
- In 1994e7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Foliar Fertilization of Soybean at Early Vegetative Stages”
e7“In 1994, the higher yield responses occurred”
e5“when the P concentration of young plants was low”
Claim · model-written summary
No foliar fertilization treatment caused soybean leaf burning.
- Taxon
- soybeanGlycine maxt0
- Outcome
- leaf burninge1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Foliar Fertilization of Soybean at Early Vegetative Stages”
e1“No treatment caused leaf burning”
Claim · model-written summary
Foliar fertilization seldom increased P and K concentrations of soybean leaves at the R2 stage.
- Taxon
- soybeanGlycine maxt0
- Organ / stage
- leaves at the R2 growth stagee1
- Treatment
- Foliar fertilizatione1
- Outcome
- P and K concentrations of leavese1
- Direction
- seldom increasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Foliar Fertilization of Soybean at Early Vegetative Stages”
e1“Foliar fertilization seldom increased P and K concentrations of leaves at the R2 growth stage”
Claim · model-written summary
Foliar fertilization did not affect soybean maturity, grain moisture or grain weight.
- Taxon
- soybeanGlycine maxt0
- Treatment
- Foliar fertilizatione1
- Outcome
- plant maturity, grain moisture, or the weight of grainse2
- Direction
- did not affecte2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Foliar Fertilization of Soybean at Early Vegetative Stages”
e1“Foliar fertilization seldom increased P and K concentrations of leaves at the R2 growth stage”
e2“did not affect plant maturity, grain moisture, or the weight of grains”
Claim · model-written summary
No simple set of measured variables explained the occurrence of soybean yield responses to foliar fertilization.
- Taxon
- soybeanGlycine maxt0
- Outcome
- occurrence of yield responsese1
- Qualifier
- No simple set of measurements explainede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Foliar Fertilization of Soybean at Early Vegetative Stages”
e1“No simple set of measurements explained the occurrence of yield responses”
Claim · model-written summary
Soybean yield responses to foliar fertilization tended to occur in soils with high cation exchange capacity.
- Taxon
- soybeanGlycine maxt0
- Outcome
- responsese1
- Direction
- higherinferrede1
- Setting
- soils with high cation exchange capacitye1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Foliar Fertilization of Soybean at Early Vegetative Stages”
e1“responses tended to occur in soils with high cation exchange capacity”
Claim · model-written summary
Soybean yield responses to foliar fertilization tended to occur when plant-available P was low.
- Taxon
- soybeanGlycine maxt0
- Compound
- plant-available Pe2
- Outcome
- responsese1
- Direction
- higherinferrede1
- Qualifier
- when plant-available P was lowe2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Foliar Fertilization of Soybean at Early Vegetative Stages”
e1“responses tended to occur in soils with high cation exchange capacity”
e2“when plant-available P was low”
Claim · model-written summary
Soybean yield responses to foliar fertilization tended to occur when spring and midsummer rainfall was low.
- Taxon
- soybeanGlycine maxt0
- Outcome
- responsese1
- Direction
- higherinferrede1
- Qualifier
- when rainfall in spring and midsummer was lowe2
- Setting
- rainfall in spring and midsummere2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Foliar Fertilization of Soybean at Early Vegetative Stages”
e1“responses tended to occur in soils with high cation exchange capacity”
e2“when rainfall in spring and midsummer was low”
Claim · model-written summary
The group of tested variables explained only 14 to 23% of soybean yield responses across years.
- Taxon
- soybeanGlycine maxt0
- Outcome
- responsese1
- Value
- 14 to 23%e1
- Qualifier
- explained onlye1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Foliar Fertilization of Soybean at Early Vegetative Stages”
e1“explained only 14 to 23% of the responses in different years”
Claim · model-written summary
Effective foliar fertilization of soybean in predominantly high-testing soils needs further research on conditions with positive responses.
- Taxon
- soybeanGlycine maxt0
- Treatment
- foliar fertilizatione1
- Outcome
- Effective use of foliar fertilizatione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Foliar Fertilization of Soybean at Early Vegetative Stages”
e1“Effective use of foliar fertilization of soybean at early growth stages in areas with predominantly high-testing soils requires further research”
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