Frost Protection for Crops
A number of years ago, Dr. Steven E. Lindow who is a pathologist at the University of California, discovered that frost damage to crops is done by the formation of ice crystals around the bacteria called pseudomonas syringae. It forms on the leaf surface of every crop. The moisture in a plant leaf will form an ice crystal around this bacteria which, in turn, punctures the cell wall of the leaf and the rest of the plant tissue.
If this bacteria is killed by the application of copper, the formation for the nuclei of ice crystals will need to be formed on other bacteria which will reduce the temperature at which these ice crystals are formed. By controlled the above bacteria by the use of copper, the temperatures that are needed to cause ice crystals can be reduced by 4°F. This technology has been known for a number of years.
Stoller suggests that 1.0 liter per acre of MP Copper can effectively control this bacteria that is preferred by the nuclei of ice crystals on crops that are subject to frost damage.
When applying this technology, there are several questions that are asked, which may be of interest to growers who use this technique for frost protection.
1. Does the copper which is applied for frost protection now, benefit next year's crop in any way?
The answer is Yes. When the residue of the plants is decomposed in the soil, the copper is released for next year's crops and following crops. If the residue is burned, the copper is released immediately for next year's crop use.
2. If 1.0 liter per acre of MP Copper will provide 4°F protection, will a heavier rate provide more degrees of protection?
The answer to this question is No. If 1.0 liter of copper will control the growth of the above bacteria, a larger amount of copper is not needed.
3. Does the protection by the use of copper on frost damage vary with the maturity of the crop or any other condition?
The answer to this question is Yes. Copper will only control the bacteria for approximately 7-10 days. The effect of copper will then be reduced and the bacterial will once again colonize the leaf surface of the crops.
4. What happens if applied now and frost doesn't happen for beyond 10 days?
As mentioned above, the effects of the copper will wear off. The preferable application time is anywhere from one day to ten days before the crop frost occurs.
5. Is there a possibility that the application of copper will result in accelerated maturity of the crop or leaf damage to the crop?
There is a possibility that the copper will cause leaf foliage spotting and burn. If the grain crop is less than 30% moisture, any stress that copper applies to the plant will tend to accelerate maturity and tend to accelerate the dry down of grain. Realizing that the addition of MP Copper to any application may cause tissue burning, the grower should be aware of this before the application is made. At this late stage of growth, all of the sugars that are necessary for grain fill have already moved out of the leaf. Any sugars that are left which could cause additional grain sizing, will be located in the stalk or stem of the plant.
Stoller Enterprises, Inc. is now conducting research on other methods for controlling frost damage. At this time, our research indicates that frost damage can be avoided by the increased amounts of abscisic acid that are formed in the plants. It is the abscisic acid which causes plant maturity. Copper will, in fact, increase abscisic acid in plants. There may be another method to do so, however, which will reduce the frost avoidance temperature greater than 4°F. It is possible to find a method to reduce frost which will be effective over a longer period of time than the present period of 10 days.
Hudye Soil Services has secured a limited supply of Copper for frost-protection trial purposes and is available on a first-come, first-serve basis. Contact Hudye Soil Services at (306) 594-2330 to secure your supply.
Printer Friendly Version
