مطالعه پويايي جمعيت علف هاي هرز با اعمال مديريت بقاياي گياهي و تقسيط كود نيتروژن در زراعت گياه كلزا

The Study of Dynamics of Weed Plants Population Affected by Residue Management and Nitrogen Splitting Implanting of Canola

In order to study the effect of crop residue management (C.R.M) and nitrogen splitting (N-splitting) methods on yield and yield components of canola, a filed experiment was conducted in Research Station of Shahid Chamran University in 2005-2006, 2006- 2007 (first year wheat, second year canola). The experiment was set up in a split plot design with three replications. The main plot treatments were C.R.M (i.e. incorporation, removal and burning the wheat residue) and sub plot treatments were N-splitting with combination of nitrogen- based and top dressing of nitrogen applied at three levels (i.e. 50+50, 25+75 and 25+50+25 %). The measurement of plant characteristics, plant density and sum of dry matter of weeds were used to evaluate plant growth and standing within canola population. The results indicated that weed plants greatly declined regardless of type of weed species, when the plant residues were incorporated into the soil. Further reduction could significantly inhibit weed growth and nitrogen source applied in form of N-splitting (50+50%). Findings also showed that the highest (19.4 plant/m2) and lowest (5.1 plant/m2) weed plants were observed under burning the residues treatment receiving 25+75 % N- splitting and incorporation of the residue treatment receiving 25+50+25 % N- splitting respectively; The highest (153.8 g/m2) and lowest (43.2 g/m2) yield production of dry matter of weed populations were accumulated when the residues were burned and received 25+75 % N- splitting incorporated and receiving 25+50+25 % N-splitting respectively, in the present study, the evidence indicated a desirable method of crop residue management when incorporating the residues in form of N- splitting (50+50 %).