Location: Soil Dynamics ResearchTitle: Evaluation of organic spring cover crop termination practices to enhance rolling/crimping
|MCELROY, SCOTT - Auburn University|
|LI, STEVE - Auburn University|
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/9/2017
Publication Date: 5/9/2017
Citation: Price, A.J., Duzy, L.M., Mcelroy, S., Li, S. 2017. Evaluation of organic spring cover crop termination practices to enhance rolling/crimping [abstract]. ASA-CSSA-SSSA Annual Meeting Abstracts.
Technical Abstract: Cover crops provide valuable agronomic services in numerous production systems, especially in organic agriculture. With organic farming hecterage and cover crop interest increasing throughout the United States (U.S.), effectively timed cover crop termination practices are needed that can be utilized throughout the growing season. A two-year cover crop termination experiment was established in Alabama in fall, 2013. Four commercially available termination treatments were evaluated immediately following mechanical termination with a cover crop roller/crimper: 1) 20% vinegar solution, 2) 2.84 L/ha 45% clove oil/45% cinnamon oil mixture, 3) solarization using 0.15mm clear polyethylene sheeting with edges manually tucked into soil for 28 days over the entire plot, and 4) broadcast flaming emitting 1,100°C (approximately 7.3 million kj) applied at 1.2 km/h. A rolled/crimped alone treatment, and the synthetic herbicide glyphosate applied at 1.12 kg/ae ha, were included for comparison. Five cover crop species were evaluated: 1) hairy vetch (Vicia villosa Roth), 2) crimson clover (cv. Dixie; Trifolium incarnatum L.), 3) cereal rye (cv. Wrens Abruzzi; Secale cereale L.), 4) Austrian winter peas (Pisum sativum L.), and 5) rape (cv. Athena; Brassica napus L.). Three termination timings occurred at four week intervals beginning mid-March each year. In 2013, a maximum May biomass of 8,838 kg/ha was attained with cereal rye, followed by Austrian winter peas (7,177 kg/ha), hairy vetch (6,213 kg/ha), and crimson clover (5,124 kg/ha); rape provided the least biomass (1,657 kg/ha). Terminating covers in April resulted in approximately half biomass in all comparisons, while terminating covers in March resulted in less than 1,000 kg/ha regardless of cover species. Similar biomass trends were observed in 2014 although biomass totals were lower. Vinegar, along with clear plastic, had the highest costs driven by product costs and application rates; however, in general, it was not an effective termination method. While expensive, clear plastic was an effective termination method, however this practice requires additional labor and machinery time as compared to other treatments. Furthermore, there may be disposal costs associated with clear plastic, which were not accounted for in this analysis. The cost of flame termination was almost four times the cost of the glyphosate treatment; however, it proved to be an effective termination option for most covers evaluated. Organic producers needing to terminate winter covers would most likely be successful using a broadcast flamer for most winter covers or utilizing clear plastic for hairy vetch, winter peas, or cereal rye as ambient temperature increases along with solar radiation, both in combination with a roller/crimper. Commercially available vinegar and clove/cinnamon oil solutions provided little predictable termination and producers are likely to resort to tillage if no other material or practice is readily available.