Tillage system effects upon productivity of a dryland winter wheat–chickpea rotation in the northwest region of Iran

Abstract

Dryland winter wheat ( Triticum aestivum L.) is a major crop in the northwest region of Iran that is generally grown in rotation with 14-month fallow or chickpea ( Cicer arietinum L.). Information is limited on the success of more intensive dryland cropping systems with conservation tillage management. An experiment was conducted to determine the effect of five tillage systems on crop yield in a winter wheat–chickpea rotation during a 3-year period on a clay loam (Vertic Calcixerepts) in East Azerbaijan, Iran. The tillage systems consisted of moldboard plowing+disking as conventional tillage; chisel plowing+disking as reduced tillage; sweep plowing as minimum tillage; no tillage without and with previous crop residue. The highest wheat yield in three years was obtained with minimum tillage, whereas the yield of chickpea was greatest under no tillage with or without residue. Winter wheat or spring chickpea yield under no tillage with and without residues was not significantly different. Reduced-tillage wheat and chickpea yields were 14 and 27% higher than with conventional tillage, respectively. Average wheat grain yield with no and minimum tillage was significantly greater (27–31%) than under conventional tillage. No-tillage chickpea yield was significantly greater (24–57%) than under reduced, minimum or conventional tillage. The traditional system of moldboard plowing after wheat and chickpea could be replaced by conservation tillage systems that increase yield and will likely improve soil properties in the long term.