EXT 17 Assessing and demonstrating effects of a simple rotational grazing system on forage production and soil fertility
At this First Street Pasture, MBFI together with Agriculture and Agri-Food Canada is researching techniques for improving soil health and forage productivity through rotational grazing on infertile pastures. This page will provide information about this particular research project; including the background, objectives, and updates.will
- Project Lead: Mae Elsinger, Agriculture and Agri-Food Canada
- Project Start: June 2015
- Project Status: Completed October 2017
- Location: First Street Pasture
About This Project
The First Street Pasture is a poorly productive pasture, dominated by smooth brome (Bromus inermis Leyss.) and Kentucky bluegrass (Poa pratensis L.). Leafy spurge (Euphorbia esula L.) is also encountered throughout. The majority of the pasture is of sandy surface texture or Clay Loam overlying sand and gravel and seems to have low fertility and organic matter. No historical grazing records or forage production data were kept by the previous users of First Street Pasture. Critical components for grazing records include type and class of livestock, and herd entry and exit dates to and from each field. This data allows a person to calculate a standardized level of forage utilization, and to develop an expectation for next year’s grazing capacity (by considering long term annual grazing report data plus weather information).
Lots of pastures like First Street appear in Manitoba (e.g. Crown lands and well-aged pastures), and for various reasons their landowners are reluctant to put full effort into rejuvenating them (ie. restricted on Crown lands and uneconomical on others). Even a simple rotational grazing system, like the one implemented at First Street Pasture, is expected to improve pasture and soil health with improved livestock distribution throughtout the landscape, stimulation of the leaf and root growth of forage through grazing and trampling, and providing an effective rest or recovery period for grazed forages.
To implement the desired rotational grazing system, the First Street Pasture was subdivided into 10 fields with single-strand interior fences. A shallow buried PVC pipeline with several spigots provides water to the fields. Fifty cow-calf pairs were rotated through the fields from June to September of 2015, and fifty heifers plus a few cow-calf pairs were rotated in the same months of 2016 with additionals days in May. Soil fertility, pasture prodocutivity, pasture health, anad grazing data will be documented and studied.
- To study and document plant productivity and soil fertility changes through time, resulting from late May to October grazing rotation through ten large fields.
- To demonstrate a method for keeping grazing records to help in future grazing decisions.
- To demonstrate a Grazing Response Index method of assessing and adapting to current year’s grazing management impacts.
As of March 2017-MBFI’s First Street Pasture Historical Grazing Record is going into in its third year. From the first two years of grazing rotation data and 2 years of forage yield data we were able to show that we could graze more cattle, or extend the grazing period, or use stock with larger demand (cows versus heifers). However, we have yet to experience a drought year to see how low the minimum livestock carrying capacity will go.
Grazing Response Index was rated for each study location for both the 2015 and 2016 grazing seasons, by evaluating the direct impacts of the grazing system on key forages. All 3 fields in this study had high positive values showing that this simple rotational grazing system should benefit the forages. Opportunity to rest is providing the greatest benefit. A Tame Pasture Health Assessment rated 2 study locations Healthy, and 4 study locations Healthy with Problems. All 6 study locations are dominated by exotic grasses (Kentucky bluegrass, smooth brome, and quackgrass), but abundance of productive tame forages (smooth brome) and legumes (alfalfa) is limited. Plant litter cover (residue) was very high in the moister depressions but poor to fair in drier upland areas. The only weed of concern is leafy spurge.
Watch the projects about leafy spurge biological control, teaching cattle to eat leafy spurge, and increasing production through management to learn some low cost measures for improving this pasture
As of Septermber 2015 - During the summer of 2015 single-strand interior electric fences were installed to create 10 smaller fields. A shallow buried PVC pipeline was also installed that extended through the east and north of the pasture, with several spigots servicing the fields. Fifty cows were grazed on the pasture from June to September and were moved throughout the smaller fields during that time. There are an increasing number of producers using an intensive rotational grazing system, in comparison the First Street pasture was divided into larger paddocks and the cattle spent more time in them. This rotational management system would lie between the more intensive systems and a continuous grazing system. Baseline measurements of soil and forage biomass were taken.