Central Valley Bean Cooperative
Estimating Crop Yields 03/09/05 10:06:41 AM
Estimating Crop Yields
Estimating bean yields before harvest is difficult and often becomes more of an educated guess. The following method will give the producer some idea of what the crop will yield.
1) Estimated plant population
A). Based on your row width, count the number of plants in 1/1000 of an acre. Use the chart below to determine the length of row in 1/1000 of an acre.
Row width Row length in 1/1000 acre
6 inches 87.1 feet
12 inches 43.6 feet
22 inches 23.8 feet
30 inches 17.4 feet
36 inches 14.5 feet
B). The more random samples you can take from a field the greater accuracy you will have in estimating your plant population. It's recommended that fields that are 10 to 40 acres in size have a minimum of 4 counts taken. For each additional 40 acres a minimum of 1 count should be taken.
C). Count the plants in the determined length of row, average the counts and multiply your estimated plant population per acre.
2) Randomly sample 10 plants throughout the field. The best way to do this is without looking, reach down and grab a plant, then count down three plants in either direction, using the plant as a sample. This reduces the risk of selecting the larger more obvious plants.
3) Count the total number of beans ( not pods ) on these 10 plants.
4) Divide total beans ( from step three ) by 10, which gives average beans per plant.
5) Multiply plant population ( step 1 ) by average beans per plant ( step 4 )
6) Divide this number ( step 5 ) by the average number of seeds per pound for the variety being grown. This is usually 2400 for navy beans and 1200 for pinto beans. This will give you the estimated pounds per acre yield. THIS IS ONLY GUIDE TO ESTIMATING YIELD. To improve accuracy; this procedure should be repeated several times in various parts of the field. Field loss should also be deducted.