NORTHERN "AG" EXPOSURE

by Mark Miller
Rolette County Extension Agent

Published Turtle Mt.Star, August 4,2001

ESTIMATE CORN YIELDS IN YOUR FIELDS

With silking just finished on corn that is progressing in a timely fashion in order to mature before the average frost date, estimates of the relative grain yield can be done. First, count the number of harvestable ears per 1/1000th of an acre. With 30inch rows that is a row length of 17 feet, 5 inches and with 22inch rows count the number of ears down 23 feet, 9 inches of a row to determine the estimate. Within this ear count area, also count the number of kernel rows on the ears of every fifth plant. Also, count the number of kernels per row on these same ears.

Remember to only count kernels that are developing well (do not count kernels on the tip that are less than half the size of those midway up the ear). Average the total number of ear rows counted within the area, then separately average the total number of kernels per row within the area. If possible, move to various areas of the field and repeat the above

estimations and average your findings. Next use the following formula to determine yield:

[(average ear #) x (average row #) x (average kernel #)] / 90 = bushels per acre

Remember, this estimate of relative grain yield will be underestimated in a year with good grain fill conditions.

ESTIMATE SOYBEAN YIELDS PRIOR TO HARVEST

Soybean yields can be estimated before harvest once the full pod load is established but is more accurate closer to harvest. Yield estimates on this crop are most accurate within weeks of maturity, namely within no more than three weeks prior to harvest as pods can be dropped under stress conditions. However, check your fields todetermine how the crop is progressing from podding up through harvest.

First, find the number of feet of row needed to make 1/1000 of an acre. For 30" rows this would be 17' 5"; for 28" rows this would be 18' 8"; for 20" rows this would be 26' 2"; for 15" rows this would be 34'10"; and, for 10" rows this would be 52' 3" for the length of a single row equal to 1/1000 of an acre.

Second, find out the plant population. Count the number of plants in 10 randomly selected sample areas and average. Multiply this average by 1000.

Third, run a pod per plant count. Count the number of pods per plant on 10 randomly selected plants from each sample area and average.

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