Project Overview
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
Abstract:
High costs of nitrogen fertilizer and increased environmental stewardship necessitates a renewed interest in mixed grass-legume pastures, and past grass-legume research is not indicative of the irrigated, rotational grazing systems in the western U.S. This research compared the forage production, livestock performance, and economics of grazing pastures of tall fescue-alfalfa, tall fescue-birdsfoot trefoil, and tall fescue monoculture with and without nitrogen fertilizer. This Sustainable Agricultural Project Team showed that a pasture mixture of tall fescue and the condensed-tannin-containing legume, birdsfoot trefoil, improved nitrogen utilization and steer weights, as compared to using commercial fertilizer on tall fescue. They also demonstrated, via in-vitro studies, that grass-legume mixtures with and without supplemental nutritive energy improved ruminal nitrogen utilization resulting in less ammonia and methane production. While yearly forage yields of grass-legume mixtures were slightly lower than fertilized tall fescue, small-plot studies determined that certain grass-legume mixtures and ratios were more productive than fertilized grass monocultures. Analyses of leachate samples indicated that grass-legume mixtures result in lower nitrate concentrations in leachate, compared to N fertilizer; and, thus, reduce groundwater contamination. Finally, the tall fescue-legume mixtures doubled the economic return when compared to fertilized tall fescue monocultures. Multiple on-farm tours (at the participating producer’s farms), research station field days, and forage schools demonstrated these findings to approximately 600 participants. Results were also presented at national and international professional meetings and published in five peer-reviewed articles or proceedings, garnering attention from all over the world. Overall, these results suggest that grass-legume mixtures can improve livestock and pasture productivity and economic and environmental sustainability.
Project objectives:
Three objectives and accompanying performance targets are listed below.
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; 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: 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.