August 2021 URL: Estimating Corn serial Yield prior to Harvest R.L. (Bob) Nielsen Agronomy Dept., Univ. West Lafayette, IN 47907-2054 email address: rnielsen in ~ Twitter:

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Largest ear that corn in Nebraska, ca. 1908. Courtesy of the Nebr. Historical Society.

ancy colored yield maps are fine for verifying grain yields at the finish of the harvest season, however bragging civil liberties for the highest corn returns are developed earlier 보다 that down at the key Street Cafe, ~ above the corner of 5th and Earl. Part patrons of the cafe start "eyeballing" their yields as shortly as their plants reach "roasting ear" stage. Several of the males there are pretty good (or simply plain lucky) at estimating yields before harvest, if the approximates by others space not also close to gift within the proverbial ballpark. Interestingly, castle all usage the very same procedure described as the Yield ingredient Method.

Yield component Method

Other pre-harvest productivity prediction methods exist (Lauer, 2002; Lee & Herbek, 2005; Thomison, 2015), however the Yield component Method is more than likely the most popular because it have the right to be used well front of harvest; as beforehand as the so-called "roasting ear" or milk (R3) stage of kernel development. Under “normal” conditions, the kernel milk phase occurs about 18 come 22 job after pollination is complete (Nielsen, 2019). Approximates made earlier in the kernel development duration risk gift overly hopeful if subsequent major stresses reason unforeseen kernel abortion (Nielsen, 2018).

The productivity Component method was originally defined by the university of Illinois many years back and is based on the premise the one deserve to estimate grain productivity from estimates of the yield components that constitute grain yield. This yield components include number of ears every acre, variety of kernel rows per ear, number of kernels every row, and weight every kernel. The an initial three yield components (ear number, kernel rows, kernels/row) are easily measured in the field.

Final load per kernel obviously can not be measured until the grain is mature (kernel black layer) and, technically, at a grain moisture of 15% due to the fact that that is the typical moisture value supplied to determine a 56-lb sector bushel. Consequently, an average value because that kernel weight is offered as a proverbial "fudge factor" in the productivity estimation equation. As first described many years ago, the equation originally used a "fudge factor" the 90, which stood for 90,000 kernels per 56-lb bushel (15% serial moisture). In terms of how kernel weight is usually measured in research, this would be equal to around 282 grams per 1000 kernels (15% grain moisture).

recognize that actual kernel numbers per 56-lb bushel are influenced by both cultivation conditions and also hybrid genetics. Kernel load from year come year for the very same hybrid can easily vary by 20,000 kernels per bushel or more simply as result of variability in growing problems during the grain filling period. Consequently, the number of kernels per bushel have the right to vary significantly amongst years or fields within years. Typical kernel load in several of our current trials has actually ranged indigenous 67,000 come 94,000 kernels every 56-lb bushel, v an typical of about 76,000 every 56-lb bushel.

Crop uniformity also influences the accuracy of any yield estimate technique. The less uniform the field, the greater the number of samples that should be taken to estimate yield because that the field. There is a fine line between fairly sampling disparate areas of the field and sampling randomly in ~ a field so as no to unfairly predisposition the yield estimates up or down.

At every estimation site, measure up off a length of a single row equal to 1/1000th acre. For 30-inch (2.5 feet) rows, this equates to 17.4 linear feet. TIP: For various other row spacings, divide 43,560 through the heat spacing (in feet) and then divide that result by 1000 (e.g., <43,560 ÷ 2.5> ÷ 1000 = 17.4 ft). Count and record the number of ears top top the plants in the 1/1000th acre of row that friend deem to it is in harvestable. TIP: execute not count dropped ear or those ~ above severely lodged plants unless you space confident that the combine header will have the ability to retrieve them. for every fifth ear in the sample row, record the number of complete kernel rows per ear and also average variety of kernels per row. Climate multiply each ear"s heat number by its variety of kernels per row to calculation the total number of kernels because that each ear. TIPS: do not sample nubbins or obviously odd ears, unless they fairly represent the sample area. If heat number changes from target to reminder (e.g., pinched ears because of stress), estimate an mean row number for the ear. Don"t count the extreme butt or pointer kernels, but rather begin and also end whereby you perceive there are complete "rings" of kernels roughly the cob. Carry out not counting aborted kernels. If kernel numbers every row space uneven among the rows of an ear, estimate an average value for kernel number per row. calculate the average number of kernels per ear by summing the worths for all the sampled ears and dividing through the number of ears. EXAMPLE: For five sample ears v 480, 500, 450, 600, and also 525 kernels every ear, the average variety of kernels per ear would equal: (480 + 500 + 450 + 600 + 525) divided by 5 = 511 calculation the yield because that each website by multiply the ear number (Step 2) by the average number of kernels per ear (Step 4) and then splitting that result by a kernel weight "fudge factor". Unless your seed firm can carry out some insight into kernel weight values for their hybrids, I indicate simply performing different calculations utilizing kernel load "fudge factor" values equal come 65, 75, and also 85. This selection of values probably represents that most frequently experienced in the main Corn Belt. If grain filling conditions have been an especially stressful, then take into consideration using greater kernel weight "fudge factor" values between about 90 and 100. Example: Let"s to speak you counted 30 harvestable ear at the very first thousandth-acre sampling site. Let"s additionally assume the the average number of kernels per ear, based upon sampling every 5th ear in the sampling row, to be 511. Utilizing "fudge factor" worths of 65, 75, and also 85; the estimated selection in productivity for the sampled site would (30 x 511) divided by 65 = 236, or divided by 75 = 204, or separated by 85 = 180 bushels every acre. Repeat the procedure throughout field as countless times together you deem representative.

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Tally and average the results separately for each "fudge factor" supplied for the calculations.

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