Abstract
Crops under furrow irrigation or after heavy rainfall on the alkaline, calcareous Vertisols of northern N.S.W. frequently exhibit chlorosis of young leaves after the soil is wetted, but the specific cause has not been identified previously. The quantitative effects of the syndrome on growth, physiological activity and yield are also unknown. Experiments on soybean and pigeon pea grown on a Vertisol at Breeza, N.S.W., Australia, examined the influence of applying Fe to the leaves, and Fe, Zn, N+P and lime to the soil before sowing, on leaf colour, leaf photosynthesis, crop dry matter, and yield of grain of soybean and dry matter and yield of pigeon pea. In soybean, chelated Fe applied to the soil before sowing increased the levels of active Fe (Fe2+) in leaves by up to 42% and dry matter of shoots by up to 46% early in the season. Active Fe and dry matter of shoots were linearly correlated (r2 = 0.76). Soil Fe treatments did not affect leaf photosynthesis, although addition of chelated Fe to the soil resulted in greener leaves than in the control. Foliar Fe had no significant effect on active Fe, leaf colour, or leaf photosynthesis. The 9% increase in grain yield in response to application of 20 kg Fe ha-1 to the soil was not significant. In pigeon pea, application of 20 kg Fe ha-1 to the soil increased dry matter by 140% and grain yield by 414%. Effects of lime and zinc were not significant, but N+P increased yield by 112%. The study showed that Fe deficiency is limiting the growth and/or yield of irrigated soybean and pigeon pea on the clay soils of northern N.S.W., and pointed to lime-induced iron chlorosis as a possible mechanism of damage.
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Claims 11
Claim · model-written summary
Chelated Fe applied to soil increased active Fe in soybean leaves by up to 42%.
- Taxon
- soybean
Glycine maxe1 - Organ / stage
- leavese1
- Treatment
- chelated Fe applied to the soil before sowinge1
- Outcome
- levels of active Fe (Fe2+) in leavese1
- Direction
- increasede1
- Value
- up to 42%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In soybean, chelated Fe applied to the soil before sowing increased the levels of active Fe (Fe2+) in leaves by up to 42% and dry matter of shoots by up to 46% early in the season”
Claim · model-written summary
Chelated Fe applied to soil increased shoot dry matter of soybean by up to 46% early in the season.
- Taxon
- soybeanGlycine maxe1
- Organ / stage
- shootse1
- Treatment
- chelated Fe applied to the soil before sowinge1
- Outcome
- dry matter of shootse1
- Direction
- increasede1
- Value
- up to 46%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In soybean, chelated Fe applied to the soil before sowing increased the levels of active Fe (Fe2+) in leaves by up to 42% and dry matter of shoots by up to 46% early in the season”
Claim · model-written summary
Active Fe and shoot dry matter of soybean were linearly correlated (r2 = 0.76).
- Taxon
- soybeanGlycine maxe1
- Organ / stage
- shootse2
- Outcome
- Active Fe and dry matter of shootse2
- Qualifier
- linearly correlated (r2 = 0.76)e2
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In soybean, chelated Fe applied to the soil before sowing increased the levels of active Fe (Fe2+) in leaves by up to 42% and dry matter of shoots by up to 46% early in the season”
e2“Active Fe and dry matter of shoots were linearly correlated (r2 = 0.76)”
Claim · model-written summary
Soil Fe treatments did not affect leaf photosynthesis in soybean.
- Taxon
- soybeanGlycine maxe1
- Treatment
- Soil Fe treatmentse3
- Outcome
- leaf photosynthesise3
- Direction
- did not affecte3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In soybean, chelated Fe applied to the soil before sowing increased the levels of active Fe (Fe2+) in leaves by up to 42% and dry matter of shoots by up to 46% early in the season”
e3“Soil Fe treatments did not affect leaf photosynthesis, although addition of chelated Fe to the soil resulted in greener leaves than in the control”
Claim · model-written summary
Addition of chelated Fe to soil resulted in greener soybean leaves than the control.
- Taxon
- soybeanGlycine maxe1
- Treatment
- addition of chelated Fe to the soile3
- Outcome
- leavese3
- Direction
- greenere3
- Comparator
- the controle3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In soybean, chelated Fe applied to the soil before sowing increased the levels of active Fe (Fe2+) in leaves by up to 42% and dry matter of shoots by up to 46% early in the season”
e3“Soil Fe treatments did not affect leaf photosynthesis, although addition of chelated Fe to the soil resulted in greener leaves than in the control”
Claim · model-written summary
Foliar Fe had no significant effect on active Fe, leaf colour or leaf photosynthesis in soybean.
- Taxon
- soybeanGlycine maxe1
- Treatment
- Foliar Fee4
- Outcome
- active Fe, leaf colour, or leaf photosynthesise4
- Direction
- no significant effecte4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In soybean, chelated Fe applied to the soil before sowing increased the levels of active Fe (Fe2+) in leaves by up to 42% and dry matter of shoots by up to 46% early in the season”
e4“Foliar Fe had no significant effect on active Fe, leaf colour, or leaf photosynthesis”
Claim · model-written summary
The 9% increase in soybean grain yield from 20 kg Fe ha-1 applied to soil was not significant.
- Taxon
- soybeanGlycine maxe5
- Treatment
- application of 20 kg Fe ha-1 to the soile6
- Outcome
- grain yielde6
- Direction
- increasee6
- Value
- 9%e6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“Experiments on soybean and pigeon pea grown on a Vertisol at Breeza, N.S.W., Australia”
e6“The 9% increase in grain yield in response to application of 20 kg Fe ha-1 to the soil was not significant”
Claim · model-written summary
Application of 20 kg Fe ha-1 to soil increased pigeon pea dry matter by 140%.
- Taxon
- pigeon pea
Cajanus cajane7 - Treatment
- application of 20 kg Fe ha-1 to the soile7
- Outcome
- dry mattere7
- Direction
- increasede7
- Value
- 140%e7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e7“In pigeon pea, application of 20 kg Fe ha-1 to the soil increased dry matter by 140% and grain yield by 414%”
Claim · model-written summary
Application of 20 kg Fe ha-1 to soil increased pigeon pea grain yield by 414%.
- Taxon
- pigeon peaCajanus cajane7
- Treatment
- application of 20 kg Fe ha-1 to the soile7
- Outcome
- grain yielde7
- Direction
- increasede7
- Value
- 414%e7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e7“In pigeon pea, application of 20 kg Fe ha-1 to the soil increased dry matter by 140% and grain yield by 414%”
Claim · model-written summary
Lime and zinc had no significant effect in pigeon pea.
- Taxon
- pigeon peaCajanus cajane7
- Treatment
- lime and zince0
- Direction
- not significante0
Not reportedComparatorOutcome
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e7“In pigeon pea, application of 20 kg Fe ha-1 to the soil increased dry matter by 140% and grain yield by 414%”
e0“Effects of lime and zinc were not significant, but N+P increased yield by 112%”
Claim · model-written summary
N+P increased pigeon pea yield by 112%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e7“In pigeon pea, application of 20 kg Fe ha-1 to the soil increased dry matter by 140% and grain yield by 414%”
e0“Effects of lime and zinc were not significant, but N+P increased yield by 112%”
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See all 36 papers →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.