URBANA Although advances in agronomy, breeding, and biotechnology have dramatically increased corn grain yields, soil test values indicate that producers may not be supplying optimal nutrient levels. Moreover, many current nutrient recommendations, developed decades ago using outdated agronomic management practices and lower-yielding, non-transgenic hybrids, may need adjusting.
Researchers with the University of Illinois Crop Physiology Laboratory have been re-evaluating nutrient uptake and partitioning in modern corn hybrids.
"Current fertilization practices may not match the uptake capabilities of hybrids that contain transgenic insect protection and that are grown at planting densities that increase by about 400 plants per acre per year," said U of I Ph.D. student Ross Bender. "Nutrient recommendations may not be calibrated to modern, higher-yielding genetics and management."
The study examined six hybrids, each with transgenic insect protection, at two Illinois locations, DeKalb and Urbana. Researchers sampled plant tissues at six incrementally spaced growth stages. They separated them into their different fractions (leaves, stems, cobs, grain) to determine season-long nutrient accumulation, utilization, and movement.
Although maximum uptake rates were found to be nutrient-specific, they generally occurred during late vegetative growth. This was also the period of greatest dry matter production, an approximate 10-day interval from V10 to V14. Relative to total uptake, however, uptake of phosphorus (P), sulfur (S), and zinc (Zn) was greater during grain fill than during vegetative growth. The study also showed that the key periods for micronutrient uptake were narrower than those for macronutrients.
"The implications of the data are numerous," said Matias Ruffo, a co-author of the paper and worldwide agronomy manager at The Mosaic Company. "It is necessary that producers understand the timing and duration of n
|Contact: Susan Jongeneel|
University of Illinois College of Agricultural, Consumer and Environmental Sciences