Search

A field trial was conducted in Domokos region, in central Greece with Helianthus annuus, hybrid 'LG 5658' in order to evaluate the effects of different N fertilization and weed control methods on sunflower yield and weed flora. ANOVA showed that the interaction of fertilization and weed control had a significant effect on grain yield. Moreover, this study revealed that the density of the common weeds Amaranthus retroflexus, Abutilon theophrasti, Xanthium strumarium and Echinochloa crusgalli was increased by 60, 40, 33 and 23% in the plots of high N rate without any herbicide use. On the contrary, weeds like Datura stramonium and Convolvulus arvensis were not significantly affected by fertilization. This different responsiveness of the several weed species could be further exploited through programs of integrated crop and weed management. Moreover, our findings related to the differences in herbicide efficacy resulting from different N levels may alter weed flora and explain possible weed control failures. [ABSTRACT FROM AUTHOR]

Environmental concerns and several adverse effects of reliance on and improper use of pesticides make necessary the use of alternative methods. Allelopathy has a rather unexploited potential in integrated weed management and ought to be further studied. The allelopathic effects of velvet bean (Mucuna pruriens (L.) DC. var. utilis) on seedling emergence and first growth of the important weed rigid ryegrass (Lolium rigidum L.) were evaluated in a pot experiment conducted at Agricultural University of Athens. Leaf residues of velvet bean were used to determine their inhibitory potential on seedling emergence and growth parameters including height, leaf number, tillering and fresh and dry weight of rigid ryegrass. Moreover, the allelopathic potential of inflorescence residues of chia (Salvia hispanica L.) on rigid ryegrass was also evaluated. Our results revealed a significant weed suppressive ability of the studied plants. The plant residues incorporated into the soil significantly reduced the seedling emergence and growth parameters of rigid ryegrass as compared to the control. In particular, velvet bean's residues also reduced height, leaf number and biomass of rigid ryegrass up to 26, 51 and 62%, respectively. The indicated allelopathic activity of velvet bean and chia could be further exploited in future studies, by using either allelochemicals as models for future herbicides or the plants as useful cover crops or mulches in terms of integrated weed management. [ABSTRACT FROM AUTHOR]