Submitted to: Agronomy Journal
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/28/2005
Publication Date: 10/19/2005
Citation: Gesch, R.W., Archer, D.W. 2005. Influence of sowing date on emergence characteristics of maize seed coated with a temperature-activated polymer. Agronomy Journal. 97:1543-1550. Interpretive Summary: The growing season for corn in the northern Corn Belt is short compared to regions further south. Because of cold, wet springs often experienced in the upper Midwest, the period of time to plant corn in order to achieve maximum yields is very short. Farmers in the northern Corn Belt are generally encouraged to plant corn about the last week in April to early May. However, if corn is planted too early when the soil temperature is at or below 50 deg F, and sits in the ground too long before germinating, the seed can rot or be weakened leading to poor stand establishment. On the other hand, if planted too late the farmer suffers yield loss because the corn does not have enough time to properly mature. Recently, a polymer-based coating (i.e. a biodegradable plastic-type coating) has been made that can be used to coat corn seed and protect it from the environmental hazards of early planting. This new management tool potentially can take some of the risk out of planting corn early and be a big benefit to farmers. Our research, which was done over a three-year period, shows that polymer-coated corn seed can be planted earlier than normal (about two to four weeks), while reducing the risk of poor stand establishment caused by cold, wet soils. Planting corn earlier than normal can allow farmers more time in the spring to get their field work done in a timely manner. Also, early-planted corn has the advantage of using the full growing season to mature.
Technical Abstract: Cold, wet soils coupled with a short growing season, tend to create a narrow window of optimum time for planting corn (Zea mays L.) in the northern Corn Belt. A technological advance in seed coating using a polymer whose physical structure changes abruptly with temperature, may offer potential for planting corn exceptionally early. Temperature-activated polymer (TAP) coatings can inhibit planted seed from imbibing water until adequate soil temperatures are reached to promote germination and emergence. A three-year study was conducted in west central Minnesota on a Barnes soil to determine the potential for earlier-than-average planting of TAP-coated corn seed. The objective was to compare emergence characteristics of coated and uncoated hybrid corn planted early and at a near average time. The primary hypothesis tested was whether maximum emergence and stand uniformity of TAP-coated seed planted early under cold soils is comparable to uncoated seed sown later under more favorable soil temperatures. In two of the three years, earliest planted seed (as early as 29 Mar in 2000) remained in the soil for as long as 26 to 32 d before emerging. In these instances, stands from TAP-coated seed, which ranged from 60 to 90% of seed planted, were generally significantly greater than those of uncoated seed, which ranged from 49 to 68%. In regard to stand establishment and time required to obtain 50% and from 10 to 90% emergence, most early-planted coating x hybrid combinations performed as well as uncoated controls planted later at a near average time. Results of this study indicate that TAP coating technology shows promise as a management tool for early corn planting.