Ultra-Early Planting Effects on Maize Crop Development, Yield, and Weed Control

Abstract

Abstract Field experiments were conducted in 2001 and 2002 at the University of Thessaly Research Farm in Velestino, using three planting dates, namely: ultra-early (U-E, March 1 or 2), early (E), and normal (N) that were at least 2 weeks apart. Three maize hybrids were used: Eleonora, Pregia, and Constanza of 130, 123, and 125 day maturities, respectively. Maize emergence in the U-E planting was delayed by 8 days (19 DAP) compared with the N planting. Ear formation, fertilization and the black-layer appearance were always approximately 2 weeks ahead for the U-E compared with the other plantings. Although percentage emergence in the U-E was initially (at 4 WAP) the lowest, the final stands were similar (>94%) in either planting. Plant height and plant dry matter were lower at the U-E compared with the N planting. Only the hybrid Pregia showed the highest ratio below ground (BG) to above ground (AG) at all plantings. Leaf area index (LAI) at V6-V8 stage was highest in the N planting (differences were mainl...