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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 How to Incorporate Cover Crops Early Maturing Hybrids and Varieties Roger W. Elmore Agronomy & Horticulture Extension Cropping Systems Agronomist Heuermann Chair With cooperation of: Angela Bastidas Chris Proctor Kaylee Cowan Agronomy & Horticulture How to Include Cover Crops in Cropping Systems Using different corn planting dates and hybrid maturities Delay cover crop termination by planting late cash crop Planting cover crops after corn harvest (using earlier hybrids) January February March April May June July August September October November December 1

3 Literature: Corn Yield as affected by population Plant density (x1000 plants ha -1 ) Assefa, Y., P. V. Vara Prasad, P. Carter, M. Hinds, G. Bhalla, R. Schon, M. Jeschke, S. Paszkiewicz, and I.A. Ciampitti Yield responses to planting density for US modern corn hybrids: A synthesis-analysis. Crop Sci. 56(5): Literature: Corn Yield as affected by population Assefa, Y., P. V. Vara Prasad, P. Carter, M. Hinds, G. Bhalla, R. Schon, M. Jeschke, S. Paszkiewicz, and I.A. Ciampitti Yield responses to planting density for US modern corn hybrids: A synthesis-analysis. Crop Sci. 56(5):

4 Literature: Corn Yield as affected by population High Environment Medium Environment Plant density (x1000 plants ha -1 ) Assefa, Y., P. V. Vara Prasad, P. Carter, M. Hinds, G. Bhalla, R. Schon, M. Jeschke, S. Paszkiewicz, and I.A. Ciampitti Yield responses to planting density for US modern corn hybrids: A synthesis-analysis. Crop Sci. 56(5): Study 2: Finding the balance between corn yield and cover crop biomass Objectives 1. Understand the effects of planting date, corn maturity and plant population on corn yield. 2. Evaluate cover crop biomass production as affected by the different planting dates after corn is harvested. 3. Identify the impact on rotational crop (Soybean) 3

5 Study 2: Finding the balance between corn yield and cover crop biomass Methods Two research sites: SCAL (irrigated) for 2015 and 2016, Havelock (rain-fed) for 2016 Designs: Corn: Split-plot with four replications, whole plot for planting date and sub-plots for the factorial combination of corn maturity x plant population Cover Crop: RCBD with four replications of rye planting dates (drilled) No-till, region-specific fertilization and weed control Study 2: Finding the balance between corn yield and cover crop biomass Corn Hybrids: Product Name Transgene Trait CRM 1 GDU 2 to Mid-Silk GDU 2 to Black Layer 2015 DKC30-19RIB VT Double Pro Refuge in the bag DKC35-55 VT Triple Pro DKC42-36RIB SmartStax Refuge in the bag DKC45-65RIB SmartStax Refuge in the bag DKC47-35RIB SmartStax Refuge in the bag Mycogen 2V717 SmartStax Refuge in the bag DKC65-79RIB SmartStax Refuge in the bag DKC30-19RIB VT Double Pro Refuge in the bag STXRIB SmartStax Refuge in the bag DKC42-36RIB SmartStax Refuge in the bag DKC45-65RIB SmartStax Refuge in the bag STXRIB SmartStax Refuge in the bag DKC55-20 RIB SmartStax Refuge in the bag DKC61-54RIB SmartStax Refuge in the bag STXRIB SmartStax Refuge in the bag Comparative Relative Maturity 2 GDU Calculated from date of planting, heat accumulation starting at 10 o C 4

6 Study 2: Finding the balance between corn yield and cover crop biomass Weather Conditions at SCAL Mean Tmean ( o C) (May 1st to Sep 30th) Annual Precip (mm) Irrigation (mm) Mean Tmean ( o C) (May 1st to Sep 30th) Annual Precip (mm) Irrigation (mm) Study 2: Corn Yield Results SCAL Combined Years Effect DF Pr > F block(year*pd) ns year ns pd ns year*pd ns rm 4 <.0001 ** year*rm * pd*rm 4 <.0001 ** year*pd*rm ns pop ns year*pop ns pd*pop ns year*pd*pop ns rm*pop ns year*rm*pop ns pd*rm*pop ns year*pd*rm*pop ns Residual 152 * Significat at P 0.05 ** Significat at P 0.01 ns nonsignificant Corn yield as affected by planting date and relative maturity at SCAL (irrigated) across both years (2015 & 2016). Bars with the same letter(s) within same planting date are not different (Significant at P 0.05). 5

7 Study 2: Corn Yield Results SCAL Combined Years Corn yield as affected by year and relative maturity at SCAL. Bars with the same letter(s) within same year are not different (Significant at P 0.05). Corn yield as affected by relative maturity at SCAL across both years (2015 & 2016). Bars with the same letter(s) are not different (Significant at P 0.05). Study 2: Corn Yield Results SCAL Individual Year Effect DF Pr > F DF Pr > F pd ** ns rm 6 <.0001 ** 7 <.0001 ** pd*rm 6 <.0001 ** ** pop * ns pd*pop ns ns rm*pop * ns pd*rm*pop ns ns Residual * Significat at P 0.05 ** Significat at P 0.01 ns nonsignificant Summary of statistical results for interaction and treatment effects of individual year (7 relative maturity hybrids for 2015 and 8 relative maturity hybrids for 2016). 6

8 Study 2: Corn Yield as affected by planting date and maturity at SCAL Bars with the same letter(s) within same planting date are not different (Significant at P 0.05). Study 2: Corn Yield as affected by population and maturity at SCAL Bars with the same letter(s) within same population are not different (Significant at P 0.05). 7

9 Study 2: Biomass Results (2015) at SCAL Year 1 Fall 2015 Spring 2016 Effect DF Pr > F Pr > F block ** 0.6 ns pd 3 <.0001 ** <.0001 ** Residual 33 * Significat at P 0.05 ** Significat at P 0.01 ns nonsignificant Planting Date Cover Crop Biomass (lb acre -1 ) Fall Spring a b b c a b bc c 2-Oct 9-Oct 12-Oct 21-Oct Corn Harvest 80 RM 95 RM (Early) 95 RM (Late) 111 RM (Early) 86 RM 115 RM (Early) 92 RM Fall and Spring biomass production as affected by the planting date at SCAL (irrigated) and estimated corn RM harvest maturities. Bars with the same letter(s) within same sampling are not different (Significant at P 0.05). Sampling dates: 12/08/2015 and 04/14/2016 (Year1). Linear regressions were also significant (P 0.001). Study 2: Biomass Results (2016) at SCAL Effect DF Year 2 Fall 2016 Pr > F block ns pd 5 <.0001 ** Residual 15 * Significat at P 0.05 ** Significat at P 0.01 ns nonsignificant Planting Date Cover Crop Biomass (lb acre -1 ) a b bc c c c 22-Sep 30-Sep 6-Oct 13-Oct 20-Oct 27-Oct Corn Harvest 80 RM Early 80 RM Late 95 RM Late 105 RM Late 111 RM Early 111 RM Late 86 RM Early 86 RM Late 99 RM Late 115 RM Early 115 RM Late 92 RM Early 92 RM Late 105 RM Early 95 RM Early 99 RM Early Fall biomass production as affected by the planting date at SCAL (irrigated) and estimated corn RM harvest maturities. Bars with the same letter(s) are not different (Significant at P 0.05). Sampling date: 11/15/2016 (Year 2). Linear regression is also significant (P 0.001). 8

10 Study 2: Rye biomass as affected by planting date at SCAL 2-Oct 21-Oct 21-Oct 2-Oct Fall Sampling (12/8/2015) Spring Sampling (04/14/2016) Study 2: Finding the balance between corn yield and cover crop biomass Weather Conditions at Havelock: Mean Tmean ( o C) (May 1st to Sep 30th) Annual Precip (mm)

11 Study 2: Corn Yield Results Havelock (2016) Effect DF Pr > F block(pd) ns pd 1 <.0001 ** rm 7 <.0001 ** pd*rm * pop ns pd*pop ns rm*pop ns pd*rm*pop ns Residual 89 * Significat at P 0.05 ** Significat at P 0.01 ns nonsignificant Corn yield as affected by planting date and relative maturity at Havelock (rain-fed) in Bars with the same letter(s) within same planting date are not different (Significant at P 0.05). Study 2: Finding the balance between corn yield and cover crop biomass Preliminary Conclusions Shorter-season hybrids, 95 and 105 RM, compared to the regionally used, 111 RM or higher, may allow earlier corn harvest and cover crop planting without negatively impacting corn yield and ultimately increase cover crop biomass production. The 80 and 86 RM provide potential for more cover crop biomass than later-season hybrids but recognize there may be a negative impact on corn yield. Under irrigation, early planting is important for late-season hybrids to achieve maximum yield potential. Under rain-fed, late planting affected negatively yield for all hybrids compared with early planting. 10

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