Agronomist - Summer 2007
Crop knowledge key to machine’s development.
A new crop establishment system has been developed with advice from an agronomist and extensive trialling on a number of farms.
Machinery specialist OPICO launched it’s Till-Seeding concept two years ago and it now consists of three systems for drilling oilseed rape and one for cereals.
The technique was developed in conjunction with Phillip Marr, a Yorkshire-based agronomist with Masstock Arable.
He outlined the challenge facing oilseed rape growers in particular of being able to establish the crop with a good root structure and that soil structure is vital.
“Oilseed rape is such a lazy rooting crop that it actually needs a close open channel to put its root down,” says Mr Marr. “It struggles with any compaction or even a solid layer in the soil.”
He adds that root development is the plant’s main preoccupation in the autumn when 80% of total root growth takes place.
In the winter, a well-rooted rape plant is able to access the nutrients it needs, while good soil structure reduces the chances of water-logging. When spring comes, the better-established plant can start to grow as soon as the weather warms up, allowing it to utilise soil nitrogen and develop a large green leaf area. In summer, deep roots will access water in dry conditions and make full use of nutrients.
But successful rape crops are not just ones that are allowed to grow downwards, they also need space to grow sideways.
Mr Marr reminds growers and advisers that rape seedlings exude chemicals that are toxic to their neighbours, so proper spacing is important.
“Around 60% of the yield in rape comes from the lateral branches, while the crown provides the smallest seeds,” says Mr Marr.
“The lower pods have the greatest yield potential as they can produce the largest seeds, increasing hectolitre weight and overall yield. Lower pods are likely to abort seed if they do not receive enough sunlight to photosynthesise and nutrients to develop. So, spatial arrangement and seed rates are critical in a rape crop.”
Masstock trials show that a much reduced seed rate will mean stronger and higher yielding plants will be retained in spring. The company found that at a seed rate of 160 seeds per metre squared there was a 43% plant loss in the spring. At 120 seeds/m2 the plant loss was 33% and at 40 seeds/m2 the loss was just 22%
Using this knowledge, OPICO set about designing a system that would place seeds into a well-structured seedbed at a consistent depth and width.
James Woolway, Managing Director of the company, says the aim was to get a system that gave the crops a good start with the minimum of tillage.
“Besides saving costs, fewer passes helps conserve soil moisture and there is less activation of volunteer rape and weed seeds, particularly blackgrass.”
What has emerged is three machines designed to suit a variety of growing conditions. The first (Subsoiler Till-Seeding) for lighter land consists of a subsoiler leg that creates a clean friable tilth into which a seeder places the seed with a following ‘V’ roller consolidation the soil.
A second system (Combination Till-seeding) is for heavier land, where a disc roller follows the subsoiler, creating a tilth before seed is placed in the ground and followed by a compacting ‘V’
Roller.
The third option is for freer draining soil where there is no need to use a subsoiler. There is a choice of a tine or disc option. The tine cultivates the soil to a depth of up to 150 millimetres and then the seed is broadcast or placed in the soil in front of a ‘T’ profile roller. The disc option incorporates a soil mat to prevent soil from affecting the distribution of the seed. Instead of the ‘T’ roller a ‘V’ roller is used.
The three systems use the Variocast seed metering unit. There are two versions: The Variocast 8 which uses a mechanical land-wheel and flexible cable stepless gearbox system to meter out the seed, and the Variocast 8E, which uses a pulse wheel sensor to ensure that seed flows at a consistent rate regardless of how much seed is in the hopper.
The lessons learnt on the oilseed rape Till-Seeding systems have been translated into a cereal drill called the Sabre Seeder.
“A single pass operation means saving time, fuel and machinery wear, creating a smaller carbon footprint when producing crops,” says Mr Woolway.
“Reducing all of these costs will become increasingly important when competing in a global market.”
For drilling into uncultivated land, the Sabre seeder can be fitted with tines, which are followed by a disc coulter that opens up the soil allowing the seed to be placed at a consistent depth. This is then followed by consolidating rollers.
For more details on the HE-VA Sabre Seeder Grain Drill click here.. |
