ISSUE 13 August 2, 2007
It is important to swath canola at the right time in order to reduce green seed and losses from shattering. The best time to swath to optimize yield and quality is when the moisture in the seed is 30 to 35%. Seeds in the pod are completely filled and reach physiological maturity at about 40% moisture. After reaching this stage the seed loses moisture at a rate of about 1 to 3% per day. Seed color will change from green to light yellow and finally brown. The crop may be at the optimum 35% moisture stage for only a few days when weather conditions are dry. As there is usually variability in the field, like lower or higher spots, the crop may not mature evenly. Although one could swath different areas of the crop on different days this may be impractical and a decision to swath should be based on the area with the highest yield potential. Swathing should be done when 30 to 40 percent of the seeds on the main stem have turned from green to brown. Most of the seed that will have changed color will be on the bottom third of the stem.
moisture stage for swathing canola
Canola is usually ready to be cut and put in the swath 20 to 30 days after the end of flowering, which is defined as the time when only 10% of the plants still have some flowers. It is important to make the swathing decision based on actual field observations considering ridges, soil types, plant density, and other field factors.
To determine the right time to swath consider only pods on the main stem.
Avoid swathing during hot (>86 degrees F) and dry weather. Swathing during the cooler evening hours, at night, or early morning will allow the seed to dry down at a slower rate. This may lower the chance of green seed in the end product. Swathed canola is ready to harvest, under normal conditions, 5 to 14 days after cutting the crop. If there is still green seed in the pods allow a few extra days in the swath for more color change. Green seed may change color in the swath but it does not change much once the crop is combined and put into storage.
For more information about canola harvest see the extension publication A-1171 at: http://www.ag.ndsu.edu/pubs/plantsci/crops/a1171w.htm
TIPS FOR PLANTING WINTER WHEAT ON PREVENTED PLANT ACRES
For fields not planted this season due to excessive rainfall, planting winter wheat can be a viable option. The following are suggestions to help improve the likelihood of a successful winter wheat crop on prevented plant acres.
1. Consider establishing a "residue" crop. Successful winter wheat survival is largely dependant on good snow cover in the winter. During the past several years we have experienced relatively mild winters and many farmers produced good winter wheat crops on land with little or no residue. Nevertheless, having residue in the field can help catch snow and dramatically reduce the risk of winter kill. Therefore, for fields that had previously been tilled or that have little or no stubble, consider establishing a residue crop. The most effective residue crop is flax planted in early August. Flax can be established as a lightly seeded solid stand, in wide rows (i.e. 3-4 feet spacing) or as strips. Strips of flax 3 to 5 feet wide and 15 feet apart have been found to effectively trap snow while minimally depleting soil moisture. When seeding flax in strips or in wide row spacings, the drill should be set at a high seeding rate (40-60 pounds per acre) and drill spouts should be taped shut to obtain the desired spacing. Strips of flax more than 20 feet apart can be risky as they do not catch sufficient snow in most years. Flax should be seeded on or about August 1 and no later than August 15, depending on the region of the state. Establishment of flax can be difficult if moisture is limited, but in the regions of the state that have been dealing with excess moisture this year, that should not be a serious concern.
2. Break the Green Bridge - Wheat streak mosaic virus can be a very serious disease of winter wheat as there is little or no resistance in currently available winter wheat varieties. The wheat curl mite transmits this virus. This mite spreads from volunteer wheat and other grasses that are still green when winter wheat is planted. To reduce or eliminate the risk of wheat streak mosaic virus moving on to the establishing winter wheat this fall, all volunteer wheat and grassy weeds should be destroyed at least two weeks before winter wheat planting. When possible do not seed winter wheat closer than 1/8th mile to corn or fields with volunteer wheat.
3. Plant at the recommended time - In the northern half of the state the optimum period for planting winter wheat is September 1 to September 15 and for the southern half of the state September 10 to September 30. Planting prior to the recommended date unnecessarily depletes soil moisture reserves, increases risk of disease and may reduce winter survival. Later plantings generally do not develop well in the fall and can be more sensitive to winter kill, and potentially be less productive.
4. Use a winter hardy variety. This is especially true if you are not planting into residue. The varieties released by NDSU (i.e. Jerry) as well as those developed in Canada are among the most winter hardy. Data on the winter survival during 2003/2004 (the most recent season when we observed large differences in varieties to winter survival) of most of the currently grown varieties can be found at http://www.ag.ndsu.nodak.edu/aginfo/smgrains/WWsurvial.htm. Jerry, CDC Buteo and CDC Falcon are varieties for which seed is readily available in the state and that consistently have shown good winter survival. Though farmers have reported success with varieties developed for Nebraska (i.e. Wesley, Jagalene and Millennium), there is definitely more risk of winter kill when they are planted in North Dakota without residue to help catch snow.
5. Apply phosphorus at or prior to planting. About 10-15 lbs of P with the seed can improve winter hardiness. Excessive N prior to winter freeze-up, however, can reduce winter survival.
For the most recent data on winter wheat variety performance go to: http://www.ag.ndsu.edu/pubs/plantsci/smgrains/a574.pdf.
NDSU Extension Agronomist - Cereal Crops