Assessing corn and soybean stands

first_imgShare Facebook Twitter Google + LinkedIn Pinterest Early assessment of corn and soybean stands can help identify potential crop concerns early in the season. Once seedlings emerge, stand counts and visual inspection of plants can assist in identifying problems from planting, insects, and/or diseases. This is a great time to be evaluating your planter set-up to see if your winter maintenance and settings paid off. Hopefully, you checked your meters on a test stand for accuracy on singulation, performance, and inspected the working parts. Pay close attention to plant spacing within the row and make sure plants are equidistant from each other. Also, pay attention to skips and doubles, these are yield robbers.There are three common methods for taking stand counts. They are the wheel method, the 1/1000th acre method, and the hoop method. Here are some tips:• When evaluating a corn or soybean stand, only count plants that have a good chance of survival.• Keep in mind that while corn plant populations are a critical component of yield, soybean plants are better able to compensate for low plant populations and plants that are not equally spaced compared to corn plants. Wheel methodCount 150 plants and measure the distance from start to finish with a measuring wheel. Divide the number of feet traveled into the appropriate factor in the table below to determine plant population. For example, if you walked 94 feet while counting 150 plants in 30-inch rows, the population is 2,613,600 ÷ 94 = 27,804 plants per acre. You should repeat the process several times and average the results.Stand count evaluation factors formeasuring the distance when counting 150 plants. Row Width (inches)                Factor20                                            3,920,40030                                            2,613,60036                                            2,178,00038                                            2,063,350 1/1000th Acre MethodCount the number of plants in a length of row equal to 1/1000th of an acre based on row width in the table below. Multiply the number of plants by 1,000 to get plants per acre. Repeat the process in several locations in the field for an accurate estimate. Keep in mind problem spots with known issues should be evaluated separately from the rest of the field. This is my favorite method for evaluating corn plant stands. I have made a plant population rope out of 3/8-inch diameter nylon rope with a knot on each end for counting populations in 30 inch corn rows. From knot to knot it measures 17 feet 5 inches. It is easy to make several counts very quickly by counting the number of plants between the knots and multiplying by 1000. Make sure to calibrate or check the length of rope each year because the nylon rope will shrink over time. 1/1000th Acre Method. Standcount evaluation for 1/1000th acrebased on row width and number ofplants in a given row length. Row Width (inches)                Row Length 1/1000th acre (feet, inches)7.5                                                       69’ 8”15                                                        34’ 10”20                                                        26’ 2”22                                                        23’ 9”30                                                        17’ 5”36                                                        14’ 6”38                                                        13’ 9”40                                                        13’ 1” Hoop methodThis method should be used for drilled soybeans. Measure the diameter of the hoop, toss it in the field, and count the number of plants inside the hoop. Do this in at least 5 locations in the field. Multiply the average number of plants by the appropriate factor listed in the table below to determine the number of plants per acre. Notice that having a diameter of 28.25 inches allows you to simply multiply by 10,000 to obtain the number of plants per acre. This size of hoop can be made by cutting anhydrous tubing to 88.75 inches and joining it with a brass hoes barb connector to form a circle.Hoop Method. Standcount evaluation factors, byhoop diameter, for determiningsoybean plant populations. Diameter ofHoop (inches) Factor18                                24,66221                                18,11924                                13,87227                                10,96128 ¼                            10,00030                                8,87833                                7,33736                                6,165 SummaryIf a crop stand is being assessed for potential replanting, several factors should be taken into consideration, including if the field is irrigated or dryland, current plant population, plant spacing including missing plants and doubles, and the potential replanting date. There are charts available to help you determine the expected yield by knowing the re-plant date and current plant population.last_img

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