GOSSYPIUM HIRSUTUM L. بر پيدايش جوانه و رشد پنبه HELIANTHUS ANNUUS L. پتانسيل آلكوپاتيك بسمان هاي آفتابگردان

Allelopathic potential of sunflower (Helianthus annuus L.) residues on seed emergence and growth of cotton (Gossypium hirsutum L.)

It is known that sunflower produces allelopathic chemicals when in a rotation proceeds some other crops. This experiment was conducted to study the effect of sunflower residues on growth and yield of cotton. Fifteen treatments were compared in a Completely Randomized Block Design with four replications at the experimental station of the college of agricultural sciences, Sari, Iran. Fresh sunflower residues (from root, stem, leaf, leaf-stem, leaf-root, stem-root, and leaf-stem-root) were mixed in the soil at 8 and 16 percent ratios. Sunflower residues showed adverse effects on germination, height, dry weight and yield of cotton. There effects increased by increasing the amount of residues. Among treatmemts, root residues showed the least effect and the combination of root-stem-leaf had the most effect. Differences between the effect of leaf, root and stem were significant of 5% level. Differences among leaf-stem, leaf-root and root-stem were not siginficant. The results showed that residues of different prats of sunflower affect germination and growth of cotton. A reasonable time length is recommended between sunflower harvest and planting.