OMAFRA Field Crop Report

Table of Contents

• Forage Report
• Corn
• Soybeans
• Edible Beans
• Canola
• Winter Cereals
• Spring Cereals

For emerging issues, questions or to provide feedback on this report, contact the CropLine at 1-888-449-0937. Technical information can also be obtained at the OMAFRA Field Crops Webpage at www.ontario.ca/crops and Crop Pest Ontario at www.omafra.gov.on.ca/croppest . Referenced OMAFRA Publications include the new edition of Publication 811 Agronomy Guide for Field Crops, 812 Field Crop Protection Guide, 75 Guide to Weed Control, and 505 Ontario Weeds. These can be obtained from your OMAFRA Resource Centre, or by calling 1-800-668-9938.

Forage Report

With the sunny weather this September, it has been very tempting to cut some forage for haylage or baleage. In order to reduce the risk of alfalfa winterkill, it is generally recommended that alfalfa not be cut during the Critical Fall Harvest Period. This is the 6 week period before the average date of killing frost. This allows a harvested alfalfa plant to regrow and store sufficient root reserves to survive the winter. Early in the period the alfalfa will use the existing root reserves for regrowth, "emptying the tank". Later in the period, the alfalfa stores photosynthesis produced carbohydrates as root reserves, "refilling the tank". Cutting in the middle of the Critical Period is usually higher risk than cutting at the beginning or the end. Even when winterkill does not occur, loss of vigour and yield the following spring typically results. Research shows that the yield sacrificed by not harvesting during the Critical Fall Harvest Period is usually regained in first-cut yield the following year. The decision to cut should be weighed against the immediate need for forage.

Sufficient top growth is required to hold snow that helps insulate overwintering crowns against cold temperature damage and frost heaving. Older stands with less disease resistance, low potassium soil tests, poor varieties and poor soil drainage are all at increased risk of winterkill. Aggressive cutting schedules with cutting intervals of less than 30 days between cuts increases the risk of winterkill, while intervals over 40 days (allowing flowering), reduces the risk. Refer to OMAFRA Factsheet 91-072 "Alfalfa Winterkill Risk Factors".

Risk can be reduced, but not eliminated, by cutting towards the end of alfalfa growth, close to a killing frost. A killing frost occurs when temperatures reach -4°C for several hours. After a killing frost, alfalfa's feed value will decline, as leaf loss occurs and rain leaches nutrients quickly. Leaving at least 6 inches of stubble will help trap snow to insulate the alfalfa crowns during cold weather. Stubble will also protrude through winter ice sheeting, should that occur.

Heavy stands of grasses or red clover left unharvested can sometimes smother over the winter because the top growth forms a dense mat. In contrast, alfalfa loses most of its leaves as soon as there is a hard frost, and the remaining stems seldom pose any risk of smothering.

Corn

The first 14 days of September have been kind to the corn crop. Night-time temperatures were quite favourable for grain fill and some areas came close to or exceeded 300 CHU in the first two weeks; about 10% above normal. Early planted corn is on track to reach maturity in the last week of September, later planted corn may need an additional two weeks depending on the hybrid and local climatic conditions.

A killing frost (stems and leaves) that occurs at the one-half milk line will reduce yields by about 10%, alternatively a killing frost at the early dent stage will reduce yields by approximately 25%.

Crop health remains strong in most of the province, with the exception of some areas which are very dry. Some concern is being expressed about the poor ear tip fill in many fields, especially under delayed planting. A range of conditions can lead to poor tip fill. This year it appears that it may be caused by the relatively large number of kernels that were successfully pollinated. This combined with the start of grain filling being pushed back into August means that the photosynthetic engine may simply be not getting the day length, temperatures or sunlight intensity required to manufacture enough starch to fill all the kernels on the ear. Yields may still be quite respectable in these fields.

Silage harvest is just beginning in some areas. Be sure to monitor whole plant moistures. Milk line targets (i.e. one-half to two-thirds) are reasonable tools to estimate silage moisture; however data over many years show a range in whole plant moisture at one-half milk line of 52%-72%, with an average of 63%. These moistures will be too wet for some and much too dry for others. The two most significant causes of moisture variation are weather and hybrid differences.

The recommendation is to determine whole plant moisture shortly after denting when the milk line is about 20%. Experience shows that in a typical year, corn silage at this stage dries approximately 0.5% per day. Therefore, if the sample was 70% moisture, and 65% moisture is the target, harvest should occur about 10 days after the corn was sampled. Be aware, however, that the dry, relatively warm conditions in September can result in silage moistures dropping much more quickly than 0.5% per day.

Soybeans

The past three weeks of warm dry weather have improved the outlook of many soybean fields in the province. Soybeans are now changing colour and a few early planted fields have already been harvested. Most fields are now in the R7 (beginning maturity) - R8 (full maturity) stage. Yields are expected to range tremendously this year depending on soil type, drainage, planting date, and aphid levels. Much of the province is expected to have an average to slightly below average crop. Weather permitting, harvest will start in earnest over the next 7-14 days.

Some fields, depending on planting date, variety, and region, were hit with white mould this year. Take note of which fields have white mould pressure this year to aid in planning for future soybean crops. Foliar fungicide sprays have not proven to be effective for control of white mould in soybeans. In fields that have a history of white mould, wider rows (at least 15"), lower plant populations, and varieties that are more tolerant should be grown.

If the crop is destined for an identity preserved market, make every effort to maintain quality. Combining should wait until soybean stems and weeds are dried down completely to avoid green staining of the seed. Harvesting of Identity Preserved (IP) beans must start later and end sooner in the day than commercial beans to prevent staining.

It is best to harvest at 14% moisture to avoid the need for drying. Harvest losses and mechanical damage may be high when soybeans are harvested below 12% moisture. Losses can be minimized if a ground speed of 4-5 km/hr is maintained. The reel speed should be adjusted to match the crop conditions.

Edible Beans

Edible bean harvest has been limited to date with the bulk of the harvest likely to happen in the next 14 days. Reported yields have ranged widely from 16 - 22 cwt/ac, depending on drainage, seasonal rainfall events, and disease. Quality has been excellent, but low seed moisture has delayed harvest in some cases. Prior to harvest, check fields for volunteer corn and weeds, such as nightshade and pokeweed, that cause severe staining of beans.

Harvest losses and mechanical damage may be high when edible beans are harvested below 14% moisture. A loss of just 5 white/black beans/ft² represents a loss of 90 kg/ha (100 lb/ac).

Combine samples of beans can be monitored for mechanical damage by using a simple seed soak test. The procedure for doing a soak test is to make a dilute solution of household bleach using one-part bleach to five-parts water. A sample of bean seed is then soaked in the solution for 5-10 minutes. Blot the seeds dry on paper towel and count the number of damaged seeds. Seeds with damaged seed coats will take up moisture quickly and will appear to either be swollen or have wrinkled seed coats.

Canola

Canola harvest is progressing rapidly with about 75% of the crop harvested. Yields have been good to exceptional, ranging from 0.8 to over 1.6 t/ac. Variations in yield are due to spring soil conditions, emergence, and seasonal rainfall. Sclerotina is evident in all fields, but lower in fields receiving fungicide treatment. High amounts of sclerotia (overwintering black bodies) can be found in canola stalks. A 3-4 year rotation between crops susceptible to sclerotinia is recommended to minimize risk of serious infection in future. Low harvest seed moisture has been a concern in some areas. Harvest is being rushed in order for wheat to be planted on timely basis.

Winter Cereals

Seeding is underway on edible bean, canola and pea fields. Plant into moisture! With dry conditions it may be necessary to plant up to 7.5 cm (3 inches) deep in order to reach moisture. This is preferable to planting shallow and hoping for rain, or leaving the seed in the bag.

With many soybean crops delayed in maturity, growers are considering seeding wheat in less conventional rotations. Wheat after oat is an excellent rotation, wheat after barley is quite acceptable, but wheat after wheat or after corn silage carries significant risks. Be sure to plant a variety with good fusarium tolerance if wheat follows corn.

Watch basis levels on different classes of wheat. Current basis bids on hard red wheat are very favourable compared to soft wheat at some elevators.

Spring Cereals

Spring cereal harvest is winding up in the last regions of the province. Barley yields have been good, oat yields have ranged from dismal to excellent dependent on rust control measures employed, and spring wheat yields range from fair to excellent. Fusarium in spring wheat was problematic again this year in many regions, but in contrast to 2008, the crop this year is often able to be upgraded with good secondary cleaning or use of a gravity table.