Maximizing Pasture's Grazing Potential by Sod-Seeding Alfalfa Mixtures

Background

Challenges like increased cost of feed and land requires Canadian farmers and ranchers to produce more outputs from the same amount, if not less, land. This is of particular interest to beef cattle grazing systems as pasture production notoriously requires a hefty land-base to support these large ruminants, especially on marginal and other less productive lands. Pasture rejuvenation is a strategy to improve the available forage, or the nutritive qualities of a pasture stand without removing the existing stand. While the concept of forage rejuvenation is well understood, 33% of Canadian producers do not practice pasture rejuvenation which serves as a strategy to improve forage stands and animal productivity. Introducing legumes like alfalfa, sainfoin, and cicer milk vetch into already established pastures has the potential to improve the quality of that pasture and even extend the grazing season. Mixed alfalfa/sainfoin pastures are shown to produce more biomass in the same amount of area which allows more animals to graze the same amount of land, improving pasture efficiency. This study will use field scale-testing to evaluate the potential to improve forage yields, quality, soil health and grazing potential by sod-seeding novel legume mixtures to older pasture stands in need of rejuvenation.

Objectives

• Determine establishment success of 3 sod-seeded alfalfa mix treatments
• Determine the biomass and quality of sod-seed treatments over multi-year period at 3 field sites
• Assess the effects of sod-seed legumes on soil C and N storage and cycling and soil nutrient supply power
• Evaluate grazing animal performance when grazing mixed legume pastures.
• Economic analysis of using new legume populations for pasture rejuvenation

What they will do

Field studies will be conducted at three sites covering two different soil zones in Saskatchewan and Alberta. Each site will consist of approximately 45 acres broken down into nine five-acre paddocks using permanent wire fencing. The three sod-seeded treatments will be compared to a non-seeded control. These will be spring seeded at recommended provincial rates after using glyphosate or heavy grazing as sod-suppression.

Sod-seeded treatments include:

• Yellow flower (falcata type) alfalfa (known to persist under drought/continuous grazing)
• AC Grazeland alfalfa and Glenview sainfoin
• AC Grazeland alfalfa and Veldt cicer milkvetch

Sod-seeding will occur in year 1, and spring of year 2 will mark the beginning of the grazing trial. Yearling steers will commence grazing once the available forage is 20cm high (at the 4-5 leaf stage) and remain on the paddock until forage is grazed to a uniform 8cm at which time they will be moved to the next paddock. Grazing management will remain the same for the following year.

The productivity of the pasture will be compared by evaluating soil characteristics, legume establishment, forage biomass and quality, grazing capacity and the costs and returns associated with each treatment.

Implications

Having cost-effective methods to rejuvenate tired old pastures is essential for beef and forage producers to continue to be competitive. With already tight margins, it isn’t feasible or practical to expect methods with high input cost or only minor pasture improvement to be widely adopted. Sod-seeding could be a potential low-input cost method to boost yields and productivity without busting the bank. Overall, this research aims to provide insight to producers regarding the effect sod-seeding legumes has on pasture rejuvenation in beef cattle grazing systems.