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1 Nebraska COVER CROP Tuesday, Feb. 14, 2017 CONFERENCE at the Eastern Nebraska Research and Extension Center (located at the University s Agricultural Research and Development Center near Mead, Nebraska) The attached information was presented at the 2017 Nebraska Cover Crop Conference. Materials in this communication may be subject to copyright. Please contact the presenter/author of the materials for more information or for permission to reprint or reproduce content. Sponsored by: In partnership with: University of Nebraska Lincoln Institute of Agriculture and Natural Resources Extension is a Division of the Institute of Agriculture and Natural Resources at the University of Nebraska Lincoln cooperating with the Counties and the United States Department of Agriculture. University of Nebraska Lincoln Extension educational programs abide with the nondiscrimination policies of the University of Nebraska Lincoln and the United States Department of Agriculture.

2 2017 COVER CROP CONFERENCE Rodrigo Werle Nebraska Cropping Systems Specialist West Central Research and Extension Center Cover Crops Survey* *Survey conducted during the 2016 SMFD (>290 participants) 1

3 Cover Crops Survey* *Survey conducted during the 2016 SMFD (>290 participants) Figure credit: University of Illinois Extension Burndown + Residual Marestail / Kochia / Ragweed Waterhemp / Palmer amaranth POST + Residual Fall Burndown + Residual Marestail Start Clean, Stay Clean 2

4 Cover Crops as a Tool for Weed Management March 22, 2016 July 13, 2016 Cover Crops as a Tool for Weed Management Werle et al

5 Cover Crops as a Tool for Weed Management Werle et al Impact of Cover Crops on Weed Density 300 g m 2 = 2,670 lbs A -1 or 28 g ft 2 Teasdale et al. (1991) 4

6 Critical Period for Weed Control: Soybeans Critical time for weed removal Weed free Weed infested Keramati et al Shade Avoidance Study - Soybeans Red Far-Red Green-Tracewicz, Page, and Swanton

7 Shade Avoidance Study - Soybeans ± ± Green-Tracewicz, Page, and Swanton 2011 Shade Avoidance Study - Soybeans -36% -12% -7% -11% Green-Tracewicz, Page, and Swanton

8 Timing of Weed Control: Soybeans Yield loss occurring even though direct competition is not taking place Knezevic et al Shade Avoidance Study - Sugarbeets Kniss, A., weedcontrolfreaks.com 7

9 Start Clean McCook, NE bu/acre 64.6 bu/acre NO-PRE (6 WAP) GROUP 14+5 (6 WAP) Shade Avoidance Cover Crops Red Far-Red high R : FR low R : FR 8

10 Cover Crop Termination Time April May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. March April May June July Aug. Sept. Oct. VE V1 V3 V6 V9 VT R1 R6 VE V1 V2 V3 R1 R3 R6 R7 R8 April May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. March April May June July Aug. Sept. Oct. VE V1 V3 V6 V9 VT R1 R6 VE V1 V2 V3 R1 R3 R6 R7 R8 Cover Crop Termination 9

11 Cover Crop Termination: Herbicides Dr. Kevin Bradley 10

12 Dr. Kevin Bradley Influence of Glyphosate + 2,4 on Burndown of Cereal Rye Photo by Dr. Kevin Bradley, Univ. of Missouri 11

13 Herbicides are more effective when applied before the flowering (boot) stage. Dr. Kevin Bradley, Univ. of Missouri Roller/Crimper 12

14 Roller/Crimper Cereal rye control improved with cover crop developmental stage. Mirsky et al. (2009) Pennsylvania Roller/Crimper Photo by Keith Glewen 13

15 Green Planting Photos by Keith Glewen Green Planting Green planting Early terminated 14

16 Cover Crop Termination Study Early glyphosate burndown April 14 At-plant residual herbicide May 24 (Authority First + R-Up) May 4 (Cereal Rye/Combination = Chopped; Hairy vetch, nitro radish and no cover = tillage) Early post residual herbicide June 5 (Extreme) Roller/crimper May 20 Early post residual herbicide June 5 (Extreme) At-plant residual herbicide May 24 (Authority First + R-Up) Residue + Residual Herbicide = Good Weed Control! Miller and Werle, 2016 Regardless of Termination Strategies *WSSA Site of Action 15

17 Conclusions 16

18 THANK YOU! Follow us on 17