Grass-Legume pastures to increase economic and environmental sustainability of livestock production

Project Overview

SW10-088
Project Type: Research and Education
Funds awarded in 2010: $209,907.00
Projected End Date: 12/31/2014
Grant Recipient: USDA-ARS
Region: Western
State: Utah
Principal Investigator:

Annual Reports

Commodities

  • Agronomic: grass (misc. perennial), hay, general hay and forage crops
  • Animals: bovine

Practices

  • Animal Production: feed/forage, grazing management, grazing - rotational, pasture fertility
  • Crop Production: irrigation, nutrient cycling, organic fertilizers
  • Education and Training: demonstration, extension, farmer to farmer, on-farm/ranch research, workshop
  • Farm Business Management: budgets/cost and returns
  • Soil Management: nutrient mineralization

    Proposal abstract:

    Recent high costs of nitrogen fertilizer and the need for increased environmental stewardship necessitates a renewal of the mixed grass-legume pasture. Past research was not indicative of the irrigated, rotational grazing systems common to the western U.S. There are few guidelines on which species and grass-legume ratios optimize economic and environmental sustainability. This experiment proposes to (1) compare livestock performance, economics, and subsequent meat quality of beef produced from grass monocultures versus low- and high-tannin grass-legume mixtures, (2) determine best possible grass-legume mixtures and plant densities that maximize pasture productivity, and (3) determine if high-tannin legumes can reduce potential nitrogen-based environmental impacts in grass grazing systems. Overall this research will evaluate the economic and environmental benefits of grass-legume pasture mixtures as compared to using commercial nitrogen fertilizer.

    Project objectives from proposal:

    Three objectives and accompanying performance targets are listed below. Performance targets are made under the assumption that Year 1 runs from May 2010 to April 2011; Year 2 from May 2011 to April 2012; and Year 3 from May 2012 to April 2013. Year 4 would run from May 2013 to April 2014 and is beyond the scope of funding, but would be required in some instances to complete data analyses and prepare manuscripts.
    Objective 1. Compare livestock performance, economics, and subsequent carcass characteristics from beef grazing grass monocultures and low- and high-tannin grass-legume mixtures versus traditional feedlot-based finishing.
    Year 1: Begin grazing (plots established in 2009); measure feed intake, body weight, dry matter and nutrient digestibility (crude protein and fiber); and determine feed efficiency, and plasma urea nitrogen during growing and finishing periods.
    Year 2: Collect second year data on feed intake, body weight, and dry matter and nutrient digestibility; determine feed efficiency, and plasma urea nitrogen during growing and finishing period; and develop fact sheets for use at pasture walks and field days.
    Year 3: Conduct continuous culture study using feed samples collected from growing and finishing periods to investigate ruminal fermentation characteristics (ammonia-N, VFA, methane, microbial protein synthesis, and digestibility); evaluate meat quality of steers slaughtered after the finishing period in year 1 and 2 (FA analysis, tenderness, sensory panel evaluation, and lipid and color stability measurements); and revise fact sheets for symposium.
    Year 4: Complete data analysis; and prepare journal manuscript(s).

    Objective 2. Determine best possible grass-legume mixtures and plant densities that maximize pasture productivity and nutritional quality.
    Year 1: Plot establishment (seed plots and measure frequency of establishment).
    Year 2: Begin grazing and collect first year of plot yield, nutritional quality, and stand frequency; develop NIRS equation that separates species composition; and develop fact sheets for use at pasture walks and field days.
    Year 3: Collect second year of plot yield, nutritional quality, and stand frequency; and begin data analysis.
    Year 4: Complete data analysis; revise fact sheet(s) and prepare journal manuscript.

    Objective 3. Determine the effects of tannins on nutrient cycling in grazing systems.
    Year 1: Pasture establishment; and collect baseline soil and leachate data.
    Year 2: Begin grazing and collect first year of soil, plant, and leachate data; sample analyses; and develop fact sheets for use at pasture walks and field days.
    Year 3: Second year of collection of soil, plant, and leachate data; sample analyses; and begin data analysis.
    Year 4: Complete data analysis; revise fact sheet(s) and prepare journal manuscript.

    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.