Tillage × maize hybrid interactions

Continuous maize (Zea mays L.) yields may be depressed with no-tillage (NT) compared with conventional chisel and disking systems (CD). Shallow or deep in-row tillage (ST and DT, respectively) may help alleviate this yield reduction, whereas some hybrids may be better adapted to NT. We therefore evaluated five maize hybrids with NT, ST, DT, and CD from 2002 to 2004 on a Hagerstown silt loam (fine, mixed, semiactive, mesic Typic Hapludalf) in southeastern Pennsylvania. Residue cover, penetration resistance, bulk density, and soil temperature were measured as well as maize emergence, mid-season height, and yield. Residue cover varied in the order NT > ST and DT > CD. Bulk density and penetration resistance in NT were higher than in ST, DT, and CD to the depth of tillage. In 2002, the average soil temperature dnring the first month after planting varied in the order NT < ST and DT < CD, but did not vary between tillage systems in 2004. Emergence was slower in NT than the other tillage systems in 2002 only. Emergence varied between hybrids, but there was no tillage × hybrid interaction. Mid-season maize height was not lower in NT than the other tillage systems. Tillage systems did not affect yield, and there was no tillage × hybrid interaction for yield, although some hybrids yielded better than others. The study suggests continuous maize yields with NT will be similar to tilled systems on well-drained soils in the northeastern USA and that tillage system is not important for hybrid selection.