By DOUG GRAVES
Ohio Correspondent

COLUMBUS, Ohio — According to Mark Sulc, associate professor of horticulture and crop science at The Ohio State University, estimating the alfalfa neutral detergent fiber (NDF) using the PEAQ method is a five-step process:
First, simply choose a representative two-foot-square area in the field to be harvested. Second, determine the most mature stem in the sampling area using the criteria shown in the accompanying table.

Third, measure the length of the tallest stem in the two-square-foot area. The measurement should be made from the soil surface to the tip of the stem, not the highest leaf blade. The stem should be straightened for measurement. The tallest stem may not be the most mature stem.

Fourth, based on the most mature stem and length of the tallest stem, use the chart to determine estimated NDF of the standing alfalfa forage. Example: tallest stem is 28 inches, most mature stem has buds, but no open flowers; NDF = 38

Fifth, repeat steps 1-4 in four or five representative areas across the field. Take more samples for fields larger than 30 acres. Average all estimates to get a field average NDF.

According to Sulc, this procedure estimates alfalfa NDF content of the standing crop. It does not account for changes in quality due to wilting, harvesting and storage. These factors may further raise NDF content by 3-6 units, assuming good wilting and harvesting conditions.

This procedure is most accurate for good stands of pure alfalfa with healthy growth.