Allelopathic influence of sunflower [electronic resource]: III- response of wheat and wheat weeds to allelopathic effects of sunflower residues under different nitrogen rates.

Includes references.

Two field experiments were conducted in a clay soil during 1998/99 and 1999/2000 seasons, at the Experimental Farm, Fac. of Agric., Tanta Univ., at Kafr El-Sheikh, Egypt, to determine the allelopathic influence of sunflower residues under different nitrogen rates on growth, grain yield and its components of wheat, as well as growth of wheat weeds. The experimental design was strip-plot with four replications. The horizontal plots were assigned to five treatments of sunflower residues (roots, stems, roots + stems, control and herbicide), while the vertical plots included three nitrogen rates (i.e., 60, 75 and 90 kg N/fed.). The main findinges could be summarized as follows: 1- Weeds: Ten annual weeds comprised a list of grass and broadleafweeds in wheat experimental area at 80 days after sowing in both seasons. Herbicide treatment and soil incorporation of sunflower roots, stems and roots + stems markedly decreased number of grass, broadleaf and total weeds/m 2, as well as fresh and dry weights of different weeds/m2 at 80 days after sowing, compared with the control treatment in the two seasons. Increasing nitrogen rate substantially suppressed weed density, as well as fresh and dry weights of total weeds in both seasons.

Summary in Arabic.

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