Early-planted and high-residue environments tend to experience considerable emergence stress - particularly in cool, wet springs.
To maximize emergence, research shows it's best to avoid planting until soil temperatures are anticipated to be 50 degrees or more and preferably with a near-term warming trend. Studies show decreased emergence rates with cooler soils or when an extended cold front moves in after planting.
Imad Saab, Pioneer research scientist, says growers should monitor soil temperatures at planting depth. In addition to waiting for soils to warm, he suggests customers try to delay planting until the soil is dry enough to minimize compaction issues. These practices help protect against stand and yield loss.
Growers who practice no-till or minimal tillage need to be aware of added stress from these environments. High residue can lead to cooler soils, physical barriers to seedling emergence and uneven planting depth.
All of these factors may reduce stand uniformity or increase the opportunity for "runt plants" - plants that are out competed by their neighbors. Non-uniform stands can suffer significant yield losses because runt plants often produce little or no yield. Saab says growers may see "runt plants" for the following reasons:
To combat these issues, Pioneer offers hybrids with high-residue suitability scores and strong stress emergence scores. Row cleaners on the planter may also help lessen the effects of heavy residue. Higher rates of insecticide seed treatments also can help mitigate stress from early-season insects.
Corn Stress Emergence