Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 30, 1999
Publication Date: N/A
Interpretive Summary: Mulch soil cover generally improves the yield of cotton when it is grown using conservation tillage techniques. Cereal cover crops, such as wheat, rye, and oat, can be grown over the winter months to provide the mulch cover. Black oat (Avena strigosa) is used as a winter cover crop on millions of hectares of land in Brazil and Paraguay. We were interested in ndetermining the potential of black oat as a winter cover crop for cotton i the southeast USA and our study was designed to compare this species to wheat, rye, and oat as cover crops for cotton. Black oat was higher in nitrogen concentration than any of the other three species of winter cereals. It produced as much growth as wheat did, but did not always grow as much as oat and rye did. There was no difference in cotton yield when black oat, wheat, and oat were the cover crops, but cotton grown following black oat had higher yield than cotton following rye. Overall, black oat may become an acceptable cover crop for the growers in the southeast, but evaluations of other cultivars and/or improvement programs to improve cold-hardiness are needed to make this species more reliable. These data are important to scientists, NRCS, and extension personnel developing conservation tillage systems for southeastern USA farmers.
Technical Abstract: Black oat (Avena strigosa Schreb.) is the predominate cereal cover crop for millions of ha of cash crops in southern Brazil and Paraguay. However, no information is available on the suitability of black oat as a cover crop for cotton (Gossypium hirsutum L.) in the southeastern USA. The objective of this study was to compare black oat to adapted winter cereals for this region and to determine the effect of cereal residue species on cotton growth, N status, and yield. In a greenhouse study in which cereal residues were mixed with soil, black oat residue inhibited tap root elongation of both cotton and radish (Raphanus sativa L.) more than rye (Secale cereale L.) residue. In a two-year field experiment on a Goldsboro loamy sand (fine-loamy, siliceous, thermic Aquic Kandiudult), cotton was grown following winter covers of black oat, oat (Avena sativa L.), rye, and wheat(Triticum aestivum L.) that were planted at three different times in the fall (October, November, and December). Black oat had the same biomas production as the other cereals in all planting dates in the first year of the study. In the second year, a low temperature of -12.2 deg C occurred during the winter. Black oat was comparable to wheat in all planting dates but was lower than rye for all three planting dates and lower than oat in the October planting date in that year. Black oat tended to have a higher N concentration than the other cereal species. Cotton plant density was lowest following black oat and rye. Cotton growth and N status were more dependent on residue amount than on residue species. Lint yield for the cotton following black oat was 120 kg/ha higher than that following rye. Black oat has potential as cover crop for cotton in the southeastern USA.