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ESTABLISHMENT TECHNIQUES.

Seedbed.
Rape requires a fine tilth with good soil to seed contact. Unless there are overriding circumstances such as soil compaction or perhaps a risk of herbicide residues from a previous crop, then the minimum amount of work put into the seedbed to achieve a fine tilth should be aimed for.

Autocasting.
This operation is only suitable where there is some surface tilth and no soil compaction. It is suitable for those soils that produce good surface tilths. Avoid compacted soil surface. Ideally use after a later maturing wheat variety and sow mid-august. Avoid using this method if previous crops have had a high diflufenican or sulphonyl-urea doses. Leave 20-30cm stubble and spread straw and chaff evenly. Roll as soon as possible after seeding and treat with slug pellets. As with all operations where there are high levels of previous crop residues you will need to continue to monitor for slug damage and treat accordingly. With this type of operation you will need to monitor volunteer development and treat where necessary. Broadleaved weed numbers should generally be lower than where full tillage has been carried out and in many cases only thistle and cleavers will be a problem. In a wet autumn you may well see broadleaf weed emergence requiring a post-emergence weedkiller. It would be wise to apply nitrogen to the seedbed - an application of 30kg/ha would suffice.

Direct drill or scratch cultivate.
This is a less risky method of establishment than autocasting but will still be prone to slug attack and flushes of volunteers.

Non-inversion tillage.
If soil compaction is seen near the surface, or there is no surface tilth, then this type of tillage where some soil mixing takes place may suit the situation. Roll immediately after this operation to conserve moisture. The mechanics of this method will help reduce slug populations. With movement of soil, weed germination will be greater so it is likely a pre-emergence herbicide will be required.

Ploughing systems.
This is an operation still done by many but must only be considered as a last resort for soils requiring some restructuring. This operation is prone to massive moisture loss and requires expensive secondary cultivations, often with more than one operation to achieve a seedbed, although slug numbers are reduced - particularly if the soil is well consolidated. You will definitely require a pre-emergence weedkiller with this system, however, volunteer flushes will be slower than where shallow cultivation methods are used.

It may be worth mentioning at this point a new system that have come to the market for drilling oilseed rape.

The Claydon Drill - 'The principle'.
This is a direct drill that can be used for drilling into stubble, min-till or fully cultivated land. Firstly the Claydon Drill ruptures the soil with a rigid front tine. This creates shatter in the soil for plant roots to grow down and for water to drain through, creating ideal conditions for germination and a good environment for the crop. This tine is adjustable from 1.5" to 6" below the seed depth. All processes are conducted in line for maximum versatility and efficiency.
The second process is conducted by an A-Hoe tine. This lifts the soil creating a tilth. The larger lumps of soil and the straw are combed to the side of the A-Hoes and left in bands. The finer tilth is dropped over the back of the A-Hoe, on top of the seed injected by the spreading boot. This spreads the seed into 6" bands under the A-Hoe. Each seed band has its own press wheel that is used to gently firm the soil providing a good soil to seed contact.
We have used this drill for the last two seasons for drilling oilseed rape and we are very impressed with establishment behind it. Rape certainly gets away well, looks very green (less effect from straw toxins), although slugs, as with any min-till system, need to be continually monitored. Treating after drilling is a must.
(For more information contact Geoff Claydon 01440 820327).

Cost analysis of various establishment techniques.

OSR DRILLING COST ANALYSIS BY SYSTEM.

System	Operation	Output Ha/Hour	Labour Minutes/Ha	Costs/Ha
Conventional	5 Furrow Plough & Press	0.87	69.00	£36.00
	Power Harrow	1.50	40.00	£23.25
	(Power Harrow)	1.50	(40.00)	(£23.25)
	(Cambridge Rolls)	2.75	(22.00)	(£10.25)
	Drill	2.00	30.00	£16.00
	Cambridge Rolls	2.75	22.00	£10.25
	Totals for conventional system		161-223 Mins/Ha	£95.75-£119.00/Ha
Minimal Till	Mulch Tiller (Twice)	3.24	37.00	£35.00
	Cambridge Roll/Press	2.75	22.00	£10.75
	Spraying	5.60	10.70	£7.00
	8m Drill	4.80	12.50	£22.00
	(Cambridge Rolls)	2.75	(22.00)	(£10.25)
	Totals for minimal till system		64-104 Mins/Ha	£56.75-£84.50/Ha
Direct Drill	Spraying	5.60	10.70	£7.00
	Claydon Drill	4.00	15.00	£25.00
	(Cambridge Rolls)	2.75	(22.00)	(£10.25)
	Totals for direct drill system		25.70 - 48 Mins/Ha	£32.00 - £42.00/Ha

Latest sowing date.
The latest safe sowing date for rape varies with location. However, the end of September is a useful guideline. Crops drilled after this date could be slow to develop. As a rule, rape plants need a minimum of 2-3 true leaves to overwinter. For patching crops we would suggest the end of October is the very latest safe cut off date.

• Sowing depth needs to be uniform and to a depth of 12-20 mm, preferably into soil moisture to provide rapid emergence and maximum seed vigour.
• Seedbeds must be firm and clod free to enable good contact between seed and soil.
• Excessive speed of drilling will lead to coulter bounce and uneven drilling.
• The need to roll if conditions allow after drilling is paramount, as moisture retention in the seedbed is essential to good germination.
• If you decide to broadcast, harrow and roll after this operation to establish soil contact with seed and retain moisture.
• If canopy in winter is to thick, consider mowing or applying spring fungicide with regulating properties.

• Take account of seedbed tilth, moisture and winter plant losses in determining seed rate.
• Adjust sowing date and seed rate to influence canopy size, do not sow to early.
• Control slugs and pigeons if low seed rate used.
• Assess fertiliser N needed in early spring on the basis of soil mineral nitrogen

SEED RATES.
We believe this is the single most important factor in determining the overall yield. With regard to the main conventional varieties we would suggest an optimum density of 100 seed/sqm. on heavy and medium land. In the case of Winner we would suggest 90 plants/sqm in view of its lodging characteristics. 50-60 plants /sqm after winter is what we are aiming for. Please delay drillings on light land until 1st week of September onwards or towards the end of the drilling programme on a range of soil types. For hybrid varieties, aim for target populations of 35-45 plants/sqm.in the spring

When calculating seed rates a number of factors must be taken into account.

Thousand grain weight. This is the weight in grammes of 1000 grains from your seed lot and is used to quantify by weight the number of seeds per square metre required.
% Establishment. This is affected by date of sowing, seedbed conditions, seed vigour and drainage. For future reference it is useful to check the accuracy of this figure in the field by carrying out plant counts.

% Establishment	=	Plants established/sqm X 100
		Seeds sown/sqm

Seed Rate	=	Target population (eg.90 x TGWgms)
		% Establishment expected

Example.
TGW = 5gm, target population 80, % germination 99, % establishment 75%.

Seed rate (kg/ha)	=	5(TWGgms) x 80(plants per sqm) x 100	=	40000	=	5.38kg/ha
		99(%germination) x 75(%establishment)		7425

Farm Saved Seed - seed size and quality
Results from work carried out over the last few seasons on the comparison between small, medium and large seed, has indicated that large seed was faster to establish and more vigorous than small seed. Care needs to be taken at harvest to achieve the required seed quality.
The practical implications:

Crop Failure Threshold.
If damage or plant loss occurs in winter oilseed rape it must be remembered that this crop does have tremendous powers of recovery. If a crop has had its stand reduced to 20-30 plants /sqm this will produce comparable yields to a crop having 70-80 plants/sqm, providing these remaining plants are evenly distributed. The decision to plough a crop in needs to be delayed until the last minute. A crop of 9-10 plants /sqm will produce acceptable yields if the plants are strong, healthy and evenly distributed. A crop in early March can look a lot different to a crop in early January or February. This decision must be made before you apply the first spring nitrogen dressing. A further factor that will need to be taken into account, when considering whether to plough a crop in, will be what weedkillers has been applied to this crop earlier in the season. Previous weedkiller usage will influence what crop can be drilled, along with the method of crop establishment.

PHYSICAL DISORDERS
Hail Damage.
Leaf damage
Leaves damaged by hail show whitish discolourations, cracks, holes and breakages. Often the whole leaf can be knocked off.

Stem damage.
Cells in the epidermal layer are crushed and damaged and this produces grey-white flecks on the stem itself. Damaged stems will often bend over and show open wounds. These can recover but stems with more than half of their diameter damaged can be completely lost.

Buds/flowers/pods etc.
These can often be knocked off or broken by hailstones. At the end of flowering the plant is not able to compensate for this damage and so losses will be severe. Hail on immature pods will not cause pod shatter but seeds at the point of contact will be stunted and small often giving the opening for oviposition of brassica pod midge. On mature pods hail damage can cause pod shattering and seed loss.

Precautions.
Desiccate with glyphosate. This helps to leave pods a little more supple than where desiccated with Diquat and so a little less prone to shattering. If you are in an area that sees hail storms on a regular basis you may be wise to take out hail insurance.

Growth Splits
Growth splits will be often seen on the stems of rape if heavy rain occurs after a long period of dry weather. These splits soon heal, however, if they occur when spores of stem canker are about this can lead to secondary infection.

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ALL INFORMATION INCLUDED ON THESE PAGES IS FOR GUIDANCE ONLY & DOES NOT CONSTITUTE RECOMMENDATION FROM AGRIVICE LTD