DIFFERENCE OF PRIMARY TILLAGE PRACTICES AS A FACTOR AFFECTING WHEAT GRAIN YIELD AND WEED BIOMASS UNDER DRY LAND FARMING IN NORTHERN IRAQ.

Abstract

Field experiment was carried out in Al – Nawaran field (35 km north Mosul city) and in the field of Agric & Forestry College , Mosul University (Northen Iraq) during growing season 2005 – 2006 to study the effect of different tillage system (Mold board plow + harrowing , Chisel plow + harrowing , Offset disk harrow and Zero tillage for two types ,of wheat (durm and soft grain)) on wheat yield and weed biomass .The experiment designe was RCBD with three replicates as asplit plote. The main plote was wheat types while the sub plote was tillage system. Result indicated that there was more weed number had seen at collge farm than Al– Nawaran and weed dry weight was increased up to 22,20% in soft than durm wheat at Al – Nawaran and college locations respectively. Less weed biomass had seen with the moldboad plow than other treatments . The differences between mold – board and zero tillage reach up 57.7,66.5 % in two locations respectively in spite of low grain yield was recorded at college farm , number of seeds / spike and grain yield was superier in soft than durm wheat . Moldboard plow at Al – Nawaran and moldboard or chesial at college location gave higher number of spik / m² , number of seeds /spike and higher yield ( kg/ha) .On other hand, less yield had recoerded with the zero tillage and the differences between moldboord and zero tillage in the grain yield was reached up to 23 , 63% at two locations, respectively .