Planting into crop residue and undisturbed soil requires attention to planter adjustment and maintenance. Planter maintenance is important for all farmers, particularly those in reduced and no-till systems.
A well-maintained planter gives seed its best chance, and with field operations happening in a shortened time frame this spring, planter maintenance will be as important as ever. Most of the physical responsibility for manipulating soil, placing seed and getting the seed off to a good start rests on the planter.
Longtime Iowa State University Extension ag engineer Mark Hanna, now retired, offers the following information and guidelines to help move you toward a successful planting season in 2019.
Reduced-tillage, no-till. Many producers have found through trial and error that a great deal of emphasis must be placed on the soil-engaging components of the planter since the planter replaces some tillage equipment operations used in the past. Rather than planting in a prepared seedbed, the planter can be used to create a furrow with the right depth, place the seed uniformly in the furrow, and establish adequate seed-to-soil contact.
Some first-time no-till planter operators are disappointed to see seed placement at ½- or ¾-inch depths, rather than the 1½- to 2-inch depths that they chose according to the settings on the planter. The problem is if there is not enough weight on the seed openers, or the seed openers haven’t been maintained to keep a narrow profile with sharp edges, the row unit may be “resting up” on the openers without the depth wheels touching the soil surface.
Uniform seed depth. Set your planting depth according to soil moisture conditions. Penetration of the soil by the seed openers is a particular problem in dry soil, when you may be trying to plant the seed slightly deeper. When the soil surface is dry (or when planting in soils with a coarse texture where soil moisture is limited at the soil surface), deeper planting may be required to ensure adequate moisture availability for successful germination.
Double-disc seed openers. The seed opener is responsible for opening a consistent furrow and achieving consistent seed placement. Worn beveled edges on seed opener discs tend to let soil and crop residue into the furrow, making it more difficult to insert the seed at the desired planting depth. Make sure the discs meet sufficiently at the soil entry point and have a good bevel remaining to slice through soil and crop residue.
If planting into cornstalks or heavy residue, row cleaners can be used to push residue aside ahead of the seed opener. Operate row cleaners so they move mainly residue with little soil movement, turning about three-fourths of the time rather than fully engaged into the soil.
Planter maintenance. Check the owner’s manual for your planter and talk to your equipment dealer about the best strategies for planting in no-till or heavy residue. Also, talk to experienced farmers in your area about preparing your planter for the soil type.
Be flexible and adjust planters as necessary to deal with changes in soil moisture and crop residue amounts. Also, be aware of soil moisture conditions. Watch for crop residue “hair-pinning” under the seed opener or soil sticking to the soil-engaging components of the planter.
Down pressure. Pneumatic diaphragms or down-pressure springs transfer weight from the toolbar planter frame to seed openers to penetrate the soil. Transfer just enough down pressure from the frame on parallel links to make sure depth gauge wheels are firmly resting on the soil surface. Too little pressure results in shallow seed placement, whereas too much pressure needlessly compacts soil near the seed furrow. Be especially aware of “smearing” of the seed-furrow sidewall, which indicates that the soil is too wet to plant.
Using too much down pressure or planting into wet soils will result in compacting the seedbed, making emergence and root development difficult. If using an automated downforce system, monitor your system and use just enough downforce to keep row-unit depth wheels in contact with the soil surface, but no more than is necessary.
Planter adjustments. How do you know the planter is set up correctly? In addition to monitoring seed population, check the seed furrow periodically for proper seed depth and ensure that the soil is in good contact with the seed.
Because of the importance of the seed-metering and soil-engaging components, the equipment operator should periodically check planter performance in the field. Planter monitors can let you know whether the correct number of seeds are dropping into the furrow. Get off the tractor periodically, especially as conditions change, and check seed depth, spacing, seed count and seed-to-soil contact.
For more information, see Iowa State University Extension publication PM 1492.
Follow this planter calibration checklist:
1. Seed depth. Check for appropriate seed depth and soil penetration. As soil conditions change with different locations, soil types, or the weather, it is important that operators check seed placement behind the planter for depth, spacing and seed-to-soil contact.
2. Plant population. Knowing the optimum population to plant is critical. This information will help in achieving potential yield and getting your money's worth out of any seed variety. A planter's population monitor in the cab is one way to keep track of the population that’s being planted, but you should also climb down from the cab periodically and do a little digging behind the planter. Get on the ground and do some spot checks, looking for uniform seed population and seed depth.
3. Seed opener. Inspect the seed opener and adjust as necessary. Although you may have correctly set the depth adjustment, depth wheels may not be firmly in contact with the soil surface and the planter unit may be riding up on the seed opener. Additional down pressure or weight may be necessary when planting in firm soil conditions for the seed opener to penetrate to desired planting depth.
4. Press wheels and covering discs. Look at the cover disc and the pack wheel tension. Seed-to-soil contact is usually controlled by soil coverage and compaction of press wheels and covering discs. Planters have an adjustable down pressure spring to vary the amount of surface pressure and coverage for supplying adequate soil contact. The spring pressure may need to be increased in drier surface soil conditions for adequate seed-to-soil contact and to help bring moisture up to the seed. Pressure should be decreased after surface soil moisture has been recharged by rainfall, which will avoid compacting soil around the seed.