The Critical Role of Soil Microbiota to Sustainable Agriculture: Quantifying short-term microbial and vegetation feedback to intensive grazing.

View the project final report

Commodities

• Agronomic: grass (misc. annual)
• Animals: bovine

Practices

• Animal Production: grazing management, grazing - continuous, grazing - rotational, pasture fertility, rangeland/pasture management, stocking rate
• Soil Management: soil analysis, soil microbiology, soil quality/health

Sustainable pasture management is critical to agricultural production, but the potential benefits of high intensity grazing on soil health are still largely unquantified. It is not known how soil microbial communities respond to high-intensity, short-duration grazing, and how quickly soil microbial and vegetation communities respond. This will be addressed in the proposed research by evaluating the response of soil physical, chemical, and biological parameters to intensive grazing over a growing season, and contrast those to conventional, low-intensity grazing and grazing exclusions. These responses will be measured both immediately following intensive grazing, and over a full growing season. In addition, a novel methodology will be tested for monitoring vegetation growth on short time scales, using ground-level spectral images. There is a lack of scientifically sound data on the effects of intensively managed grazing, so this study will evaluate the consequences of changing grazing management regimes, and will contribute new knowledge about the impact of intensive grazing on soil biology and soil health, in addition to using new technology to link above-and below-ground ecosystem processes in a novel and creative way. The results and management recommendations will be disseminated to producers via Extension outreach and to undergraduate students at University of Wyoming as part of soil health curriculum. To convey results to the scientific community, we will submit manuscripts to peer-reviewed journals and present the research findings at the Society of Range Management Conference.

Research Questions:

1. Do soil microbial dynamics differ in response to intensive grazing regimes as opposed to light grazing and grazing exclusions?
2. Is there an immediate response of the soil microbial community to high-intensity or low-intensity grazing compared to grazing exclusions?
3. What is the effect of intensive defoliation on vegetation recovery growth?
4. Will an increase in microbial dynamics affect vegetation recovery growth?

1. Quantify the effects of high-intensity grazing compared to conventional grazing on soil physical, chemical, and biological parameters over a growing season.
2. Detect the flux of microbial community dynamics immediately following high-intensity grazing events, contrasted to fluxes that occur during conventional, low-intensity grazing.
3. Document the immediate response of vegetation to homogenous, intensive defoliation and to heterogeneous, moderate defoliation.
4. Synthesize the interactions of above-and below ground processes in response to high-intensity, short-duration grazing.