As corn planters start to roll in the fields, it is important to emphasize the importance of regular in-field checks by digging behind the planter and ensuring that the planter is set up properly for the existing field conditions and providing optimal performance. Even if growers have performed a thorough pre-season inspection on the planter, it is essential to adjust and verify the settings in the field at the beginning of the planting season. Considering the high seed costs and low commodity prices, in-field planter checks are even more critical this year to avoid any costly planter mistakes or issues that can affect crop emergence and stand establishment. While modern planting technology provides real-time feedback about planter performance in the tractor cab, it does not replace the need for manual in-field checks to assess seeding accuracy. These checks also help in the timely detection and troubleshooting of planter issues before they become significant.
A few key planting metrics should be used to evaluate the accuracy of seed metering and placement. For successful planting, the goal is to ensure that the planter is meeting the desired performance for each of these metrics. A brief description and how to assess each one of these metrics is provided below:
Applied Seeding Rate: The applied seeding rate (also called planted population) is the number of seeds per acre (or per foot length of the row) planted by the planter and is based on the target seeding rate. During in-field checks, the applied rate is computed by counting the number of seeds within a certain length of the row or seeds per foot length of the row. For optimal planter performance, the applied seeding rate should match (preferably within ±1000 seeds/ac, especially for corn and cotton) the target seeding rate.
Singulation: Singulation refers to the seed meter’s ability to precisely measure and drop one seed at a time into the seed tube. A 100% singulation means perfect seed metering with no skips or multiples and is desired. Generally, a singulation of ≥98% is deemed acceptable, especially for planting corn and cotton. When digging behind the planter, singulation can be assessed by observing the number of skips or multiples within the row.
Seed Spacing: Seed spacing indicates the distance between two adjacent seeds within a row and is based on the target seeding rate and row spacing. The best method to evaluate seed spacing is to use a tape measure and measure the seed-to-seed spacing for a certain length of the row. It is important to have this number as close as possible to the target seed spacing, as it also affects the applied seeding rate.
Seed Depth: Seed depth refers to the distance between the soil surface and the seed in the furrow. This is a critical measurement as modern planting technology does not provide any feedback regarding the seed depth, so performing an in-field check by digging behind the planter is the only (and best) way to evaluate seed depth accuracy. Using a tape measure or seed depth tool is recommended to measure seed depth. It should be measured for multiple seeds within a row and compared with the target seed depth. A good rule of thumb is to attain the actual seed depth within ±1/10 in. of the target seeding depth (inches).
Seed-to-Soil Contact: Adequate and uniform seed-to-soil contact is crucial for successful germination and plant emergence. Planting conditions and planter settings directly impact seed-to-soil contact and seeds’ access to adequate moisture and temperature. When checking seed-to-soil contact, check for any residue touching the seed or air pockets around the seed in the furrow. The soil around the seed should be firm (not too loose or compacted) and moist to promote uniform germination and strong root development.
Remember, performance can vary from one row unit to another, so it is essential to dig behind each of them to check the above-listed planting metrics. Similarly, the applied rate, singulation, and seed spacing (generally displayed as seed spacing quality) should also be monitored for each row unit on the in-cab display/seed monitor during planting. Also, an important point to remember when troubleshooting planter issues is to adjust only one setting at a time and check its effect on planter performance.