Jalama Canyon Ranch 2022 Prescribed Grazing

Range-C Background

Thank you for participating in the Rangeland Carbon Monitoring Program pilot studies. Range-C was developed to help practitioners conduct transparent, fit-for-purpose monitoring of aboveground and belowground carbon in response to rangeland management. At the same time that it supports management efforts at the farm scale, The Range-C Program is designed to evaluate management effects on carbon at regional scales when data is aggregated network-wide in the secure Point Blue Science Cloud. Your contribution as a pilot ranch has advanced our ability to apply the framework to diverse settings as we develop systems for land steward onboarding, and project design as well as data collection, storage, and analysis.

Project Design

The monitoring plan developed for the 2022 Prescribed Grazing practice at Jalama Canyon Ranch results in an inference score of 73. Inference scores range from 40 to 100 and reflect how decisions made in the project design process impact the overall reliability and interpretability of the data. Projects with higher inference scores generally reflect greater confidence in the project’s findings or a more holistic characterization of carbon dynamics in the study site. Nonetheless, all Range-C projects represent a minimum standard of rigor. Refer to the graphic below for a visual representation of how different project design decisions contribute to the inference score.

A visual representation of how different project design decisions impact the final inference score

Figure 1: A visual representation of how different project design decisions impact the final inference score

Carbon indicators and sampling densities

The following table lists carbon indicators that were included in this monitoring project, defines acronyms that will be used in following tables, describes what each one measures, and defines the units that each will be reported in.

Table 1: Description of carbon indicators
Carbon Indicator Acronym Description Final units
Soil Organic Carbon SOC Carbon bound up in soil organic matter (SOM), which is composed of decomposing plants and animals, soil microbes, and the substances that soil microbes synthesize. SOC is a direct measurement of soil carbon sequestration and soil health. % mass of SOC over soil mass; when BD is also measured, % SOC will be converted to tons of SOC stored per acre to the project’s specified sampling depth
Aboveground Herbaceous Biomass AHB Mass of living grasses and forbs above the soil. AHB serves as a measure of forage productivity; turns into soil carbon over time through decomposition. Tons of dry biomass produced per acre per year

Other design elements

This Range-C project includes baseline monitoring before the conservation practice was implemented, but did not include parallel monitoring at an untreated control site. Soil samples were taken to a target maximum depth of 12 inches. Depth increments from 0-15 and 15-30 were analyzed separately. Each soil sample was composed of smaller composited samples to capture small-scale variability at each sampling point. Sampling points were randomly selected within the monitoring boundary using mapping software and located in the field by GPS.

Spatial Design

A map of the study area showing where samples were taken

Figure 2: A map of the study area showing where samples were taken

The following indicators were measured at every sampling point: Soil Organic Carbon

Indicators that were only measured at some sampling points are listed in the table below.

Table 2: Indicators measured at a subset of sampling points
Indicator Treatment points
AHB 03, 06, 10, 14, 16, 19, 22, 23, 26, 27, 33

Results

The following table summarizes the soil metric(s) included in your project design. These values do not represent carbon stocks, but provide valuable context for interpreting carbon dynamics at the study site.
Table 3: Soil Metrics
Indicator
Treatment
Name Units 0-15 15-30
SOC % 2.63 1.93


The following bar chart(s) show carbon stocks stored in the study area for indicators included in your project design.
Keep in mind that since this project did not include bulk density measurements, soil organic carbon will only be reported as a percentage in the above table and not in the stocks figures below.

The previous tables and figures reported results averaged across the study area. Use the interactive map below to explore results at each sampling point. Hover over the layers symbol to select from included metrics.

FAQ

How can I interpret 1 ton of carbon per acre?

One ton of carbon per acre is equal to 3.67 tons of CO2 removed from the atmosphere, equivalent to 1 year of passenger car emissions. It is important to note that 1 ton of carbon per acre in our soil data is only to a 12 inch depth; much more carbon can be stored below that depth. Soil and woody biomass carbon are considered a longer-term form of storage than forage biomass.

How is biomass measured?

We measure woody tree biomass using equations that convert a tree’s height and diameter into biomass. We measured aboveground forage biomass by excluding grazing animals from a representative location in the study area and clipping a sample of plants once peak forage biomass is reached for the season. We then dried and weighed these samples in the lab.

Why is monitoring soil organic carbon important?

Soil organic carbon makes up the majority of soil organic matter which provides a variety of services in rangeland ecosystems. Soil organic carbon benefits soil organisms by creating a structured, porous environment. In turn, these soil organisms then increase fertility by cycling nutrients from waste materials, leading to higher productivity. Soils with higher levels of organic carbon have higher water holding capacity contributing to overall landscape resilience. Understanding how soil organic carbon changes in response to management practices across a variety of soils and climates, will help us prioritize lands for maximum conservation planting impact.

As a land steward, how do I use all of this information?

As with most monitoring data, comparing across different areas of your own ranch is most useful. You can gauge how different sites across the study area differ in key metrics. Additionally, the information in this report provides a baseline to measure the impact of future management changes.

Conclusion

Thank you for your participation in the Rangeland Carbon Monitoring program as a pilot study participant. If you are interested in our methods to continue monitoring, you are welcome to explore the collaboratively created Range-C Handbook. We’re also happy to announce the recent launch of the Cropland Carbon Monitoring Program and its Handbook of Field Methods. For more information on both programs and to explore the handbooks, visit the Ag-C landing page.

For more information on project design, further interpretation of results, or to access the raw data from your study site, please reach out to RangeC@pointblue.org. Our team is happy to engage with additional questions or feedback.