Document Type : Research Paper

Authors

1 Agronomy/Crop Science/ Sari Agricultural Sciences and Natural Resources University

2 Agronomy, Crop Science, of Sari Agricultural Sciences and Natural Resources University

3 Sari Agricultural Sciences and Natural Resources University

Abstract

Weed infestation in arable lands is much more than one species, so it is important to pay attention to the interaction of multy species of weeds. To study the effect of redroot pigweed (Amaranthus retroflexus L.) and barnyardgrass (Echinochloa crus-galli (L.) P. Beauv) interference on yield and essential oil of fennel (Foeniculum vulgare Mill.), an experiment was done in Research field of Sari Agricultural Sciences and Natural Resources University in 2017. Experiment was arranged in a factorial arrangement based on randomized complete block design with three replications. Experimental factors included three densities of redroot pigweed (0, 4 and 8 plants m-2) and three densities of barnyardgrass (0, 4 and 8 plants m-2). The highest grain yield (2230 kg ha-1) and essential oil content (2 %) were obtained at weed free plots. The density of 8 redroot pigweed plants m-2 at simultaneous interference with 0, 4 and 8 barnyard grass m-2 decreased grain yield by 30.1%, 62.9% and 75.7%, and essential oil content by 24.5%, 26.2% and 29.5% compared with weed free plots, respectively. The coefficient of redroot pigweed competitivity was predicted higher than barnyardgrass, and the interference of 14.5 barnyardgrass plants m-2 or 7.7 redroot pigweed plants m-2 decreased fennel grain yield by 50 percent.

Keywords