Much of wheat’s yield potential is determined by how early and uniformly the seedlings emerge. Michigan State University Extension suggests noting the differences within and between fields may help fine-tune your planting practices.
Fall 2017 was particularly difficult to have all seedling emergence relatively uniformly due to dry conditions. Particularly where seed was broadcasted over soybeans or sown in dry soils during September, some fields exhibited a significant delay in seed and seedling development until rain finally arrived on the weekend of Oct. 14-15.
In most cases, enough viable seed was still able to produce reasonably good stands, but emergence in these fields may have occurred over a couple weeks’ time. This will mean seedlings will be at different developmental stages this fall and throughout the 2018 season.
The timing of future applications of herbicide, growth regulators and fungicides, especially for Fusarium head scab, should key on the most mature plants in the field except where the younger plants greatly outnumber the early-emerged seedlings.
Uniform plant densities
Gaps and uneven growth within a stand should be noted, as well as any obvious causes such as crop residue, traffic or drill performance, so corrective action can be taken before next fall. Also, make note of unhealthy pockets of seedlings and attempt to diagnosis the problem. Particularly if the roots appear discolored, seedlings could be mailed to MSU Diagnostic Services.
Submitting soil samples to a soil analysis laboratory could also be helpful; collect soil from the poor area and from an adjacent good area to aid in diagnosis.
It is worthwhile to determine the number of seedlings per foot of row—this exercise is much easier if performed prior to extensive tillering. Generally, early planted wheat would have 14 to 20 plants per foot of row (7.5-inch row spacing), whereas you might aim for 22 or more seedlings where sown in mid-October.
Knowing the number of seedlings per foot of row is useful in determining how closely it aligns with the intended seeding rate and drill setting. The table below can serve as a reference.
For example, if you feel you were dropping 1.8 million seeds per acre (26 seeds per foot of row), but find an average of less than 20 seedlings per foot, it would be worthwhile to determine the reason. In some cases, it might be due to an over-estimation of seeding rate.
In other situations, it may be associated with difficulties in germination or emergence.
|Comparing actual seedlings population to seeding rate.|
|Seeding rate (millions/ac)||Seeds per foot of row*||Seedlings per foot of row**|
* Target seeding rate/43,560 X 0 .625 = seeds per foot of row (7.5-inch spacing).
** Average number of seedlings (assumed emergence rate in parentheses).
Confirming actual seed depth placement can also be worthwhile. The actual depth can be determined by simply digging up the seed or measuring the distance between the seed and the crown. Where the seed is next to the crown, you can surmise that the seed was placed a half-inch or less below ground. Where a mesocotyl is visible between the seed and crown, its length plus another half-inch approximates the seed’s original depth.
Generally, the goal is to have wheat planted early enough so there is sufficient warm weather for the main shoots to develop a couple of tillers. This stage of growth suggests the plant has a well-developed root and shoot system for winter survival and for taking full advantage of the next spring’s growing environment.
You should also note any weeds that have emerged, particularly winter annuals that emerge this fall. Horsetail, a strong candidate for enemy No. 1 among weeds in Michigan, can emerge in fall or spring. If horseweed is present or anticipated, develop a strong herbicide program to keep this weed in check. In the future, if you want to use red clover as a cover crop, you may need to key on fall herbicide treatments.
Obviously, these evaluations are most constructive if you create a record for each field. This record would at least include variety, seed size and drill settings. It is also a good idea to save a seed tag that includes lot number and seed characteristics. Lastly, remember that the Farm Service Agency acreage report deadline for fall-planted small grains acreage is Nov. 15, 2017.