- Animals: bovine, sheep
- Animal Production: grazing - continuous, grazing management, grazing - rotational, stocking rate
- Crop Production: irrigation
- Education and Training: farmer to farmer, on-farm/ranch research, participatory research
- Natural Resources/Environment: carbon sequestration
- Soil Management: soil microbiology, soil chemistry, organic matter, soil quality/health
Despite extensive attention to mob grazing and its purported benefits, this study failed to find any significant difference between mob-grazed and Management Intensive Grazed (MiG) plots at any of the locations for any of the soil or forage parameters measured.
In recent years, mob grazing has gained increased attention as a management practice due to the purported benefits of improved forage yield, greater soil water retention, increased soil carbon sequestration, and range and pasture renovation. The practice involves using high stocking rates of animal pounds per acre which are moved frequently to new paddocks. The large amount of disturbance and extended rest periods that defines this practice is hypothesized to affect soil physical properties, soil biological activity, forage growth cycles and pasture species composition. Unfortunately, little quantitative research had been pursued to validate these claims when this project was proposed, although some research has been completed or started in the last few years.
Small-scale farmers in Southern Oregon have expressed increasing interest in adopting mob grazing practices. If the benefits of this practice are substantiated, then mob grazing could help to stabilize farm risk by increasing pasture resilience to extremes in rainfall and temperature and by increasing forage yields. In this way, the practice could enhance small-scale Southern Oregon farmers’ economic viability and quality of life by reducing inputs, increasing the length of the grazing season and buffering pasture systems from extreme weather events and climate change impacts.
This project worked with five producers in Jackson County to quantify the effects of mob grazing on soil organic carbon, soil water, soil biological activity, pasture yield and pasture species composition. This project was also used as a tool to educate Jackson County producers about the practice and its adaptability and benefit to local agro-ecosystems.
In Southern Oregon, innovative farmers are highly engaged in developing new systems approaches to enhancing whole farm sustainability. This project proposes to work with producers to define mob grazing and quantify the effects of such practices on overall pasture productivity. As claims of increased pasture productivity from mob grazing are attributed to improved soil health, this study will measure below-ground and above-ground parameters to test the hypothesis that mob grazing results in increased forage yields, forage species diversity and improved soil health parameters such as available water, soil organic carbon and soil biological abundance. The specific achievable objectives of this project include the following:
1. Define mob grazing based on an upper and lower limit of animal pounds per acre and a minimum recovery period to standardize regional discussions among producers and treatments implemented during this study (April 2013 ).
2. Implement grazing treatments at three locations across Southern Oregon. Two of the locations are paired farms (four total producers), with one of each pair housing management intensive grazing and mob grazing treatments, and the neighboring farm providing the control (either continuous grazing or set-stocking). The fifth farm (third location) will have management intensive grazing, mob grazing and no grazing treatments.(May 2013).
3. Collect site specific information at each of the three farms, including past management history, climate, aspect, slope, soil texture, soil pH, soil type, bulk density and baseline data for measured treatment parameters (May 2013).
4. Collect soil and forage data for three consecutive years (May 2013-October 2015). The measured parameters will include the following:
a. Total annual forage production, as measured prior to each treatment event or at the end of the season for the control treatment.
b. Pasture species richness and abundance, including weed species, measured annually in mid-summer.
c. Total soil organic carbon and nitrogen, measured annually at the end of the grazing season.
d. Annual soil biological assessment, including active and total bacteria and fungi, protozoa and nematodes.
e. Additional soil parameters – pH, bulk density and infiltration rates, measured annually at the end of the grazing season.
f. Soil moisture content, monitored throughout the growing season.
5. Statistically analyze results to determine treatment effects on forage production, forage species diversity and soil parameters, annually and over the three-year experiment (December 2015).
6. Provide site tours pre- and post- mob grazing treatment events to familiarize producers with how pastures look under this management. Combine site tours with training in use of soil quality scorecards and pasture assessment tools (July 2013, July 2015).
7. Present study results to producers regionally. Survey producers for interest in adoption of mob grazing practices (October 2013, October 2014, October 2015).
8. Develop a fact sheet summarizing the results of this study (December 2015).