Corn planting time is here, and have you wondered how to check the depth of your planter? Seeding depth or the variation in seeding depth can affect corn yields. Below is a great blog post from Dr. Simer Virk, UGA Precision Agriculture Specialist, on this subject.
With corn planting underway in some parts of the state, the 2023 planting season is officially here and will be in full swing over the new few weeks. That also means if you have not already, this is the perfect time to perform a thorough inspection and get that planter ready for the field. During detailed planter inspection, checking components that control seeding depth is one of the important considerations as seed depth variability during planting is one of the most common causes of delayed and uneven emergence. Seed depth variations among the planter row units are also common and can even exist on a new planter. Minimizing depth variations across the planter is important to place seeds evenly at the desired depth and maximize the potential for a timely and uniform stand establishment.
Digging seeds behind the planter is usually a common practice to check depth settings at the beginning or during planting. However, at-plant field conditions can affect the accuracy of measurement and more often it is not performed on every row unit especially on large planters. Fortunately, there is a simple and an effective way to check depth settings while preparing planter for the field. The following steps outline the process to run a block test on the planter to ensure each row unit is set to plant evenly at the target seeding depth:
1. Take two pieces of 4×4 wooden blocks approximately 16 to 20 inches long. Both blocks can be of the same length but for certain planters with other attachments too close to the gauge wheels, one of the blocks may need to be shorter than the other. Mark one side of the longer block with lines spaced ¼ to ½ inch apart (based on how precise you want to be) as shown below. You can also choose to only mark the lines for the desired seeding depths to be attained in the field such as one line at 1 inch and another at 2 inches.
2. Find a flat surface inside the shop or outside. With planter raised, set the depth setting on the row unit (to be checked) for the target seeding depth and place the blocks under that row unit so that when the planter is lowered, the gauge wheels sit on the blocks while the double-disc openers are directly in the center and not pushing against any of the blocks. Make sure the planter toolbar, parallel linkages and the row unit are parallel to the ground when the planter is down.
3. If needed, adjust the block that is not marked under the gauge wheel so that the double-disc openers can be clearly seen in front of the lines marked on the other block. Note down the reading corresponding to the lowest point of the double-disc openers on the block. This is the actual seeding depth that will be attained in the field at the current depth setting on the row unit. Compare this reading to the target seeding depth and adjust the depth setting on the row unit as needed. Repeat the steps 2 and 3 after each adjustment until the double-disc openers lines up precisely with the target seeding depth mark on the block.
4. Repeat and perform the same process (steps 2 and 3) for each row unit on the planter and record the final depth settings for each row unit that provides the target seeding depth. It is normal to have slightly different depth settings on the row units across the same planter to achieve a target seeding depth as shown below for a 4-row John Deere MaxEmerge2 planter. If the same planter will be utilized for planting more than one crop at different seeding depth, this is also a good time to check all the depth settings that the planter will be utilized for during the season. Keep a copy of these settings in the tractor cab so they can be referenced and used as needed during planting.
Using block test method is a good way to determine the proper depth settings for each target seeding depth while also ensuring seeding depth uniformity across the whole planter. In addition to using this method, when out in the field it is always a good practice to dig seeds behind each row unit to verify the actual seeding depth and make any necessary planter adjustments based on the prevalent field conditions.