Tillage effects on wheat emergence and yield at varying seeding rates, and on labor and fuel consumption

Conservation tillage systems can play an important role in reducing soil erosion and improving soil quality with the extra benefit of being equal to or more economical than conventional tillage; however, yield variability still remains a major concern among farmers. Field experiments were conducted in 2003 through 2004 and 2004 through 2005 in northern Greece to determine the effect of seeding rate (100, 150, 200, and 250 kg ha(-1)) on wheat establishment and grain yield under three tillage systems (minimum, reduced, and conventional tillage). In addition, labor time and fuel consumption for wheat production under these tillage systems were compared. For all tillage systems, the greatest number of wheat plants was recorded at the two highest seeding rates (P < 0.05). However, wheat plant numbers, averaged over seeding rates, were reduced by 1.1 to 17% in minimum tillage compared with conventional and reduced tillage systems in both growing seasons. Ear numbers were unaffected by tillage systems but generally increased with the increased seed rate. However, differences were not found in grain yield either among tillage systems or seeding rates. Regarding labor time and fuel consumption, 50 and 53% savings was achieved with minimum tillage, respectively, and 43 and 48% with reduced tillage in comparison with conventional tillage. These findings indicate that wheat can be grown successfully under conservation tillage systems with yields equal to those of conventional tillage and lower labor and fuel inputs. Increasing of seeding rate favored crop establishment in all tillage systems, but it did not provide any grain yield advantage.