Wondering if you will have record high grain yields this year? Curious of that new variety you tried this year and what it will yield?
In this post, I will be explaining two different ways you will be able to estimate grain yields prior to harvest. Each of these methods will often produce an estimate that is within 20 bushels/acre of actual harvest yields.
The first method of estimating grain yield is called the 'Slide Rule' or the Corn Yield Calculator. The major advantage of this method is that it can be used as early as the milk stage of kernel development. The Slide Rule method involves kernel weight (which is figured into the equation) by using a 'fudge factor' that is based on hybrids and the environment being used today. The suggested 'fudge factor' is 80,000-85,000 kernels per 56-pound bushels. For this example we will used 85.
Step 1: Count the number of harvestable ears that is equal to 1/1000th of an acre. For 30 inch rows, it would be 17 ft. 5 in row.
Step 2: Pick every fifth ear in that row, count the number of rows on each ear and determine an average.
Step 3: Again on each of those ears, count the number of kernels per row and determine an average. (Do not count kernels on the butt and tip of the ear that are less than half the size of a normal kernel.
Step 4: The equation for yield (Bushels/acre) = (ear #) X (average row #) X (average kernel #) / 85.
Step 5: Repeat this across multiple location within the field.
Example: You have a 30-inch row field. You counted 29 ears (within the 17ft. 5 in). Counted every fifth ear with an average of 16 rows and 33 kernels. The estimated yield would be: (29 x 16 x33) / 85 = 180bu./ac
The second method of estimating grain yield is Ear weight method. This method is used when the corn has matured and is at black layer, which is around 30-35% moisture. This method uses actual ear weight and will result in a more accurate yield.
Step 1: Like in the first method, count the number of harvestable ears in a 1/1000th acre (17ft 5in).
Step 2: Weigh every fifth ear and calculate an average ear weight in pounds.
Step 3: Hand shell the same ears and determine an average moisture a hand moisture tester.
Step 4: Multiply the number of ears by the average ear weight.
Step 5: Multiple average grain moisture by 1.411 (predetermined factor)
Step 6: Add 46.3 to the result from step 5.
Step 7: Divide the results from Step 4 and Step 6.
Step 8: Multiple the result by 1,000
Example: You have a 30 inch row field. You counted 24 ears (per 17ft 5 in). Weighed every fifth ear and determined an average ear weight of 0.5 pound. The average moisture was 30%. The estimated yield would be: [(24 x 0.5) / ((1.411 x 30) + 46.2))] x 1,000 = 135 bushels/ acre.
Source: Farms.com
