Article taken from The Scottish Farmer, edited by Ken Fletcher
Trials of oilseed rape from near Brechin and now harvested could help shed light on decision-making processes for next year’s crop.
Agrovista’s Grow Crop Gold trials site, at Southesk Farms, Brechin, is managed by Neil Macleod and has seen some exceptional yields, said the company’s local man on the ground, Grant Reid.
Investigations into variable seed and fertiliser rates, cultivation practices and companion planting have thrown up some interesting stats. “We’ve had 12 trial plots of the variety Harper, which was sown straight into stubble on August 22 last year and cultivated using either the Great Plains Simba STX or the Vaderstad Spirit Strip Tiller,” explained Mr Reid.
“The plots were harvested on August 5 this year and yields ranged from an equivalent of 5.17t/ha up to 6t/ha, and were probably so high because oilseed rape crops did not stop growing over the autumn and winter months.”
He added: “Fewer plants per row – determined by row widths and seed rate – resulted in higher yields because plants were allowed to develop more branching, more pods and more seeds per pod.” They were sown at row widths of 550mm and 334 mm and at seed rates as low as 7.5 seeds per m row length.
The highest yielding plot was sown at 15 seeds per m row length (45 seed /m²) and at a row spacing of 334mm.
“This is consistent with other Agrovista Grow Crop Gold trials, our results have shown that even rates of 45 seeds/m² are too high and that growers could reduce rates to as low as 25-30 seeds to achieve this all-important branching.”
“Low plant numbers at Southesk created what we would expect – visibly different, open crop canopies with many more side branches,” he said. “The plants had larger stem circumferences, were slightly taller and retained more green leaf area.”
He suggested that plants also took advantage of getting the extra fertiliser available to them due to lower population and wider, more open canopies allowed light to penetrate through to the leaves.
On another point, he noted from trials where nitrogen was placed in the seedbed at sowing, the plants were slightly further ahead of other plots throughout the growing season. “This is worth growers doing if a crop is being sown later than ideal,” he advised.
Companion crops were also studied to determine yield and soil structure improvements. Mixes of berseem clover, purple vetch and common vetch were sown in some of the Southesk oilseed rape plots at rates of 10kg/ha and 20kg/ha, and Mr Reid said that there was no yield advantage for the crop at the site – however, the trend at our other trial sites this year has been a crop yield benefit.”
There was a marked improvement in soil structure as a result of berseem clover acting as a ‘pan buster’ to break up any compacted areas in the soil profile. “There is also perceived benefits of companion plants helping to reduce flea beetle damage to OSR plants and now that the neonic restrictions are in place we will monitor the effect with great interest this coming season,” he added.
Trials of oilseed rape from near Brechin and now harvested could help shed light on decision-making processes for next year’s crop.
Agrovista’s Grow Crop Gold trials site, at Southesk Farms, Brechin, is managed by Neil Macleod and has seen some exceptional yields, said the company’s local man on the ground, Grant Reid.
Investigations into variable seed and fertiliser rates, cultivation practices and companion planting have thrown up some interesting stats. “We’ve had 12 trial plots of the variety Harper, which was sown straight into stubble on August 22 last year and cultivated using either the Great Plains Simba STX or the Vaderstad Spirit Strip Tiller,” explained Mr Reid.
“The plots were harvested on August 5 this year and yields ranged from an equivalent of 5.17t/ha up to 6t/ha, and were probably so high because oilseed rape crops did not stop growing over the autumn and winter months.”
He added: “Fewer plants per row – determined by row widths and seed rate – resulted in higher yields because plants were allowed to develop more branching, more pods and more seeds per pod.” They were sown at row widths of 550mm and 334 mm and at seed rates as low as 7.5 seeds per m row length.
The highest yielding plot was sown at 15 seeds per m row length (45 seed /m²) and at a row spacing of 334mm.
“This is consistent with other Agrovista Grow Crop Gold trials, our results have shown that even rates of 45 seeds/m² are too high and that growers could reduce rates to as low as 25-30 seeds to achieve this all-important branching.”
“Low plant numbers at Southesk created what we would expect – visibly different, open crop canopies with many more side branches,” he said. “The plants had larger stem circumferences, were slightly taller and retained more green leaf area.”
He suggested that plants also took advantage of getting the extra fertiliser available to them due to lower population and wider, more open canopies allowed light to penetrate through to the leaves.
On another point, he noted from trials where nitrogen was placed in the seedbed at sowing, the plants were slightly further ahead of other plots throughout the growing season. “This is worth growers doing if a crop is being sown later than ideal,” he advised.
Companion crops were also studied to determine yield and soil structure improvements. Mixes of berseem clover, purple vetch and common vetch were sown in some of the Southesk oilseed rape plots at rates of 10kg/ha and 20kg/ha, and Mr Reid said that there was no yield advantage for the crop at the site – however, the trend at our other trial sites this year has been a crop yield benefit.”
There was a marked improvement in soil structure as a result of berseem clover acting as a ‘pan buster’ to break up any compacted areas in the soil profile. “There is also perceived benefits of companion plants helping to reduce flea beetle damage to OSR plants and now that the neonic restrictions are in place we will monitor the effect with great interest this coming season,” he added.