42 kg/ha Granulock Z applied at sowing

Crop type: Sunflower (Hybrid: Ausigold 62). 

Starting soil water and moisture: 

The site was soil cored before sowing and found to have 103 mm of plant available water (PAW) to 1.2 m deep. A total of 284.5 mm of in-crop rainfall was recorded at the experiment site (Table 2). This was largely received as one large fall of over 50 mm in mid-November and another large fall of 68.5 mm in early January. The intensity of these summer storm events meant they were not as effective as they could have been if these volumes had been received over a more prolonged period.

TRIAL RESULTS: 

Plant height: 

Five plants in each plot were measured for height before harvest – from ground level up to the point of attachment at the back of the head. The average plant height in the experiment was 118.7 cm. The removal of all leaves at the budding stage resulted in plants with around half the height of those without leaves removed. No other treatment affected plant height.

Head diameter and arc length:

Five plants in each plot had head diameter and arc length measured before harvest. 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 9.1 cm, which illustrates the likely low grain yields from such a small-sized head.

There were significant treatment differences based on defoliation. The control, budding top 1/3, budding bottom 1/3 and start of flowering top 2/3 treatments had the largest head diameters. The total loss of leaves at the budding stage resulted in the smallest head diameter at 1.5 cm.

The average arc length was 12.1 cm and there were significant differences between defoliation treatments. Removing all leaves at budding had the largest impact on arc length, reducing it to 2.5 cm. The remaining defoliation treatments did not significantly affect arc length compared with the non-defoliated control.

Grain yield:

Yield was very low at this site in 2015–16, on average 0.24 t/ha. The coefficient of variation for grain yield was very high and, as such, no other grain yield data can be reported as the level of variability was too high.

Grain quality:

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 32.0 grams. The largest impact on grain weight was obtained by removing all leaves at budding or at the start of flowering, and removing the top 20 leaves at budding, which all had the lowest 1000 grain weights (data not shown). The average hectolitre weight in the experiment was 42.9 kg/hL, which is well above the receival standard of 32 kg/hL. The largest differences were between removing all leaves at budding, which had the high test weight of 46.4 kg/hL and removing the bottom 10 leaves at budding, which had the lowest test weight at 39.3 kg/hL (data not shown).

Crop type: Sunflower (Hybrid: Ausigold 62). 

Starting soil water and moisture: 

The site was soil cored before sowing and found to have 103 mm of plant available water (PAW) to 1.2 m deep. A total of 284.5 mm of in-crop rainfall was recorded at the experiment site (Table 2). This was largely received as one large fall of over 50 mm in mid-November and another large fall of 68.5 mm in early January. The intensity of these summer storm events meant they were not as effective as they could have been if these volumes had been received over a more prolonged period.

TRIAL RESULTS: 

Plant height: 

Five plants in each plot were measured for height before harvest – from ground level up to the point of attachment at the back of the head. The average plant height in the experiment was 118.7 cm. The removal of all leaves at the budding stage resulted in plants with around half the height of those without leaves removed. No other treatment affected plant height.

Head diameter and arc length:

Five plants in each plot had head diameter and arc length measured before harvest. 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 9.1 cm, which illustrates the likely low grain yields from such a small-sized head.

There were significant treatment differences based on defoliation. The control, budding top 1/3, budding bottom 1/3 and start of flowering top 2/3 treatments had the largest head diameters. The total loss of leaves at the budding stage resulted in the smallest head diameter at 1.5 cm.

The average arc length was 12.1 cm and there were significant differences between defoliation treatments. Removing all leaves at budding had the largest impact on arc length, reducing it to 2.5 cm. The remaining defoliation treatments did not significantly affect arc length compared with the non-defoliated control.

Grain yield:

Yield was very low at this site in 2015–16, on average 0.24 t/ha. The coefficient of variation for grain yield was very high and, as such, no other grain yield data can be reported as the level of variability was too high.

Grain quality:

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 32.0 grams. The largest impact on grain weight was obtained by removing all leaves at budding or at the start of flowering, and removing the top 20 leaves at budding, which all had the lowest 1000 grain weights (data not shown). The average hectolitre weight in the experiment was 42.9 kg/hL, which is well above the receival standard of 32 kg/hL. The largest differences were between removing all leaves at budding, which had the high test weight of 46.4 kg/hL and removing the bottom 10 leaves at budding, which had the lowest test weight at 39.3 kg/hL (data not shown).