ARS | Publication request: Effect of Cover Crop Extracts on Cotton and Radish Radicle Elongation

Submitted to: Communications in Biometry and Crop Science (CBCS)
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 3, 2008
Publication Date: July 1, 2008
Citation: Price, A.J., Stoll, M.E., Arriaga, F.J., Bergtold, J.S., Kornecki, T.S., Raper, R.L. 2008. Effect of Cover Crop Extracts on Cotton and Radish Radicle Elongation. Communications in Biometry and Crop Science (CBCS). 3(1):60-66.

Interpretive Summary: Research has shown that some cover crops possess properties that inhibit weed germination and growth. Additionally, negative effects have been documented in cash crops planted into cover crop residue. This study assessed the effects of cover crop extracts on radish and cotton root radicle elongation. The allelopathic potential of twelve cover crops on radish were evaluated using an extract-agar bioassay. Cotton was evaluated utilizing the same bioassay. All cover crop extracts inhibited radicle elongation compared to water. Differences among cover crops provide an additional tool for weed control in conservation systems; however, winter cover selection may also impact cash crop performance if producers plant into green residue.

Technical Abstract: Research has shown that some cover crops possess allelopathic properties that inhibit weed germination and growth. Additionally, negative allelopathic effects have been documented in cash crops planted into cover crop residue. This study assessed the effects of cover crop extracts on radish (Raphanus sativus L.) and cotton (Gossypium hirsutum L.) radicle elongation. The allelopathic potential of twelve cover crops on radish were evaluated using an extract-agar bioassay in two trials. Trial 1 cover crops included black oat (Avena strigosa Schreb.) cv. SoilSaver, crimson clover (Trifolium incarnatum L.) cv. AU Robin, white lupin (Lupinus albus L.) cvs. AU Homer and AU Alpha, rye (Secale cereale L.) cv. Elbon, wheat (Triticum aestivum L.) cv. Vigoro Grazer, and triticale (X Triticosecale Wittmack) cv. Trical 2700. Trial 2 cover crops included forage rape (Brassica napus L. var. napus) cv. Licapo, sunn hemp (Crotalaria juncea L.), Austrian winter field pea (Pisum sativum spp. arvense (L.) Poir), black medic (Medicago lupulina), hairy vetch (Vicia villosa Roth), black oat cv. SoilSaver, and crimson clover cv. AU Robin. Cotton was evaluated utilizing the same bioassay encompassing all mentioned covers in one trial (Trial 3). All cover crop extracts inhibited radicle elongation compared to water. Allelopathic potential is highly variable among cultivars within a cover crop species, and within a cultivar. Allelopathic differences among cover crops provide an additional tool for weed control in conservation systems; however, winter cover selection may also impact cash crop performance if producers plant into green residue.