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Oklahoma State University Stillwater, OK |
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Oklahoma Alfalfa |
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Oklahoma State University Stillwater, OK |
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Oklahoma Alfalfa |
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Weed-it Tips Producers' Question: What can be done to thicken up erratic alfalfa stands planted this fall? Conditions for getting good stands of alfalfa are seldom ideal, so many stands are going to need a lot of attention. Some areas did not receive enough rainfall to get good emergence of alfalfa while others got too much, and this resulted in washed out plants. First thing to do is to scout your fall planted stands now to determine the current status. Some suggested actions are as follows: 1) If standing water killed alfalfa in low areas, then you need to drain these wet areas before planting back to alfalfa. 2) If more than 20-30% of field is washed and has a lot of areas where there are no plants within one square foot area, then you need to consider saving only a part of the field, if possible, and drilling wheat into the remainder of the area after leveling. It is too late to plant alfalfa this fall. Spring planting of alfalfa would be another option, but spring planting is more risky than fall plantings, and stands often are not as uniform. 3) If less than 20% of field is washed and/or there are some thin areas, then consider leveling these areas and replanting these areas next March. We do not usually recommend thickening stands, but when areas are newly established area, then some success is possible. 4) If alfalfa stand is not a full stand (10 seedling plants /sq. ft.) but fairly uniform over the entire area, then it can still be productive with as few as 5 plants/sq. ft. However, it is critical that alfalfa is protected from insects and weeds are controlled. It is important to not lose any more alfalfa plants. Since these thin stands do not occupy all of the area, first year's production will be reduced by about 20%. However, alfalfa production after the first year is normally comparable to that of full stands. Weed control is more important in these thin stands than in a full stand because weeds will come into the areas not occupied by alfalfa. These weeds compete with small seedling alfalfa for nutrients, water, and light, resulting in reduced growth of alfalfa, and likely some loss of alfalfa plants. Since seedling alfalfa is not highly competitive, any aggressive weeds will result in reduction of alfalfa growth and possible stand loss. It is critical that fall planted alfalfa fields are scouted and weeds controlled as soon as possible (this fall). There are usually good spray days in October and November when weeds are actively growing and fields can be sprayed. A good spray day is a "shirtsleeve day" when air temperature is warm and soil moisture is adequate for active weed growth so herbicides are taken in and weeds controlled. Spring spraying to control weeds in fall planted alfalfa is not a viable option for most situations. |
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| Jim Stritzke Former Alfalfa Weed Control Specialist Department of Plant and Soil Sciences Oklahoma State University |
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