Location: Crop Protection and Management Research
Title: Systems to manage perennial weeds in organic transitions Author
Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 6, 2010
Publication Date: February 8, 2011
Citation: Johnson, W.C. 2011. Systems to manage perennial weeds in organic transitions[abstract]. Weed Science Society of America Meeting Abstracts. 51:254. Technical Abstract: There is increased interest in the southeastern U. S. to produce certified organic agronomic crops, including peanut. Many conventional growers are interested in diversifying into organic production by using long-term fallow sites (non-improved pastures, old hayfields, or abandoned crop producing fields) and having these sites immediately certified as organic. However, common bermudagrass frequently infests long-term fallow sites and is extremely difficult, if not outright impossible, to control in organic crop production systems. Research trials in a site heavily infested with common bermudagrass were conducted from 2008 to 2010 to evaluate systems of perennial weed control during fallow organic transition. Treatments evaluated were all possible combinations of two primary tillage implements (power spader, disk harrow), summer weed control (solarization, fallow tillage with a peanut digger, and non-treated control), and winter tillage (fallow tillage with a peanut digger and non-tilled control). Weed control parameters were measured the following spring, ten months after trial initiation. Common bermudagrass densities were reduced by combinations of summer solarization or summer tillage with a peanut digger, followed by winter tillage with a peanut digger. The peanut digger displaced common bermudagrass and exposed the vegetative material to desiccation. However, control was not sufficient enough to prevent re-infestation by survivors. Perennial nutsedges were present, but at non-uniform densities. Primary tillage with a power spader reduced yellow and purple nutsedge tuber densities compared to the disk harrow. Tuber densities were also reduced by summer tillage with a peanut digger. These results indicate that an integrated system of summer solarization or summer tillage with a peanut digger, followed by winter tillage with a peanut digger reduce densities of common bermudagrass. However, using systems of this type for only one season are not effective and the weed will repopulate. Further validation on sites with uniform densities of perennial nutsedges is needed before response of those weeds to weed control treatments can be determined.