Spring and Winter Canola: Harvest and Storage

Excerpt from Agronomy Guide for Field Crops (Chapter 8)

Order OMAFRA Publication 811: Agronomy Guide for Field Crops

Table of Contents

1. Introduction
2. Direct Harvest
3. Swathing
• Combining Canola Swaths
4. Storage
5. Updates on Spring and Winter Canola: Harvest and Storage

Introduction

The most common method of harvesting canola is swathing, followed by combining, but direct harvest is also used.

Direct Harvest

Direct combining is most successful when the crop's maturity and crop density are uniform, and the crop is relatively heavy, partially lodged and well knitted together. These conditions reduce the risk of shelling and pod drop due to wind. For direct-harvested canola, the crop is ripe when the pods rattle when shaken. Some varieties are less prone to shattering and are therefore well suited to direct combining. The need for and cost of using a desiccant should be evaluated versus swathing the crop. Seed oil content tends to be higher when a crop is direct harvested.

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Swathing

Swathing at the correct stage of maturity reduces green seed and seed losses from shattering. The colour of the seed is more important than the overall colour of the field. When the seed reaches physiological maturity at 35%-40% moisture, it turns from green to yellow and then to a dark brown. The time to swath is when most of the yield in a field is ready. The optimum time to swath is when 30%-40% of the seeds in pods on the main stem have changed to red or brown.

The pods at the bottom of a canola plant ripen first, therefore the pods at top may still be greenish when the field is ready for harvest. Yield losses and quality reductions (lower oil content and green seeds) are significant if the crop is swathed prior to 10% seed colour change. Later swathing can result in excessive shattering of the seedpods. On larger acreage, if swathing is started at 25% colour change, then the majority of acres can be swathed at near optimum maturity. Seed colour can quickly go from 10% to near 50% in a few days, under hot, dry weather.

Under hot (30°C or 86°F), dry conditions, swathing is not recommended. Swathing in the morning or evening results in slower plant dry-down. This lowers the chance of green seed and poor oil content.

Canola ripens and dries quickly in the swath. Usually 5-10 days of good drying weather will lower the moisture content to a point where the seeds in the upper pods of the plants are firm. Canola seed can drop by 1% moisture or more per hour in the swath. Many operators start combining when the seed is slightly above 10% moisture.

Swathing canola can be achieved using an open-throated swather. It often helps to swath when the crop is moist with dew or during a light drizzle. The stubble should be left tall enough to support the swath (and minimize combine wear) but cut low enough to leave stems on the plants for filling purposes.

Late in the season, if frost is forecasted and plants are not at optimum maturity, swathing at 10% seed colour change will minimize green seeds as a result of the frost. A field that has been swathed 3 days prior to a frost will have minimal damage.

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Combining Canola Swaths

Seed moisture content and green seed count should be checked before starting to combine. Hot or windy weather can result in seed with moisture that indicates it is ready for combining, before it has had sufficient time to clear itself of green chlorophyll. Several dews or light rain help seed to clear the green colour. Under good drying conditions, moisture content drops rapidly and combining can begin at about 12% moisture. Most current combine manuals include instructions for canola. A belt pick-up is preferred. Wind adjustment is critical. Use just enough wind to float the straw and pods on the chaffer and shake the seeds out of the straw. On larger-capacity combines, running the combine full with partial wind and sieve openings allows more rapid travel. Good combine set-up will allow some pod-ends to come into the bin. A very clean sample likely means seed is being blown out the back of the combine.

Storage

Canola seed is sold on the basis of 10.5% moisture, but for safe storage it should be less than 10% moisture. The moisture level for storage depends on temperature. At 30°C (86°F), seed should be no more than 8% moisture. Because the seed is small, air does not easily move through large quantities of canola. If the seed is tough or damp, spread it out in shallow layers and check frequently for heating. Canola can also be dried in a grain drier using low temperatures, but fine screens are necessary to prevent leakage.

Updates on Spring and Winter Canola: Harvest and Storage

No updates available at this time.

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Related Links

• Canola