The information contained in this publication is based on knowledge and understanding at the time of writing (July 2017) and may not be accurate, current or complete. The State of New South Wales (including the NSW Department of Industry), the author and the publisher take no responsibility, and will accept no liability, for the accuracy, currency, reliability or correctness of any information included in the document (including material provided by third parties). Readers should make their own inquiries and rely on their own advice when making decisions related to material contained in this publication. The product trade names in this publication are supplied on the understanding that no preference between equivalent products is intended and that the inclusion of a product name does not imply endorsement by the department over any equivalent product from another manufacturer.
Loretta Serafin, Mark Hellyer and Peter Perfrement (NSW DPI)
|Contributor||Department of Primary Industries NSW|
Site 3, Pine Ridge, NSW
|Further information||View external link|
To quantify the contribution of sunflower leaves to yield and oil quality through the application of twelve leaf defoliation treatments.
Sunflowers are generally considered a minor crop in the NSW northern grains region.
However, they play an important role in providing a broadleaf summer crop rotation option.
An individual sunflower plant produces on average between 2000–6,000 cm2 of leaf area, which drives yield and oil content.
Identifying which leaves contribute most towards yield and oil content helps growers make
decisions about disease, pest and general crop management in sunflower crops. Whether it is
because the crop is infected with a disease such as powdery mildew or has insect damage e.g.
loopers, the end result is a need for growers and advisors to know where and when to spend
money in crop protection to achieve the best economic return on investment of maintaining
green leaf area.
This experiment was one of three sunflower leaf-loss sites conducted in the 2015–16 season, with the other sites being located at Gurley and Willow Tree.
|Lead research organisation||
Department of Primary Industries NSW
|Host research organisation||N/A|
|Trial funding source||GRDC DAN00197|
|Trial funding source||DPI NSW DAN00197|
Tactical agronomy for selected crops in the northern region (safflower, linseed, sunflower)
This experiment was part of the project Tactical agronomy for selected crops in the northern region (safflower, linseed, sunflower) (DAN00197), with joint investment by NSW DPI and GRDC. Thanks to Nuseed and Neil Weier for the supply of experiment seed. Technical assistance provided by Delphi Ramsden (NSW DPI), Angus Hombsch, Alice Bowler and Bronwyn Brennan (formerly NSW DPI) is gratefully acknowledged. Thanks also to Neroli Graham, NSW DPI for assisting with data analysis. Thanks to Peter Winton, ‘Windy Station’, Pine Ridge for hosting the experiment.
|Other trial partners||Peter Winton, ‘Windy Station’, Pine Ridge|
|Crop type||Oilseed: Sunflower|
|Sow rate or Target density||Not specified|
|Sowing machinery||Not specified|
|Sow date||18 September 2015|
|Harvest date||17 February 2016|
|Plot size||Not specified|
|Plot replication||Not specified|
|Plot blocking||Not specified|
|Plot randomisation||Not specified|
|Paddock history||Not specified|
42 kg/ha Granulock Z applied at sowing
Defoliation applied prior to harvest
|Soil amelioration||Not specified|
|Seed treatment||Not specified|
|Other trial notes||
Crop type: Sunflower (Hybrid: Ausigold 62)
Starting soil water and rainfall
The site was soil cored before sowing and found to have 270 mm of plant available water (PAW) to 1.2 m deep. A total of 157.5 mm of in-crop rainfall was recorded at the experiment site
Five plants in each plot were measured for physiological maturity – taken from ground level up to the point of attachment at the back of the head. The average plant height in the experiment was 131.7 cm. No defoliation treatment affected plant height.
Head diameter and arc length:
Five plants in each plot had had head diameter and arc length measured at physiological maturity. Head diameter was measured across the back of the head and arc length across the front face of the head. The average head diameter was 14.1 cm. There were significant treatment differences based on defoliation . The smallest head diameters were recorded from removing all leaves at either budding or the start of flowering at 6.9 cm and 8.8 cm, respectively. There was very little difference statistically between many of the treatments.
The average arc length was 21.2 cm and there were significant differences based on the treatments. Removing all leaves at budding and the start of flowering had the largest impact on arc length reducing it to 9.7 cm and 16.2 cm respectively. The remaining defoliation treatments had no significant impact on arc length compared with the non-defoliated control
The average yield was quite low at the site in 2015–16 compared with that normally expected for sunflower crops on the Liverpool Plains, with an experiment average of 1.05 t/ha. There was, however, a large range in the yields as a result of the treatments. Removing the bottom 1/3 of leaves at budding had the highest yield at 2.07 t/ha, however, there was no significant difference in the top four yielding treatments. The lowest yields were obtained from the total leaf removal treatments at 0.16 t/ha.
Sub samples from each plot were collected at harvest and analysed for 1000 grain weight and test weight. Oil contents were not available at the time of publication.
The average 1000 grain weight in the experiment was 47.1 grams. The largest effects on grain weights were obtained in treatments were all leaves were removed, while the smallest impact on grain weight was obtained when only the top 10 leaves were removed (data not shown).
The average hectolitre weight in the experiment was 39.2 kg/hL, which is well above the receival standard of 32 kg/hL. The largest reduction in test weight resulted from removing all leaves at the end of flowering (data not shown).
||Plant height (cm)||Head arc length (cm)||Head diameter (cm)|
|1||█ Control - no leaves removed (0/3)||130.6||23.5||16.3|
|2||█ Budding - remove all leaves (3/3)||121.7||9.7||6.9|
|3||█ Budding - remove top 10 leaves (1/3)||132.1||24.1||17.7|
|4||█ Budding - remove top 20 leaves (2/3)||133.5||18.8||13.1|
|5||█ Budding - remove bottom 10 leaves (1/3)||136.5||24.3||15.7|
|6||█ Start of flowering - remove top 10 leaves (1/3)||135.1||24.5||17.1|
|7||█ Start of flowering - remove top 20 leaves (2/3)||128.7||19||15.6|
|8||█ Start of flowering - remove all leaves (3/3)||128.7||16.2||8.8|
|9||█ Start of flowering - remove bottom 10 leaves (1/3)||136.1||25.7||17.1|
|10||█ Flowering complete - remove top 10 leaves (1/3)||134.3||24.3||16.1|
|11||█ Flowering complete - remove top 20 leaves (2/3)||134||22.1||15.1|
|12||█ Flowering complete - remove all leaves (3/3)||129.1||22.5||13.1|
|LSD||(P=0.05): n.s.||(P=0.05): 4.11||(P=0.05): 3.88|
|Rainfall avg ann (mm)||668.9mm|
|Rainfall trial gsr (mm)||157mm|
SILO weather estimates sourced from https://www.longpaddock.qld.gov.au/silo/
Jeffrey, S.J., Carter, J.O., Moodie, K.B. and Beswick, A.R. (2001). Using spatial interpolation to construct a comprehensive archive of Australian climate data , Environmental Modelling and Software, Vol 16/4, pp 309-330. DOI: 10.1016/S1364-8152(01)00008-1.