Influence of Timing and Degree of Weed Management on Crop Yield and - - PowerPoint PPT Presentation

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Influence of Timing and Degree of Weed Management on Crop Yield and - - PowerPoint PPT Presentation

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Influence of Timing and Degree of Weed Management on Crop Yield and Contribution to Weed Emergence the Following Year Introduction Timing of weed control generally influences yield (Everman et al. 2008; Knezevic et al. 2003; Tursun et al. 2016)

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Influence of Timing and Degree of Weed Management on Crop Yield and Contribution to Weed Emergence the Following Year

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Introduction

  • Timing of weed control generally influences yield (Everman et al.

2008; Knezevic et al. 2003; Tursun et al. 2016)

  • Weed management costs for agronomic crops can vary considerably

(Jordan et al. 2014)

  • Most weed management trials focus only on a single crop without

documenting impacts on subsequent seasons

  • Few experiments include multiple crops in a manner allowing direct

statistical comparisons

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Objectives

  • To determine the number and timing of herbicide applications needed

to optimize weed control, yield, and estimated economic returns in corn, cotton, grain sorghum, and soybean

  • To compare the effect of crop or herbicide program during the

previous year on contributions to the seedbank

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Materials and Methods

  • Locations: Lewiston-Woodville (Norfolk sandy loam) and Rocky

Mount (Aycock very fine sandy loam)

฀ Common ragweed and Texas millet (Lewiston-Woodville) ฀ Palmer amaranth and large crabgrass (Rocky Mount)

  • Year 1

฀ Corn, cotton, grain sorghum, and soybean planted early May ฀Experimental design: split-plot with summer crop serving as the whole plot unit and timing of herbicide application serving as the sub-plot unit ฀ Plot size: 4 rows (91-cm spacing) by 9 m ฀Management other than weed control of all crops was based on North Carolina Extension Service recommendations

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Materials and Methods

  • Herbicide application timings

฀ 2 weeks after planting (WAP) only ฀ 6 WAP only ฀ 2 and 4 WAP ฀ 4 and 6 WAP ฀ 2, 4, and 6 WAP ฀ Non-treated control

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Herbicides

Lewiston-Woodville WAP 2 4 6 Corn glyphosate glyphosate glyphosate Cotton glyphosate glyphosate glyphosate Grain sorghum quinclorac bentazon bentazon Soybean glyphosate glyphosate glyphosate Rocky Mount WAP 2 4 6 Corn glyphosate + dicamba glyphosate glyphosate Cotton glyphosate + dicamba glyphosate + dicamba glyphosate Grain sorghum quinclorac bentazon bentazon Soybean glyphosate + dicamba glyphosate + dicamba glyphosate

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Materials and Methods

  • Application Equipment:

฀ CO2- pressurized backpack sprayer calibrated to deliver 140 L / ha at 125 kPa

  • Data collection

฀ Visual ratings of percent broadleaf and annual grass control 7, 10, and 20 WAP ฀ Yield (converted to percent of maximum) ฀ Estimated Economic Returns

  • Weed control, percent maximum yield, and estimated economic

returns were subjected to ANOVA using PROC GLIMMIX and means were separated using Fisher’s Protected LSD at p < 0.05

  • Factorial arrangement of 4 (Crop) × 6 (Herbicide Application Timing)
  • Pearson Correlation Coefficients were constructed
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Materials and Methods

Crop Average Price Base Cost $ / kg $ / ha Corn 0.21 ($5.33/bu) 805 ($326/ac) Cotton lint 1.60 ($0.72/lb) 1,224 ($496/ac) Cottonseed 0.20 ($0.09/lb)

  • Grain sorghum

0.17 ($3.86/bu) 613 ($248/ac) Soybean 0.42 ($11.43/bu) 589 ($239/ac)

*Prices are from 10 year USDA-NASS data (2008-2017)

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Materials and Methods

  • Year 2

฀ Cotton planted into previous season’s plots ฀ Herbicide program included POST applications of glyphosate and/or glyphosate plus dicamba at 3 and 7 WAP

  • Data collection

฀ Weed population densities recorded 3, 7, and 20 WAP ฀ Cotton lint yield

  • Data for weed population densities and cotton lint yield were subjected

to ANOVA using PROC GLIMMIX and separated using Fisher’s Protected LSD at p < 0.05

  • The factorial arrangement of treatments during the previous year was

considered

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Lewiston-Woodville Year 1

2016 Common ragweed: 129 plants / m2 Texas millet: 75 plants / m2 2017 Common ragweed: 29 plants / m2 Texas millet: 16 plants / m2

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Analysis of variance (P > F) for common ragweed and Texas millet control 10 WAP, percent maximum yield, and estimated economic returns at Lewiston-Woodville. Source of variation Common ragweed control (10 WAP) Texas millet control (10 WAP) Percent maximum yield (%) Estimated economic returns ($ / ha) Year 13.3* 4.0* 0.4 39.3* Crop 9.5* 16.0* 36.2* 347.8* Herbicide Application Timing 328.0* 25.4* 169.2* 135.5* Year × Crop 4.6* 9.5* 3.1* 37.0* Year × HAT 13.7* 1.5 6.9* 11.4* Crop × HAT 22.3* 8.9* 28.4* 30.5* Year × Crop × HAT 3.1* 1.2 2.1* 2.3* * indicates significance at p < 0.05.

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Rocky Mount Year 1

2016 Palmer amaranth: 54 plants / m2 Large crabgrass: 51 plants / m2 2017 Palmer amaranth: 65 plants / m2 Large crabgrass: 89 plants / m2

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Analysis of variance (P > F) for Palmer amaranth and large crabgrass control 10 WAP, percent maximum yield, and estimated economic returns at Rocky Mount. Source of variation Palmer amaranth control (10 WAP) Large crabgrass control (10 WAP) Percent maximum yield (%) Estimated economic returns ($ / ha) Year 3.1 72.0* 3.5 24.3* Crop 11.1* 9.3* 19.6* 102.9* Herbicide Application Timing (HAT) 96.9* 10.9* 59.1* 35.2* Year × Crop 20.0* 3.2* 1.2 8.3* Year × HAT 9.1* 2.4* 2.4* 1.0 Crop × HAT 3.9* 2.3* 9.4* 12.5* Year × Crop × HAT 3.7* 2.0* 1.2 2.5* * indicates significance at p < 0.05.

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Subsequent Season Cotton Year 2

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Analysis of variance (P > F) for broadleaf and grass densities 3 WAP and cotton lint yield.

Source of variation Broadleaf densities (3 WAP) Grass densities (3 WAP) Cotton lint yield Experiment (Exp) 86.6* 24.6* 798* Crop 22.7* 9.8* 4.7* Herbicide application timing (HAT) 9.1* 4.2* 0.4 Exp × Crop 9.3* 2.8* 6.0* Exp × HAT 0.9* 0.8 1.5 Crop × HAT 1.0 2.1* 1.0 Exp × Crop × HAT 1.1 0.7 1.1

* indicates significance at p < 0.05.

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Summary

  • Common ragweed control in corn and soybean was optimum when

herbicides were applied at any time while cotton required two applications or a single application at 6 WAP

  • A single herbicide application late generally was not as effective at

controlling Palmer amaranth as it was controlling common ragweed

  • In grain sorghum, greater control was noted when a 2 WAP

application was included in the herbicide program

  • When herbicides were not applied, maximum yield of corn was

greatest of the four crops

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Summary

  • Estimated economic returns were greater for corn followed by soybean

followed by cotton at Lewiston-Woodville in most cases when comparing timing of herbicide applications

  • Estimated economic returns often were similar for corn and soybean at

Rocky Mount when comparing herbicide applications

  • Common ragweed populations were lower following corn
  • In one year, Palmer amaranth populations were greater following grain

sorghum

  • Late season weed control ratings often reflected interactions of weed control

and competition of the weed complex

  • Differences in herbicide efficacy across crops
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Impact of Weed Management on Peanut Yield and Weed Populations the Following Year

*Initially a component of Chapter 2 Annual grasses were controlled across the entire experiment to facilitate digging pods and inverting vines

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Overall Summary

  • Crop response to planting date was variable and reveals challenges
  • There is potential for non-traditional double cropping systems in North

Carolina under certain circumstances

  • Generally, yields and economic returns were greater with the more

intensive weed management programs

  • Occasionally, weed management or crop in the previous season can

have effects on weed populations the following season

  • Contributions of weed seed to the soil seedbank may not be observed

in a single season

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Citations

  • Beatty, K.D. and I.L. Eldridge. 1980. 1979 results from crop rotation study, Keiser. Arkansas Farm Res. 29:6.
  • Caviness, C.E. and J.D. Thomas. 1979. Influence of planting date on three soybean varieties. Arkansas Farm Res. 28:8.
  • Everman, W.J., S.B. Clewis, W.E. Thomas, I.C. Burke, and J.C. Wilcut. 2008. Critical period of weed interference in peanut. Weed Technol. 22:63-67.
  • Foote, W., K. Edmisten, J. Bacheler, R. Nuti, R. Wells, D. Jordan, and L. Fisher. 2014. Thrips and cotton response to relay intercropping with wheat in

North Carolina. J. Cotton Sci. 18:94-107.

  • Jordan, D.L., J.S. Barnes, T. Corbett, C.R. Bogle, P.D. Johnson, B.B. Shew, S.R. Koenning, W. Ye, and R.L. Brandenburg. 2008. Crop response to

rotation and tillage in peanut-based cropping systems. Agron. J. 100:1580-1586.

  • Jordan, D.L., D.E. Partridge, J.S. Barnes, C.R. Bogle, C.A. Hurt, R.L. Brandenburg, S.G. Bullen, and P.D. Johnson. 2004b. Peanut response to tillage

and rotation in North Carolina., p 215-219, In D. L. Jordan and D. F. Caldwell, eds. Proc. Southern Conserv. Tillage Conf. for Sustainable Agric., 26th, Raleigh, North Carolina 8-9 June 2004. Tech. Bull. No. TB-321. North Carolina Agric. Res. Serv., Raleigh, NC.

  • Lewis, W.M. and J.A. Phillips. 1976. Double cropping in the eastern United States. In Journal series of the North Carolina State Univ. Agric. Ext. Ser.,

Raleigh.

  • Mahoney, D.J., D.L. Jordan, R.L. Brandenburg, B.R. Royals, M.D. Inman, A.T. Hare, and B.B. Shew. 2018. Peanut Sci. 45:70-74.
  • Moss, J.W., R.S. Tubbs, T.L. Grey, N.B. Smith, J.W. Johnson, J.W. Davis. 2012. Agronomic and economic comparisons of double-crop and relay-

intercropping systems of peanut with wheat. Crop Manage. Available online. Doi:10.1094/CM-2012-0925-03-RS.

  • Smith, C.W. and J.J. Varvil. 1982. Double cropping cotton and wheat. Agron. J. 74:862-865.
  • USDA-NASS. 2018. Quick Stats [online]. Available at https://quickstats.nass.usda.gov (accessed 21 Aug. 2018).
  • Washburn, D. 2019. Enterprise budgets. Available at https://cals.ncsu.edu/are-extension/business-planning-and-operations/enterprise-budgets/
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Acknowledgments

  • Committee: Drs. David Jordan, Keith Edmisten, Angela Post, and

Ramon Leon

  • Derek Washburn
  • Rick Seagroves, Shep Lassiter, and Scott Whitley
  • Matt Inman, DJ Mahoney, and other fellow graduate students
  • Staff at PBRS and UCPRS
  • Funding: North Carolina Peanut Growers Association Inc.
  • Departmental resources and funding
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Questions