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Title: High Residue Winter Cover Crops Deplete Winter Annual Weed Seed Across a Landscape in a Long-Term Tillage Study

item Price, Andrew
item Arriaga, Francisco
item Balkcom, Kipling
item Raper, Randy

Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 2/2/2009
Publication Date: 2/2/2009
Citation: Kelton, J., Van Santen, E., Shaw, J., Price, A.J., Arriaga, F.J., Balkcom, K.S., Raper, R.L. 2009. High Residue Winter Cover Crops Deplete Winter Annual Weed Seed Across a Landscape in a Long-Term Tillage Study [abstract]. Weed Science Society of America Meeting Abstracts.

Interpretive Summary:

Technical Abstract: High residue conservation agriculture systems have the potential to maximize environmental benefits achieved when practicing reduced tillage. A greenhouse study was conducted in 2006 through 2008 to determine the effects of cover crop residue on weed seed density within the soil seedbank under varying farming practices and topographical conditions. In mid-October, 2006, soil samples were collected from an on-going field-scale study located at the E.V. Smith Research and Extension Center, Alabama, USA. A factorial arrangement of the experiment included conventional and conservation tillage, with and without manure applications, under a cotton-corn rotation with both crops present during the growing season. Landscape positions identified as treatments included summit, backslope, and drainage way. Cover crops included a crimson clover, fodder radish (Raphanus sativus L.), and white lupin (Lupinus albus L.) mix preceding corn and a rye-black oat mixture preceding cotton in the conservation tillage plots. Covers were planted in late fall; termination of the clover, radish, and lupin cover occurred in mid-March; termination of the rye-black oat cover occurred in mid-April. Six replications were made in the field and subsequently divided into equal cells with 3 replications of each treatment grouping being sampled for this study. Soil cores, five from each cell, were divided into an upper (0-0.076m) and lower (0.076-0.152m) sample, pooled together to create one sample of each level within a replication. Samples were placed in the greenhouse, allowed to germinate, and seedlings were identified until germination ceased at approximately five months. Samples were then chilled at 36°F to five months and the process repeated two additional times. Weed seed density consisted of over 80 % henbit (Lamium amplexicaule L.) throughout the experiment. Data analysis found that weed seed density was decreased in conservation tillage when compared to conventional tillage at both the upper and lower soil levels. Additionally, density of the seedbank was reduced in the upper soil portion of no-till cotton with rye-oat cover in comparison with no-till corn plots with the clover-radish-lupin cover. These findings indicate that high residue cover crops could be incorporated into farming systems as an effective aid in suppressing winter weed seed germination.