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AgAlerts 2006 From Griggs County
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Issue # 1m April 26, 2006
The 2006 planting season is just underway and with every spring there is a threat of frost injury. The degree of frost injury will depend on the temperature, time of duration, plant stage and location. The following is a summary of frost tolerance for most ND field crops.
Small Grains: Due to the position of the growing point under the soil surface, small grains are very tolerant to temperatures as low as 20 degrees F. The growing point will be below the soil surface until the 5 1/2 leaf stage to jointing. Frost symptoms that usually occur is the above ground leaves wilt, become discolored or dark green in appearance. Depending on environmental conditions, recovery is quick with new leaves emerging from the stem with in 2 to 3 days. Under extreme temperatures, the stem may wilt and possibly die. Winter wheat can have different problems. Since spike development begins around the 5 1/2 leaf stage, frost at this time could cause damage to the developing spikelets which may result in loss of kernels. Damage will be noticed upon head emergence. The head and awns on the top of the plant may appear white.
Corn: The growing point is protected under the soil until the plant reaches the V5 growth stage (five true leaves). Leaf loss above the growing point will have a small effect on corn growth and yield when injured in the early growth stages. If injury is suspected, pull the entire plant, cut the stem length-wise and examine the growing point. A healthy growing point will appear white to light yellow in color. The length of recovery will depend on the extent of injury to the growing point. Uninjured growing points recover in 2-3 days.
Field Peas: Even though field peas are a legume, the type of emergence differs from another legume grown in ND, soybean. Field peas have an "active epicotyl" type of emergence. This type of emergence will have a terminal bud that will emerge above the soil. There will also be two axillary buds located on the two nodes beneath the soil surface. If the above ground tissue is damaged, growth will occur from the axillary buds. Recovery usually occurs within 3 days after damage. If no new growth has occurred by this time, dig up the plant and look for new growth. If no new growth is found, the plant is most likely dead.
Soybeans: Have an "active hypocotyl" type of emergence. This type of emergence the hypocotly begins to elongate by cell division and cell enlargement. The hypocotyl will form a hypocotyl arch which will serve as the soil penetrating structure. Once it reaches the soil surface, sunlight will cause the arch to straigthen out and begin upright growth. The growing point is above ground once the cotyledons emerge. Soybeans are easily damaged by frosts in the 28 to 32 degree range. Temperatures of 28 degrees for any extended period of time can severely damage or kill soybean seedlings. Recovery will depend on the amount of damage to the growing point, cotyledons and stems. Warm sunny temperatures will help with recovery.
Sunflowers: Has the same emergence as soybean but can withstand lower temperatures. Sunflower can withstand temperatures in the 25-26 degree range for short periods of time at the seedling stage. As the plant grows, the later leaf stages (V2 - V6) the plant becomes more sensitive to frost. The V2 stage limit is 26-27 degree range while the V4-V6 stage limit is 28-29 degree range.
Canola & Flax: These are the most tolerant crops with an "active hypocotyl" type of emergence. These crops can withstand short term temperatures down to 24 degrees. Injured plants usually recover within 2-3 days. After 3 days and the stand is not recovering, replanting should be considered depending the remaining plant population.
Summary: Frost injury will cause plant tissue to become water soaked and dark green in appearance along with wilting of stems. Do not try to assess damage too soon for crops that have below the soil growing points. Plants with growing points above ground can be assessed earlier and replanting decisions can be made. The amount of stand reduction will also be a major factor in whether replanting is necessary. In conclusion, look at the symptoms and stand population or have a crop scout help in determining your options.
Each year I start out AgAlerts with this remedy. Up until last spring, I never had to use it. My dog was out for a little stroll across the road from the house checking out a slough. That is when she ran into her first close encounter with a skunk. She came running home and my wife was nice enough to let her into the house without knowing what she encountered. Her trail was easily followed throughout the house. I finally got her outside and into the kennel. I got a hold of the necessary products and mixed up the potion. Getting a sponge plastic gloves and put a pair of handy-andy gloves on over the plastic gloves, I proceeded to wash the dog down. It is very important to keep the mixture out of eyes and nose. I was truly amazed how fast the foul smell was gone. She only had some scent around her eyes and nose but on the rest of her the skunk smell was not very noticeable. The only problem is that Greta is a black lab and the peroxide helped turn her into a chocolate lab. Needless to say, I was impressed with the results.
Here's the potion:
1 quart of 3% hydrogen peroxide
(from a Pharmacy)
1/4 cup baking soda
1 teaspoon liquid soap
Mix together and wash, keeping the mixture out of the animal's eyes, nose and
mouth. Follow with a thorough tap water rinse. Repeat if necessary.
Source: Countryside & Small Stock Journal (Farm Show,
Vol. 19 #4, 1995)
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E-mail: john.swenson@ndsu.edu
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