Optimum Height at Which to Kill Barley Used as a Living Mulch in Onions

Abstract

Planting barley (Hordeum vulgare L.) as a living mulch with onions (Allium cepa L.) reduces soil erosion and protects the onions from wind damage. It can also reduce yield and size of onion bulbs if not managed correctly. In a 4-year study at the Oakes Irrigation Research Site in North Dakota, barley was planted in the spring at the same time that onions were direct-seeded. Barley rows were planted either parallel with or perpendicular to the onion rows. Barley was killed with fluazifop-P herbicide when ≈13, 18, 23, or 30 cm tall. Onion size and yields were reduced when barley was allowed to grow taller than 18 cm before killing it. Total onion yield was usually greater when barley was planted parallel with, rather than perpendicular to, onion rows. Chemical name used: (R)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]propanoic acid (fluazifop-P).

Companion Crop and Planting Configuration Effect on Onion

“…Barley had been shown to be a good short-term companion crop for onion. Greenland (2000) reported that barley planted in rows parallel to the onion rows reduced soil erosion, protected onion from wind damage, and did not reduce onion size or yield as long as it was not allowed to grow taller than 18 cm. Results from the current study reinforce those of Greenland (2000), but also suggest that other planting or control methods should be investigated so that a longer application window is available in case of rainfall delays.…”

“…Greenland (2000) reported that barley planted in rows parallel to the onion rows reduced soil erosion, protected onion from wind damage, and did not reduce onion size or yield as long as it was not allowed to grow taller than 18 cm. Results from the current study reinforce those of Greenland (2000), but also suggest that other planting or control methods should be investigated so that a longer application window is available in case of rainfall delays. Canola provided good protection from wind damage, but by the time onion was at the required two-leaf stage for postemergence broadleaf herbicide applications, the canola was beyond the recommended size for control by bromoxynil and oxyfl uorfen.…”

Soil conservation practices for insect pest management in highly disturbed agroecosystems – a review

“…However, Boyd et al (2001) did not find any differences between potatoes grown with living mulches of hairy vetch, Marino red clover (Trifolium pratense L.), or Kentucky bluegrass (Poa pratensis L.) and potatoes grown on a bare ground. Similarly, barley did not decrease yield of onions if terminated prior to reaching 18 cm height (Greenland, 2000).…”

“…Abundance of flea beetles (Epitrix spp.) In onions, a living mulch of barley (Hordeum vulgare L.) was found to protect young onions from wind damage (Greenland, 2000). Potatoes planted into plots with herbicide-killed hairy vetch or winter rye (Secale cereale L.) likewise had lower Colorado potato beetle populations (Szendrei et al, , 2010.…”

“…Furthermore, aphid densities were frequently lower in crops incorporating living mulches (Costello & Altieri, 1995;Vidal, 1997;Hooks et al, 1998;Frank & Liburd, 2005), although no such data currently exist specifically for potatoes. In onions, a living mulch of barley (Hordeum vulgare L.) was found to protect young onions from wind damage (Greenland, 2000). Additionally, living mulches of various clover species reduced onion thrips populations in leeks (Allium ampeloprasum L.) (Weber et al, 1999).…”