THE FUNDAMENTALS OF SEED PLACEMENT

:: Rethinking No-Till Seeding

This photo shows perfect seed placement in a no-till seedbed. Loose material over the seed is easily brushed away to reveal the seed ‘locked into’ the bottom of the ‘v’—it is tucked in tightly & would need to be pried loose (and you might have trouble finding it!). The upper portion of the sidewalls created by the opener blades has been completely broken up by the closing system, but the very bottom of the ‘v’ is undisturbed. If you excavate several rows and find that all the seeds are being placed like this, you can be assured that you are doing a good job (although it would be wise to periodically check at various locations)—if not all the seeds are being placed properly, it is time to do trouble-shooting. (Note that in very wet high-clay soils, the sidewall will not crumble this completely, but will still be disrupted.)

The germinating seed and seedling first encounters an environment created by your seeding equipment. In addition to controlling depth and spacing, your seeding equipment and attachments affect the uniformity of seed-to-soil contact and the amount and condition of the soil placed over the seed. This environment determines the rate of air and water exchange during germination and early growth, as well as the resistance the seedling encounters during emergence and root system development.

Proper agronomic placement of all the seeds is extremely important for optimum emergence, early growth, and eventual yield. The following characteristics are desired for every seed planted: (1) the seed is embedded into the moist furrow bottom at a consistent depth; (2) the furrow sidewall is shattered to cover the seed uniformly with loose fractured soil. When the seed is securely firmed into the surrounding soil, it will draw moisture easily for germination. The seed ‘passively’ absorbs moisture until the radicle (first root) emerges from the seed, which must quickly grow into the soil below the seed for the process to continue. Moisture loss to the atmosphere will be controlled by the mulch in the field, and the soil over the seed. Loose soil slows the rate of drying better than packed soil (for the science behind this, see our library article, Proper Seedbed Preparation. )

"Options For No-Till: If [standard] V closing wheels are used in wet soils, you can get severe compaction on both sides and prevent the roots from growing out of the seed trench. If pressure is reduced to prevent compaction, you won’t close the seed trench…Failing to press the seed and cover with loose material can lead to total stand failure. At best, it slows early growth and causes the plant to position its growing point improperly. No-tillers must add some type of seed lock mechanism (Keeton seed firmer or a seed lock wheel) to press the seed into the firm and moist soil at the bottom of the trench. Then some type of positive action must be used to cover the seed with loose soil and counteract the compaction and smearing that may have been done with the seed opener. A spoked wheel can chop up the edge of the seed trench and place some loose material over the top of the seed. This loose material keeps the seed zone from drying, allows oxygen exchange, and encourages warming in the area where the growing point will occur. Positive closing action is needed in wet and high residue situations. This is especially true for some soil types."
—Dwayne Beck, PhD, manager Dakota Lakes Research Farm, from several sources circa 1995 and compiled by Beck in 2005 for Exapta (he began stressing the need to approach seed pressing and covering differently in no-till systems as early as the 1980s). 

Successful no-till seeding begins with spreading the straw and chaff during the previous harvest. Large combines and wide swaths require aggressive technology to move the material out the full width of the swath. For some of the best, see Redekop Mfg