Abstract
The initial growth of wheat crops can be manipulated either by agronomic means, such as by increasing inputs of seed and fertiliser, or by genetic improvement in early vigour. Cultivars of wheat with enhanced early vigour are still not commercially available and so a series of experiments was conducted to examine the impact of increasing initial dry matter production and leaf area index by increasing sowing and nitrogen (N) rates on grain yield. Increasing the sowing rate and amount of N fertiliser applied significantly increased early dry matter production and leaf area, with the largest responses occurring when sowing rate was increased. However, there was little effect on yield. The increases in dry matter production that occurred early in the season as a result of the additional inputs diminished as the season progressed. Yield responses to the additional inputs depended on the seasonal distribution of rainfall and in particular the rainfall received in August and September when grains per m2 were being determined. Consequently, yield responses were affected more by changes in grain per m2 than by changes in grain weight, and the benefits of the improvements in early vigour were only realised when moisture availability was high during the immediate pre-anthesis and early grain filling period of growth. High rainfall in August and September increased the responses in grains per m2 from increased sowing rate and N. When N was used to increase early growth, the response in grain weight was negatively correlated with increasing pre-anthesis rainfall, but there was no relationship with rainfall when sowing rate was used to increase early growth. This effect of N, in which responses in pre-anthesis growth were offset by reductions in grain weight, is consistent with the ‘haying-off’ effect that can occur with applications of N. The results showed that increasing early vigour by increased inputs of seed and N fertiliser produce variable responses in grain yield. While improvements in vegetative growth occurred, the realisation of these gains only happened when rainfall in August and September was adequate. Basing improvements in early vigour only on agronomic manipulation appears to be associated with a relatively high level of risk, as it is difficult to control the balance between vegetative growth and the availability of soil moisture. Alternatively, the data suggest that the levels of early vigour under current agronomic practices may be adequate (>50 g/m2 shoot DM at late tillering stage), and only marginal gains may be achieved by promoting early growth by additional inputs.
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Claims 11
Claim · model-written summary
Increasing the sowing rate significantly increased early dry matter production and leaf area in wheat, with the largest responses at higher sowing rate.
- Taxon
- wheat
Triticum aestivumt0 - Treatment
- Increasing the sowing ratee1
- Outcome
- early dry matter production and leaf areae1
- Direction
- significantly increasede1
- Qualifier
- with the largest responses occurring when sowing rate was increasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“early vigour in wheat on growth and yield in South Australia”
e1“Increasing the sowing rate and amount of N fertiliser applied significantly increased early dry matter production and leaf area, with the largest responses occurring when sowing rate was increased”
Claim · model-written summary
Increasing the amount of N fertiliser applied significantly increased early dry matter production and leaf area in wheat.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- amount of N fertiliser appliede1
- Outcome
- early dry matter production and leaf areae1
- Direction
- significantly increasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“early vigour in wheat on growth and yield in South Australia”
e1“Increasing the sowing rate and amount of N fertiliser applied significantly increased early dry matter production and leaf area, with the largest responses occurring when sowing rate was increased”
Claim · model-written summary
Increasing sowing rate and N fertiliser had little effect on wheat yield.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- Increasing the sowing rate and amount of N fertiliser appliede1
- Outcome
- yielde2
- Direction
- little effecte2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“early vigour in wheat on growth and yield in South Australia”
e1“Increasing the sowing rate and amount of N fertiliser applied significantly increased early dry matter production and leaf area, with the largest responses occurring when sowing rate was increased”
e2“However, there was little effect on yield”
Claim · model-written summary
The early increases in dry matter production from additional inputs diminished as the season progressed.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- additional inputse3
- Outcome
- increases in dry matter productione3
- Direction
- diminishede3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“early vigour in wheat on growth and yield in South Australia”
e3“The increases in dry matter production that occurred early in the season as a result of the additional inputs diminished as the season progressed”
Claim · model-written summary
Yield responses to additional inputs in wheat depended on the seasonal distribution of rainfall, especially rainfall in August and September.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- additional inputse4
- Outcome
- yield responsese4
- Setting
- seasonal distribution of rainfalle4
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“early vigour in wheat on growth and yield in South Australia”
e4“Yield responses to the additional inputs depended on the seasonal distribution of rainfall and in particular the rainfall received in August and September when grains per m2 were being determined”
Claim · model-written summary
High rainfall in August and September increased the responses in grains per m2 from increased sowing rate and N in wheat.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- increased sowing rate and Ne6
- Outcome
- responses in grains per m2e6
- Direction
- increasede6
- Setting
- High rainfall in August and Septembere6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“early vigour in wheat on growth and yield in South Australia”
e6“High rainfall in August and September increased the responses in grains per m2 from increased sowing rate and N”
Claim · model-written summary
When N was used to increase early growth, the response in grain weight was negatively correlated with pre-anthesis rainfall.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- used to increase early growthe7
- Outcome
- response in grain weighte7
- Direction
- negatively correlatede7
- Setting
- pre-anthesis rainfalle7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“early vigour in wheat on growth and yield in South Australia”
e7“When N was used to increase early growth, the response in grain weight was negatively correlated with increasing pre-anthesis rainfall, but there was no relationship with rainfall when sowing rate was used to increase early growth”
Claim · model-written summary
When sowing rate was used to increase early growth, grain weight showed no relationship with rainfall.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- sowing rate was used to increase early growthe7
- Outcome
- grain weighte7
- Direction
- no relationshipe7
- Setting
- rainfalle7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“early vigour in wheat on growth and yield in South Australia”
e7“When N was used to increase early growth, the response in grain weight was negatively correlated with increasing pre-anthesis rainfall, but there was no relationship with rainfall when sowing rate was used to increase early growth”
Claim · model-written summary
Increasing early vigour by additional seed and N inputs gave variable grain yield responses in wheat.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- increasing early vigour by increased inputs of seed and N fertilisere0
- Outcome
- grain yielde0
- Direction
- variable responsese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“early vigour in wheat on growth and yield in South Australia”
e0“The results showed that increasing early vigour by increased inputs of seed and N fertiliser produce variable responses in grain yield”
Claim · model-written summary
The authors state that basing early-vigour improvements only on agronomic manipulation carries a relatively high level of risk in wheat.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- Basing improvements in early vigour only on agronomic manipulatione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“early vigour in wheat on growth and yield in South Australia”
e1“Basing improvements in early vigour only on agronomic manipulation appears to be associated with a relatively high level of risk”
Claim · model-written summary
The authors suggest that current early vigour in wheat may be adequate, with only marginal gains from additional inputs.
- Taxon
- wheatTriticum aestivumt0
- Organ / stage
- late tillering stagee2
- Outcome
- marginal gains may be achieved by promoting early growth by additional inputse2
- Value
- >50 g/m2e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“early vigour in wheat on growth and yield in South Australia”
e2“the levels of early vigour under current agronomic practices may be adequate (>50 g/m2 shoot DM at late tillering stage), and only marginal gains may be achieved by promoting early growth by additional inputs”
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See all 3,438 papers →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.