Ontario Field Crop Report
May 2, 2007
by OMAFRA Field Crop Specialists
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.omafra.gov.on.ca/english/crops/index.html. Referenced OMAFRA Publications include Publication 811 Agronomy Guide for Field Crops ($20), 812 Field Crop Protection Guide ($15), 75 Guide to Weed Control ($15), and 505 Ontario Weeds ($15). These can be obtained from your OMAFRA Resource Centre, or by calling 1-888-466-2372.
Corn
Corn acreage in Ontario is expected to increase significantly this year. Most of the increase in corn acres will come at the expense of wheat acreage. The wet fall reduced the amount of winter wheat planted. Late planting dates, wet fall conditions, and the challenging winter weather resulted in poor winter wheat survival in many areas. Statistics Canada reports that the March planting intentions for corn in Ontario are up 32% to 2.2 million acres. Canadian corn use for ethanol production is expected to increase by 24%.
Less than 10% of the Ontario corn crop is in the ground as of May 2nd. Although the ideal planting dates are in the first half of May, it is important to plant when the soil is fit, rather than by the calendar date. Field operations when the soil is wet will lead to soil compaction, that can decrease yield much more than planting a few days after the ideal corn planting date.
Soil temperatures are generally at or above the 10oC (50oF) required for corn germination. Keep an eye on the weather forecast. If cold temperatures are forecast, it may be advisable to delay planting. Corn seed that takes in cold water can suffer from “imbibitional chilling injury”. Cool wet conditions following planting can make the seed more susceptible to seedling blight diseases. Cold temperature injury can make the roots more prone to infection and blight. Seed treatment fungicides are generally effective for 10 to 14 days, but that can be shortened under saturated conditions.
Winter Cereals:
Warm temperatures have boosted the wheat crop. Tremendous variability in stands exists, mainly due to drainage and the excess moisture received last October. Winter survival is some of the poorest in years, with up to 50% failure in heavy clay soils, and still a few killed out areas in the best drained soils. While final acreage reports are not yet tabulated, it appears that 15 to 20% of the wheat crop may be replanted to another crop. Any growers still trying to assess winter wheat survival can utilize the document “Assessing Winter Wheat Stands” available at http://www.ontariowheatboard.com/Assessing_Winter_Wheat_Stands.pdf .
Early planted advanced crops in Essex County are 20 cm tall and at growth stage 31 (first node). The growing point has moved above ground in these fields. Later fields to the north are just beginning to tiller, or growth stage 21. Nitrogen applications were made in a timely fashion and are essentially complete across the province.
Weed control timing is now! Winter annuals are bolting, and early annuals have emerged. Scout your fields! With the holes and gaps in most winter wheat fields this year, weed control will be essential in almost all fields. After wheat reaches growth stage 31, increased damage occurs from wheel traffic, and herbicide tolerance of the crop begins to decline. To avoid herbicide injury, night time temperature the day before, the day of, and the day after application should be above 2°C for bromoxynil/MCPA and Refine Extra and above 5°C for Estaprop.
Disease levels in the crop remain extremely low, far below thresholds for control at this point. Research at the University of Guelph by Mike Cowbrough OMAFRA field crop weed management specialist, indicates a slight increase in potential crop injury from herbicide/fungicide tank mixes, but no negative impact on efficacy or yield from these tank mixes.
Spring Cereals:
Planting is nearing completion, with 85% of the crop in the ground. Frost seeded cereals have emerged with excellent stands, and are now at the three leaf stage. If planting is delayed beyond May 10th, consider changing crops. Yields decline by 1.5 bu/ac/day after May10th. If spring cereals are required for the straw, shift to 6 row barley varieties. Six row barley varieties tolerate heat stress and late planting better than other cereal types.
Forage
Forage crop development has been delayed by cool conditions through much of April. Grasses have generally been growing more vigorously than alfalfa, but the legumes are poised to grow quickly with some warmer weather.
Winter survival of alfalfa has been good to excellent in most areas, including eastern Ontario. The exception has been on some poorly drained fields. Damage has ranged from low areas that drowned out from frequent saturation last fall, to fields with extensive heaving. Heaving is worst in areas that did not receive complete snow cover, where the wet soils froze and pushed the alfalfa crowns out of the soil.
Nitrogen can dramatically increase the yield of grass stands. Good grass stands with less than one-third legume, can benefit from 50 to 100 lbs/acre of nitrogen. Optimum rates depend on the cost of nitrogen, anticipated value of the hay, thickness of stand, moisture conditions, and whether it is pasture or hay. The first application of nitrogen for hay should have been made as early as possible in the spring at green-up. Additional applications can be made after each harvest or grazing rotation.
Pasture
Turning livestock out too early, before there is adequate growth, will stress the pasture and result in a reduced total carrying capacity over the season. Early turnout may require supplemental feeding of hay on a sacrifice pasture. Waiting too long can cause problems trying to keep up to the rapid spring growth phase. Excess spring flush pasture that cannot be grazed should be harvested as hay or haylage.
In a continuous grazing system, pastures should be 10 to 15 cm (4 - 6 inches) before turnout, depending on grass species and stocking rate. In a rotational grazing system, livestock can begin grazing earlier, at 8 to 10 cm (3 - 4 inches) but should be moved through the first rotation very quickly in order to keep up with the rapid spring growth. The most efficient forage height for a cow to graze is from 10 to 25 cm (4 - 10 inches) and 8 to 15 cm (3 - 6 inches) for sheep and horses.
Changing from a continuous grazing system to rotational grazing by subdividing fields and moving livestock, can double the forage production and reduce the amount of hay required during a dry summer slump. The more paddocks in a rotational system, the better the results. Forage rest (regrowth) periods should be about 30 days between rotations, depending on growing conditions. Ideally, daily moves to a fresh pasture with a 30 paddock system will optimize forage growth and livestock production. A 6-7 paddock system with moves every 4-5 days will provide the 30 day rest period and works well. Even a less intensive 4 paddock, 10 days grazing, 30 day rest system can increase production over continuous grazing.
Soybeans
Take the time to calibrate your drill. Soybean seed varies considerably in size between varieties and years. Seeding rate is less critical in soybeans than corn, but it is still important. Too high a seeding rate adds unnecessary seed costs and may increase lodging and white mould. The recommended seeding rate in 7.5 and 15 inch rows is 200,000 seeds/ac with either conventional or no-till drills. The recommendation for seeding with a planter in 15 inch rows is between 150,000- 200,000 seeds/ac. In heavy clay soils, early planting, or in tougher conditions, increase seeding rate by 5 – 10%. If planting under less than ideal conditions, consider using a soybean fungicide seed treatment. Ontario research has shown that using a fungicide seed treatment under conditions favorable for disease development can result in a plant stand increase of between 5 and 20%, which can make the difference between an acceptable stand and a replant decision.
A uniform seeding depth is important. Due to the high water requirement for germination, plant 1 cm (½ inch) into moisture, but not deeper than 5 cm (2 inches) at this time of year. A good rule of thumb is to aim for a seeding depth of about 3 cm (1.5 inches). Precise seeding depth may be difficult to achieve with some seed drills, especially in reduced or no-till fields. Adequate down pressure, ballast and the use of a coulter cart can help achieve proper seeding depth. It’s important to have good seed-to-soil contact and a closed seed slot.
Spring Canola
About 60% of intended spring canola acreage has been planted. Be sure to calibrate the seed drill. Target seeding rates need to account for large differences in seed size between varieties. Based on a 75% final plant stand, the target seeding rate is 0.3 lbs/ac more than the stated seed size given in grams per 1000 seeds. For example, the seeding rate for a variety with a seed size of 4.5 gm/1000 seeds should be 4.8 lbs/ac. Aim for quick, even emergence by ensuring good seed-to-soil contact and controlling planting depth. Packing before planting firms the seedbed, and helps control seeding depth.
Flea beetles are now emerging from over-wintering sites. High populations have been reported in New Liskeard. Flea beetles have been a problem the past couple of years. At temperatures of 15 – 20ºC, flea beetles become much more active, taking flight in search of food. Populations can explode under warm, calm, sunny weather. Seed treatments provide 2 to 4 weeks of control under light to moderate flea beetle pressure. Canola stands should be monitored for 3-4 weeks following emergence. For information on scouting and control, refer to OMAFRA Publication 811, Agronomy Guide and Publication 812, Field Crop Protection Guide.
Winter Canola
The majority of winter canola survived the winter with adequate plant stands. Canola fields in southern growing areas are making excellent progress and starting to bolt. Scout immediately for volunteer cereals. The tolerance for cereal grain in canola is very low. Optimum control is achieved when cereals are in the 2-leaf to early tillering stage of growth.