Alternative weed control using the allelopathic effect of natural benzoxazinoids from rye mulch

In conventional agriculture, weed control by herbicides is an expensive practice and can also have a negative effect on the environment.\r\nAllelopathy permits sustainable weed management while reducing the impact of agriculture on the environment. We studied the\r\ncontent of 2,4-dihydroxy-1,4 (2H)-benzoxazin-3-one (DIBOA) and benzoxazolin-2(3H)-one (BOA), indicated as benzoxazinoids and considered\r\neffective for weed control, in 8 cultivars of rye and 1 of triticale grown in a greenhouse. We also tested the ability of mulches to inhibit\r\nthe germination of four warm-season weeds. Our results show that all rye cultivars produced DIBOA, while BOA was found only in four of\r\nthem. Benzoxazinoids were absent in triticale. Total benzoxazinoid content ranged from 177 to 545 μg g−1 and was statistically different among\r\ncultivars. Rye mulches were not able to suppress velvetleaf and common lambsquarters seedlings, while redroot pigweed and common purslane\r\nwere significantly affected. Weed suppression ranged from 40% to 52% for redroot pigweed and from 40% to 74% for common purslane. The\r\ninhibitory activity of triticale mulch was observed only for common purslane, with a suppression percentage of 33%. No correlation was found\r\nbetween total benzoxazinoid content and the number of weed seedlings suppressed, with R2 of 0.076 for redroot pigweed and R2 of 0.003 for\r\ncommon purslane, indicating that benzoxazinoids are not the only source of phytotoxicity.