Shade Effects on Yield, Botanical Composition, Nutritive Value, and Ergot Alkaloid Concentrations of Forage Mixtures for Silvopastures

Project Overview

Project Type: Graduate Student
Funds awarded in 2016: $11,000.00
Projected End Date: 08/31/2017
Grant Recipient: Virginia Polytechnic Institute and State University
Region: Southern
State: Virginia
Graduate Student:
Major Professor:
Dr. Chris Teutsch
Virginia Polytechnic Institute and State University


  • Agronomic: clovers, grass (misc. perennial), medics/alfalfa
  • Animals: bovine


  • Animal Production: feed/forage
  • Crop Production: agroforestry, shade cloth, silvopasture
  • Natural Resources/Environment: biodiversity
  • Pest Management: competition


    Silvopastures integrate trees, forages, and livestock.  Tall fescue, the dominant forage in much of the U.S., harbors an endophyte that produces toxic ergot alkaloids.  Diluting the sward with other forages can reduce ergot alkaloid concentrations, but it is unknown how shade impacts alkaloid production and productivity of different forage mixtures. This study tested the effects of increasing shade and mixture complexity on sward yield, botanical composition, nutritive characteristics and ergot alkaloid concentrations.  Slatted shade structures created 30, 50, and 70% shade compared to full sun.  Three forage mixtures were evaluated (SIMPLE = tall fescue and white clover; INTERMEDIATE = SIMPLE + orchardgrass and red clover; and COMPLEX = INTERMEDIATE + Kentucky bluegrass, birdsfoot trefoil, and alfalfa). 

    Fifty and 70% shade reduced yield while red clover and orchardgrass dominated shaded swards.  Birdsfoot trefoil, Kentucky bluegrass, and white clover did not perform well in any treatment.  Nutritive value declined beneath shade in spring and fall.  Sward ergot alkaloid concentration increased beneath shade in simple mixtures because of greater proportions of tall fescue.  In the intermediate and complex mixtures, ergot alkaloids were diluted by other forage species and was not affected by shade.  This illustrates the importance of incorporating multiple species into the sward.  Low light levels may not have been sufficient to meet the forages’ high energetic demands in the spring.  Even though total forage production or nutritive value may be sacrificed during part of the year, this may be compensated for by diverse swards diluting ergot alkaloid concentrations.

    Project objectives:

    1. To compare the response of forage species mixtures to different shade levels. Measures of interest include: a. Biomass production b. Species composition c. Nutritive value (protein and fiber concentrations), and d. Ergot alkaloid concentrations
    2. To present data on our findings to researchers, technical service providers, and producers interested in forage-livestock system management in the fescue belt
    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.