ISSUE 13 August 7, 2008
Canola fields may have some weeds or later maturing canola plants and a decision needs to be made about swathing the crop prior to harvest. To determine when the field is ready for swathing examine plants in different parts of the field. The crop is considered ripe and ready to swath when 30 percent to 40 percent of the seeds on the main stem have turned color. After swathing the canola seed should be allowed to ripen in the swath from 10 to 14 days before combining. The seed moisture and green seed count need to be checked before combining. The moisture content of the canola seed should be around 10 percent and the green seed count should be below 2 percent. Check combines, trucks and bins for areas that may leak seed during harvest and transportation. Gaps and holes should be repaired. The travel speed of the combine should be similar to the speed of the pickup so the swath will be lifted gently. The cylinder speed best used is half to two-thirds of the cylinder speed used for small grain harvest. The speed should be just fast enough to break open the seed pods. Make sure no over-threshing of the pods and stems and overloading of the sieves takes place. Fan speed should be low to avoid blowing canola seed out of the combine with the chaff. For more information on swathing and harvesting canola see http://www.ag.ndsu.edu/pubs/plantsci/crops/a1171w.htm.
SEEDING GREEN MANURE OR FORAGES INTO WHEAT STUBBLE
Wheat stubble can be an excellent seedbed for no-till planting green manure legumes, alfalfa, or grasses. With no-till, soil moisture is conserved, erosion is reduced, weed seeds remain buried and tillage expenses are eliminated. One of the bigger challenges is heavy residue that might interfere with proper drill operation and seed placement, seed contact with the soil or partly smother new seedlings. Residue can be especially troublesome right behind the combine even when using a good straw chopper and spreader. When planting legumes the best way to minimize this is to bale the straw and be sure to have a well-functioning drill. Of course there is a need for some soil moisture for the seed to germinate. In some areas in western North Dakota there may not be enough moisture to seed a crop into the wheat stubble. Late summer weeds, such as annual weeds that develop after harvest or volunteer wheat that sprouts later in the summer, provide another challenge. Control weeds that exist prior to planting with herbicides like glyphosate and be ready with post-emerge herbicides for weeds or volunteer wheat that emerge later. To ensure a good stand consider cross-drilling or double-drilling. This means planting one-half of the seed while driving in one direction and the other half while driving (in the same field) at an angle to the first direction. This helps fill in any gaps and plants will develop a closed canopy quicker, which leads to improved weed control earlier in the season.
Extension Agronomist - Broadleaf Crops
BUGGY WHIP CORN
With the recent moderate weather, we have not been able to catch-up on the heat units needed for corn and in some cases we are now falling further behind the long-term average. Maturity issues aside, the corn crop looks respectable in regions of the state where drought has not been problematic. In the last couple of weeks, I have visited a number of fields where the upper-most leaf of the corn plants was curled so tightly that it looked like a buggy whip. Buggy whip corn is, in fact, a frequently used name to describe this phenomenon. Twisted whorls or buggy whipping is most commonly a problem of young corn plants (five to six leaf stage) and occasionally can be traced to a misapplied herbicide or a severe stress. This year, however, the twisted whorls are occurring much later in the development of the plant. In some plants these leaves are restricting the emergence of the tassel (see accompanying photographs). Given the fact that these plants are observed in fields with differing herbicide applications and with different hybrids, buggy whipped corn this year is most probably an environmentally induced plant response. Buggy whipping in corn that cannot be traced to an abiotic stress or to herbicide injury most commonly occurs when conditions favor rapid growth after a period of slow growth. The cool weather that persisted later into the season than normal most likely has predisposed plants to mid-season buggy whipping this year. These tightly curled leaves will generally unfurl with little impact on subsequent development and yield. In some fields this year, however, the whorls were so tightly wrapped that the tassels emerged through the side of the whorl. In some cases, the tassels emerged after pollen had been shed. Given that corn produces an abundance of pollen, buggy whipping that causes the loss of a few tassels will probably not impact yield. Buggy whip corn was not just a problem in North Dakota this year, as it was also reported to be common in Iowa (see http://www.extension.iastate.edu/CropNews/2008/0711elmorerobertson.htm).
Examples of the tops of buggy whipped corn plants.
Tasseling delayed by tightly curled leaves.
Extension Agronomist – Cereal Crops