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Title: Multiple rolling/crimping effects on termination of two summer cover crops in a conservation system

item Kornecki, Ted

Submitted to: Southern Sustainable Agriculture Working Group, SAWG
Publication Type: Abstract Only
Publication Acceptance Date: 1/27/2016
Publication Date: 1/27/2016
Citation: Kornecki, T.S. 2016. Multiple rolling/crimping effects on termination of two summer cover crops in a conservation system. Southern Sustainable Agriculture Working Group, SAWG. CDROM.

Interpretive Summary:

Technical Abstract: A field experiment was initiated in the 2015 growing season at the USDA-NSDL to determine the effectiveness of a prototype two-stage roller/crimper in mechanical termination of two summer cover crops intended for organic systems. The experiment was a randomized complete block design with four replications for each treatment. On June 3rd, 2015, two Soil Bins (20’ x 250’ area) at the NSDL were hand seeded with pearl millet (Pennisetum glaucum), at rate 61 lbs/acre, and a legume iron clay pea (Vigna unguiculata) at rate 113 lbs/acre. Pearl millet produced 12527 lbs/acre and iron clay pea produced 7048 lbs/acre of biomass and were terminated with the two stage roller/crimper on August 14 and 28, 2015, respectively. Plots with both cover crops were rolled/crimped once (Treatment 1), twice (treatment 2) and three times (treatment 3). Standing covers were used as the control (treatment 4). Termination rates were evaluated one, two, and three weeks after rolling. In addition, to determine the effect of multiple rolling over the same area on soil compaction, soil strength was also measured at the center of each plot and on the tractor’s wheel track. Results show that rolling three times provided significantly higher termination rates for both cover crops compared with rolling once or twice during a three week evaluation period. Three weeks after rolling, termination rate for pearl millet rolled 3 times was 100% compared to 95% rolled once, 92% rolled twice, and 49% for the control. For iron clay pea 3 weeks after rolling, termination rate for rolled 3 times was 97% compared to rolled twice, 71%, rolled once, 36% and for the control 7%. An increased amount of regrowth for both crops was observed for rolled once and twice compared to rolled 3 times. Examining soil compaction during the evaluation period showed no significant increase in soil compaction for rolled two times (1.9 MPa) and three times (2.1 MPa) for iron clay pea. The soil strength at tractor’s wheel traffic rolled twice or 3 times did not generate higher values than for rolled once or for both standing cover crops. Occasional increases in soil strength (compaction) were related to hardpans that already existed in the soil profile prior to conducting this experiment. Soil strength for pearl millet was lower than for iron clay pea due to different soil type (clay vs. loam) and higher moisture. Based on one year of data, rolling/crimping of pearl millet and iron clay pea three times showed promising termination rates and should be considered a feasible alternative to chemical herbicides in managing summer cover crops in organic production systems in the Southeast.