Abstract
In a rice-wheat system, rice stubbles remaining in the field often delay early planting of winter wheat to utilize residual soil
moisture and reduce operating costs. A randomized complete block design in a split plot arrangement was conducted with
four seasonal tillage methods [conventional tillage, CT; deep tillage, DT; zero tillage with zone disk tiller, ZDT; and happy
seeder, HS] as main plots and five N levels [0, 75, 100, 125, and 150 kg ha-1
] as subplots during 2009 to 2010 and 2010 to
2011 wheat growing seasons. Results showed that DT significantly decreased soil bulk desnsity, penetration resistance, and
volumetric moisture content compared with CT, ZDT and HS. However, wheat growth and yield parameter such as fertile
tillers, plant height, root length, spike length, grain yields, and water and nutrient-use efficiency was significantly higher in
DT compared with other tillage treatments. Wheat growth and yield was more increased by N fertilization at 125 kg ha-1
than
other N rates. However, when the wheat plant productivity index was plotted over N rates, the non-linear relationship showed
that N fertilization at 80 kg N ha-1
accounted for 85% of the variability in the plant productivity under DT and HS while ZDT
had the same productivity at 120 kg N ha-1
.
