Grazing cicer milkvetch

Project Details

  • Project Lead: Kim Wolfe, Research Development Specialist, Manitoba Agriculture
  • MBFI Location(s): Brookdale Farm
  • Start Date: August 2015
  • Status: In progress

 

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 Objectives

To determine the impacts of two different grazing intensities on cicer milkvetch abundance.

 

 

Introduction

Cicer milkvetch (Astragalus cicer L.) is a cool season, perennial legume native to Eastern Europe, which has been introduced to southern Europe, North America and South America2. The inflorescence is a spike of up to 60 pale yellow to white flowers (Fig. 1) with the seedpods changing from pale yellow to black upon maturity (Fig. 2). Although difficult to establish, the plant is long-lived and competitive with vigorous creeping root system3. This species is not known to cause bloat nor does it accumulate selenium as do certain native Astragalus species. Cicer milkvetch is similar in nutritive value to alfalfa and can provide forage late into fall.

However, as mentioned cicer milkvetch is competitive and can dominate pasture systems due to its ability to outcompete grasses4. Preliminary research results  from the University of Alberta on ecological and economic impacts of cicer milkvetch in native mixed prairie grasslands indicates that the presence of cicer milkvetch increased forage quantity and quality while soil carbon and plant diversity decreased1. It is not recommended to be planted in or adjacent to natural areas or near native grasslands due to its persistent nature and ability to outcompete many grass species4.

The northwest quarter at Brookdale Farm was planted to a mixture of native grassland species 20 years ago by Ducks Unlimited. In 2004, cicer milkvetch (Astragalus cicer L.) was top-seeded in the western half of this quarter to increase productivity and the litter layer for duck habitat. However, over the past 10 years, cicer milkvetch has spread to the eastern fields in the northwest quarter and is the dominant species in the western fields. Low abundance of the planted warm season native grass species remains.

Two different rotational grazing systems have been initiated in the northwest quarter of the Brookdale Farm (MBFI project INT 1 Planned Grazing Demonstration). The first is a high density system, commonly known as “mob grazing”, and consists of a larger number of smaller paddocks, grazed with a higher number of animals per acre (5 AUMs/acre), for one day on the first pass and five days on the second pass. The second is a continuous system to which cattle have access at all times.