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Fall alfalfa stand assessment

Paul H. Craig Published on 19 October 2010

Fall is a good time to consider evaluating existing alfalfa stands to estimate what stand conditions might be present next spring. Assessing stands in the fall helps to identify potentially weakened stands that will become more prone to winter injury.

A fall assessment can also result in determining that the stand is no longer dense enough for high yields and needs to be treated with an herbicide this fall and rotated to corn in 2011.

Stand density affects yield and quality of all forages but the final decision on rotation is based on individual farm goals and economics. However, eventually a rotation decision must be made.

Fall alfalfa stand assessment is an easy task to accomplish. Simply make a 1 foot square frame of wire. Take this frame and as you walk across your alfalfa stands toss it on the ground and count the number of alfalfa stems within the frame.

Take and record multiple counts across your stands. Stands with 55 stems per square foot or more are fine. Stands with less than 39 stems per square foot are definitely candidates for rotation. However, when counts are between 40 and 54 stems per square foot, closer evaluation next spring will be needed.

Winter injury of alfalfa is affected by many factors. Older stands, varieties with lower winter hardiness ratings and disease ratings, stands grown on soils with low potassium levels and low pH (less than 6.6) and stands with intensive cutting management are more prone to winter injury. How are your stands this fall? Take the time now to take an evaluation of your existing stands and plan accordingly.  FG

Penn State Field Crop News, Vol. 10, No. 30