INT 8 Soil carbon monitoring to detect changes in soil carbon due to implementation of planned and rotational grazing; and comparison between these two systems

Project Details

  • Project Lead:Matthew Wiens, Land Management Specialist, Manitoba Agriculture
  • MBFI Location(s): Brookdale Farm
  • Collaborating Partners: Pam Iwanchysko, Farm Production Extension – Forage, Manitoba Agriculture and Marla Riekman, Land Management Specialist, Manitoba Agriculture
  • Start Date:2016
  • Status: In progress

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Objectives

To monitor for a minimum of three years, the impact on soil organic carbon of two grazing systems: Planned Grazing and Continuous Grazing.  The intention is to seek further support to continue monitoring every three years beyond the first three years to monitor longer-term changes on soil organic carbon.

 

 

 

Introduction

Most agricultural soils in Manitoba and across the globe have lost soil organic carbon since agricultural production was initiated.  Greater understanding is needed of the potential of various agricultural practices in various locations to rebuild soil organic carbon.

 

Soil scientists believe there is significant potential for agriculture to remove carbon dioxide from the atmosphere and sequester it as soil organic matter, leading to reduced rates of increase of atmospheric carbon dioxide levels while also improving the productivity of soils1. This project will attempt to provide a demonstration of the impact of certain grazing practices on soil organic carbon over time by employing the Soil Carbon Coalition approach to soil carbon monitoring2. The Soil Carbon Coalition is a nonprofit organization that works to advance the practice of turning atmospheric carbon into soil organic matter. They do this by highlighting the successes of local leadership via time-series monitoring. A number of cattle farmers in western Manitoba are adopting this approach and after three years of monitoring, some farmers are apparently observing large increases in soil carbon. 

 

Two distinct grazing systems have been established at the Manitoba Beef & Forage Initiative’s Brookdale Farm on land that had previously been either annually cropped or sporadically grazed.  The Planned Grazing system employs a documented plan at the beginning of the season to guide when and where cattle will be moved as the grazing season progresses. Cattle are moved quickly during fast growth in early spring and more slowly during slowed growth in late summer, and forage plants are observed to ensure full recovery before they are grazed a second time.  In contrast, the Continuous Grazing system allows cattle free access to the entire pasture area for the entire grazing season.

 

Note: ‘Planned Grazing’ is a term used for a grazing management approach that uses high stocking rates to rapidly impact the pasture through grazing and trampling. As such, it can be considered a type of mob grazing. However, the emphasis on planning and monitoring distinguishes “Planned Grazing” from other mob grazing methods that do not use rigorous planning and monitoring.