Effects of density and relative time of pigweed (Amaranthus retroflexus) emergence on yield of potato (Solanum tuberosum)

Abstract

For create of food security is essential increasing of efficiency and more productivity strategic products such as potato. In order to investigate the effects of density and relative time of pigweed emergence on potato, a factorial field experiment was conducted during 2014 based on randomized complete block design with three replications at the Research Station of Borojen, Chaharmahal and Bakhtiari, Iran. Treatments were combination of three different pigweed densities (5, 10 and 15 plants/m2) and relative time of pigweed emergence (4 and 8 days before potato, emerged with potato, 4 days after potato emergence). Results indicated that the effects of density and relative time of emergence of pigweed was significant on number of branches per plant, plant height, number of tubers per square meter, biological yield and tuber yield of potato. Also, the interaction of between experimental factors was significant on the biological yield and tuber yield of potato. The earlier emergence and pigweed density led to reduce number of branches per node,biological yield and tuber yield and increase plant height of potato. The presence of weeds caused reduce the size and number of potato tubers. Procedure of decreasing biological yield and tuber yield potato was different with density increasing of pigweed in various relative time of emergence treatment. The highest (39.8 t ha-1) and the least (18.4 t ha-1) tuber yield were related to density of five plants/m2 and emergence at 4 days after potato and density of 15 plants/m2 and emergence at 8 days before potato treatments, respectively.