Coming out of a wet fall, winter wheat conditions are variable across the province. Bare spots from standing water and poor drainage have been reported in some areas, especially on heavy clay soils. In many cases it may be too early to decide on whether to keep a “spotty” field. Higher wheat prices are driving growers to keep what they would have likely ripped up in previous years.
Before making any big decisions for your wheat, it is a good idea to do a stand assessment (Table 1). Fields should be walked after a week or two of warm weather and growth has resumed. Prioritize areas that were planted shallow, had frost heave problems, were planted with a variety that has poor winter hardiness, were planted late or had ponding and ice throughout the winter. Conduct several stand counts and plant health assessments throughout the entire field to get a broader perspective. Try not to focus only on the bad spots!
Table 1. Stand assessment and yield potential in winter wheat.
|Number of Plants||Number of Plants||% Yield Potential||Planting Date||Planting Date|
|Per metre of row||Per foot of row||Yield t/ha|
|Oct 5||Oct 15|
223 plants/m (7 plants/ft) of row, healthy and evenly distributed plants.
If you have bare areas, your options are limited but can include seeding in spring wheat, a cover crop (e.g., clover) or spraying the area one or more times to prevent weed growth and seed set. Spring wheat areas will need to be harvested separately or the crop will not be suitable for milling. After a cold event, fields should be assessed after a few days of warm temperatures. At that point, any injury will become evident. Fields that are most advanced should be checked first as they are most at risk. Assess low lying areas, especially if the nights were calm with little to no wind.
Early assessments of overwintered alfalfa are important for deciding whether a stand is productive enough to keep. Since harvest costs per acre do not significantly change with yield, maintaining high-yielding stands keeps the cost per tonne of forage low. Plant counts are the “early warning system” that indicate whether a stand should be terminated (Table 2). These can be done shortly after alfalfa breaks dormancy. To accurately assess alfalfa stands you must inspect the field in several locations. This involves digging up plants and looking for leaf and bud vigour, resistance to root bark peeling and a good internal root colour (white to cream colour). Only count plants that are alive and healthy. Dead plants, or those with discoloured, ropey, or rotting roots should not be included in the plant count.
Table 2. Assessing alfalfa stands using the plant count method.
|Age of Alfalfa Stand||Desired plant count per square foot|
If the plant count falls below the target, the stand should be considered for termination. Alfalfa is autotoxic, which means that mature plants produce chemicals that prevent young alfalfa plants from germinating and/or developing healthy roots. Alfalfa cannot be overseeded into alfalfa to thicken up the stand. Rotating to a grass crop, such as corn, cereals, or sorghum-sudangrass, will allow the next crop to take advantage of the nitrogen credit from alfalfa and provide time for the autotoxicity to disappear. In general, a year out of alfalfa is recommended before re-establishing alfalfa in the same field.
Winter survival and plant populations are being assessed in winter canola. Fall armyworm caused significant damage in a few specific fields last fall. Slug damage was also significant in no-till fields. There are reports of poor winter survival in fields that received frequent rains after seeding. In some of these excessively wet fields the crop did not grow in the fall, and in others the moisture resulted in shallow root systems where plants were not well anchored and are now heaved out of the soil. Healthy plants should be well anchored without exposed roots. Cut some plants off at the soil surface to ensure the stems and crowns are not hollow or necrotic. While leaf tissue may be purple, brown, or rotted off, plants should have bright green tissue at the growing point. An ideal stand has 50 plants/m2 (5 plants/ft2) but if plants are healthy and evenly distributed stands of 20 to 30 plants/m2 can be adequate. Nitrogen and sulphur should be applied when the soil is fit for travelling on the field, after the crop is confirmed to be healthy and prior to stem elongation.