Project Profile: Herbicide and Cover Crop Interactions

About Daniel Smith

Dan_Smith_300px
I have always had a strong passion for crop production. I was first introduced to agriculture on my grandparents’ corn and soybean production farm. As I entered high school I became heavily involved in FFA and 4-H eventually earning my American FFA degree. This interest in agriculture led me to obtain bachelor’s degree majoring in Soil and Crop Science and Agriculture Business from the University of Wisconsin-Platteville. I interned with several private agronomy companies focusing on crop protection and production and operated my own part-time landscape contracting business. Currently, I am pursuing a Master’s degree in Agronomy at UW-Madison.

Contact Information:
dhsmith@wisc.edu


Herbicide and Cover Crop Interactions in Corn, Soybean, and Wheat Cropping Systems

Background

Cover crops are a growing interest for corn and soybean producers in the Midwest region due to the benefits of reducing soil erosion, providing and scavenging nutrients, and increasing soil organic matter. Herbicide applications common to Wisconsin cropping systems can have adverse effects on the establishment of cover crops through herbicide carryover. Cover crops can also become weeds if not properly terminated.


Objectives

  1. To determine whether common soil applied herbicides with residual weed control properties applied during the establishment of corn, soybean, and wheat crops affect the subsequent establishment of cover crops in the fall.
  2. To determine the best spring termination method for over-wintering cover crops grown in Wisconsin.

Approach

Objective 1:

  • Field experiments will be conducted using a randomized complete block design with four replications. Corn, soybean, and wheat crops will be the whole plot factor crop and the sub-plot factor will be herbicide treatments and sub-sub-plot factor will be cover crop species. Each crop will include a control treatment with no residual herbicide applied
  • Corn and soybean crops will be harvested for forage. Wheat will be harvested for grain and straw.
  • Seven different cover crop species and/or varieties will be tested. These will include tillage radish (Raphanus spp.), crimson clover (Trifolium incarnatum), cereal ryegrass (Secale cereale), 70% oat (Avena sativa) plus 30% peas (Pisum sativum) mixture, and three annual ryegrass (Lolium multiflorum) varieties. The annual ryegrass varieties included diploids ‘Bruiser’ and ‘King’, and a tetraploid.
  • Cover crops will be evaluated roughly two months after establishment for herbicide injury. The evaluation methods include visual ratings for stand reduction and injury, normalized difference vegetative index readings (NDVI) for greenness and percent cover, digital image analysis for percent cover, stand counts, and biomass collection.

Objective 2:

  • A field experiment will be conducted to determine the best methods to terminate winter rye (S. cereale) and several annual ryegrass (L. multiflorum) varieties. The experiment will be conducted using a split plot design with cover crops being the main plot factor and herbicide treatments being the sub-plot factor. Each crop will include a control treatment with no termination treatment to evaluate efficacy of treatment.
  • Termination methods will be implemented early in the spring allowing enough time for full termination before the main crop will be planted.
  • Cover crops will be evaluated in the fall two months after establishment and two weeks prior to field crop planting in the spring. The measurements will include visual ratings for stand reduction and injury, NDVI readings for greenness and percent cover, digital image analysis for percent cover, stand counts, and biomass collection.

Presentations

  • 2014 North Central Weed Science Society poster, “Termination strategies for winter rye and overwintering annual ryegrass with glyphosate” [PDF]
  • 2014 North Central Weed Science Society paper, “Herbicide carryover evaluation in cover crops following corn silage and soybean herbicides” [PDF]
  • 2013 North Central Weed Science Society poster, “Herbicide carryover evaluation in cover crops following corn and soybean herbicides” [PDF]

Extension Presentations

  • 2015 Wisconsin Association of Professional Agricultural Consultants, “Cover crop termination methods and challenges,” [PDF]
  • 2015 Wisconsin Crop Management Conference, “Cover crop establishment following commonly applied corn and soybean herbicides in Wisconsin” [PDF]
Updated March 3, 2015