Final report for OW21-362
Project Information
Erosion on rangelands threatens soil health and in turn the productivity of plants, livestock, and producers. Extreme rainfall and drought are exacerbating risks of sheet erosion, and thus we must find rapid, effective ways to reduce erosion. To increase plant establishment and productivity, interest is growing in using organic amendments and native seeding with erosion control structures. We want to ask 1) does adding organic matter and/or 2) does adding propagules improve vegetation development in an actively eroding area? We propose to build rock run-downs on 9-18 headcuts on each of five dryland ranches and compare compost, mulch, and no organic amendments, with and without dryland grass seed additions. We will measure vegetation composition and biomass, soil moisture, infiltration rate, aggregate stability and other physical and chemical properties, and erosion or accretion in headcut channels. Understanding which treatment combinations yield the most rapid benefits will allow ranchers to evaluate costs and outcomes for better decision making. We will hold workshops at each ranch, three to demonstrate how to build the structures and deploy the organic amendments, and two to demonstrate how to monitor for plant and soil health after one year. We will additionally write white papers of economic analyses and peer-reviewed publications of the ecological results and present at the REGENERATE conference and Down to Earth podcast to disseminate to both producers and technical service providers working in these highly erodible lands. We will build soil health through living roots and surface cover to restore degraded working drylands.
Objective 1: Ameliorate 9-18 active headcuts on each of five ranches using erosion control structures and determine the optimal combination of organic amendment and seeding to improve plant productivity, soil health, and reduce erosion
- Submit peer-reviewed publication of results.
Objective 2: Determine the cost of each combination relative to the outcome
- Write white paper of results
Objective 3: Empower local producers to make changes in their operations to reduce erosion and improve soil health
- Conduct 5 workshops, present at the REGENERATE conference and Down to Earth podcast for regional outreach.
The timeline for the remainder of the grant (2023) is:
Spring/Summer - complete Hughes and Flowering Tree workshop
Summer - complete cost-benefit analysis (with intern)
Fall - complete pee-rreviewed publication and white paper of results
Winter - complete Down to Earth Podcast
Cooperators
- - Producer
- - Producer
- - Producer
- - Producer
- - Producer
Research
Make all erosion control structures
The ranchers marked 18-30 sites that were actively eroding. They then collected rock material onsite, or, in one case, purchased stone from a local landscaping company.
We held two workshops with expert guidance (Aaron Kaufman, Esquibel Ranch; Mori Hensley, Sol Ranch) leading groups of volunteers to learn how to build one rock dams to armor the site of active erosion to reduce further degradation (See Figure 1 in attached document from 2021). For sites without the expert guidance, we provided guidance and publications such as the erosion control field guide (https://quiviracoalition.org/erosion-control-fg/).
Baseline monitoring.
All baseline monitoring occurred in the area 4m x 4m upslope of the erosion control structure.
Infiltration Rate. Infiltration rate was collected from the center of each plot in an interspace area free of perennial vegetation. We used the single ring infiltrometer method (NRCS) and timed both the first and second inch (Figure 2 in attached document from 2021).
Aggregate Stability. We assess surface aggregate stability using standard methods and the soil stability kit (Herrick et al. 2017) for 4-6 aggregates per plot (Figure 3 in attached document from 2021). Aggregates were collected haphazardly from interspace locations throughout the plot.
Erosion/Accretion. If the channel below the erosion control structure was shallow (<50cm) and narrow (<1m) enough, we added wooden stakes to either side and used a level to ensure that they were completely level. We then used a contour measuring device (Kornecki et al. 2008) to record the cross cross sectional area of each channel with 19 points (Figure 4 in attached document from 2021).
Vegetation structure. Note- because we set up plots in December, all plants were senesced and we could not ascertain if plants were living and thus we did not take baseline point-intercept measurements. After 1y, we will collect point intercept data of ground surface cover, herbaceous layer, shrub layer, and canopy layer following standard protocols (Herrick et al. 2017).
Photos. We took photos looking upslope from the rock structure to the plot for each plot after completing treatments (See Figure 5 in attached document from 2021).
Experimental set-up
We blocked the structures by similar slope, aspect, and distance to one another within each ranch and randomly assigned treatment combinations within each block. For Sol Ranch, there was such high vegetative cover that they chose not to add additional seed; thus, they had only three replicates each of control, mulch, and compost. For all other ranches, there were three replicates each of control, mulch, and compost fully crossed with control and native seed.
Plots were measured to 4m x 4m above each erosion control structure and marked with flags and a metal tag. Plots were set up perpendicular to the slope, centered on the erosion control structure. Railroad pins were added .5m inside from the NW corner and SE corner for vegetation transect monitoring.
Compost addition: Compost for Sol, Hughes, and Tedford was purchased from Soilutions (Albuquerque, NM) and was composed of local manures, greenwaste and other select ingredients, composted for a minimum of 1 year and screened to 1/2 inch. Compost from Esquibel and Hibner was purchased from Polk’s Folly Farm, composed of pig waste, food waste, wood chips, composted for approximately 9m and unscreened. Compost was added to 0.25” thick with shovels, approximately 3 wheelbarrow fulls per plot.
Mulch addition: Mulch (“Native mulch”) for all ranches was purchased from Soilutions (Albuquerque, NM). Mulch was added to ~0.25” thick with shovels, approximately 4 wheelbarrow fulls per plot.
Native seed addition. Locally-sourced native seed was purchased from Plants of the Southwest (Santa Fe, NM) based on the composition of each site.
For Hughes (zone 8) we used Bouteloua curtipendula and Eragrostis trichodes.
For Tedford (zone 6) we used the Dryland seed mix (Bouteloua gracilis, Bouteloua curtipendula, Achnatherum hymenoides, Elymus lanceolatus, Pleuraphis jamesii, Sporobolus airoides, Festuca ovina, and Schizachyrium scoparium)
For Hibner and Esquibel (zone 4), we used Sporobolus airoides and Elymus trachycaulus.
All seeds were thoroughly mixed in a bucket and a 500mL was collected and sprinkled by hand across the entire plot.
Sol Ranch had abundant biomass and diversity on site so we did not add additional seed.
- Year 1 monitoring
All monitoring occurred in the area 4m x 4m upslope of the erosion control structure.
Infiltration Rate, Aggregate Stability, Erosion/Accretion and Photos were all collected in the same way as during baseline monitoring.
Vegetation structure. We collected point intercept data of ground surface cover, herbaceous layer, shrub layer, and canopy layer following standard protocols (Herrick et al. 2017).
Aboveground biomass. We collected all aboveground vegetation biomass in 2090 cm2 by clipping biomass to ground level.
Soil carbon. We collected a core of 0-10 cm, 4 cm diameter soil core to send for soil C (total and organic C) to Ward Labs.
References
Herrick et al. 2017. Monitoring Manual for Grassland, Shrubland, and Savanna Ecosystems. USDA-ARS Jornada Experimental Range. https://jornada.nmsu.edu/files/Core_Methods.pdf
Kornecki et al. 2008. A portable device to measure soil erosion/deposition in quarter-drains. Soil use and management 24:401-408.
We provided initial project results during the REGENERATE conference webinar week: https://youtu.be/FL_zGPZg_g4
We provide the draft Ecosphere submission as an attachment. This manuscript has been revised based on peer review and has been resubmitted, awaiting final decision. 2023 CRI ecosphere manuscript - Google Docs.
Research Outcomes
excerpted and revised from Ecosphere submission discussion section:
Although organic amendments have been shown to improve some measures of erosion resistance and soil health in global rangelands previously, it was not effective to pair organic amendments with the rock structures to enhance recovery of headcuts on arid rangelands. This was partly because the erosion control structures themselves are effective: on average across all ranches and treatments, the channels accreted 52 cm2 (SE 42 cm2) between the baseline measurements in winter of 2021 and the next measurements after one year, which is considerable given that the average channel cross sectional area was 365 cm2 (SE 6.5 cm2) in 2021. Thus, range managers interested in addressing active headcuts could prioritize physical intervention through rock structure rather than include biological intervention with seeding or organic amendments upslope of the structure.
The low magnitude of response may have been partially due to extreme drought conditions in the year of this study. While we did not have funding to support additional monitoring periods, restoration interventions in drylands can require several years of continued intervention for observable results, and are heavily dependent on rainfall (Balazs et al. 2022). However, infiltration rate and aggregate stability changed through time despite drought conditions at some ranches, suggesting that soils were capable of changing in response to climatic or operational activities even with limited precipitation to drive biological activity.
While the responses that we measured showed little response to organic amendments, anecdotally, our interns and field technicians noticed the soil moisture appeared higher due to darker color and more condensation of soil samples in plastic bags in mulch plots than control or compost within a ranch, but unfortunately, we did not collect samples for soil moisture or have volumetric soil moisture probes with us to collect that data in the field. Additionally, ranchers reported the persistence of snow for a longer time period in some of the amended locations, identifiable by the square shape of the snow above rock structures persisting as the weather warmed up. Several ranchers reported that they would be interested in trying organic amendments again to see if they would be beneficial in different contexts (for example along a fenceline where calves are weaned and the soil and plants therefore are subject to high impact) or if longer-term benefits of the erosion control interventions from this study might be obtained.
Education and Outreach
Participation Summary:
2023. All five in-field outreach events have been completed.
We completed the Indigenous-run Flowering Tree Permaculture Institute: Land Health and History Workshop; 25 participants.
We also presented on the organic amendments and erosion control workshop at the Hibner Soil Health Field Day; ~50 participants.
2022. We held one workshop in 2022 at Tedford Farm with 5 participants (out of 8 registrants) to learn to build erosion control structures, view the trials after y1, and understand how in-field monitoring can be used by producers for projects like this.
2021. Workshops were completed at Sol Ranch and Esquibel Ranch to build erosion control structures and discuss organic amendments.
In the post-workshop surveys 100% of participants of the Flowering Tree field day responded "yes" that the workshop "improved my understanding of erosion control techniques" and 93% responded "yes" that the workshop "improved my understanding of compost applications on different landscapes." The participants reported that they would collectively share information about this project/workshop with over 500 others in the next 12 months.
In post-workshop survey, 100% of participants in the Tedord Farm field day responded that they "gained knew knowledge and/or built upon previous knowledge during the workshop", and 100% responded that "the workshop/event provided meaningful opportunities to connect and relationship build with other participants."
At the Sol Ranch field day, 100% of participants responded correctly to the two knowledge inventory questions defining sheet erosion and what a one rock dam are, but only 43% of participants felt confident in their "ability to strategize and prioritize erosion sites in areas where multiple erosion features are present" suggesting that the one-day workshop was useful for introducing the topic of erosion control but not sufficient to give participants confidence to do efficient work in new contexts.
No evaluation was conducted at Hibner field day due to a major rainstorm resulting in all of the vehicles getting stuck in the mud on the road and needing to be pulled out one by one by the host's tractor. Surveys from Esquibel ranches were misplaced.
Education and Outreach Outcomes
Successes
As mentioned previously, ranchers know that to build resilience, they need to be looking forward to when drought ends and severe weather occurs. For this reason, all of them have been eager to proactively address sites of active erosion and were excited to see how additional amendments could help. We all talked about what could be used from on-site in the future so they wouldn’t have to purchase commercial mulch or compost. We talked about using juniper branches, some people have food waste compost, and others already are interested in collecting and storing native seeds, so all of those activities may fit together in the future.
We appreciate the flexibility of WSARE grant administrators when we asked if we could move one workshop from our experimental site to that of a Tribal partner who had expressed interest late last year. Supporting Tribal-led efforts and interests supports Quivira’s work of becoming an anti-racist organization and so we were glad that we were able to think through how our existing funding could be used to advance the goals of Tribal partners.
Challenges
Our intern faced a big challenge when we analyzed all the data and found that there were no statistically significant effects of organic amendments despite high costs. She learned to present complex information with many unknowns (were they not effective because of drought? Would we see effects if we went back after a longer time than one year?) in a way that is helpful for producers (specifically, the rock structures are so effective on their own that people probably don't need to invest additional money into biological interventions).
Keeping water high on the landscape
How well organic material holds water