By Isabelle Jenniches, NM Healthy Soil Co-Founder
Candelaria Nature Preserve encompasses 167 acres east of the Rio Grande in Albuquerque’s North Valley and includes the 38.8 acre Rio Grande Nature Center State Park. The property was purchased by the City of Albuquerque (CABQ) Open Space Division in 1978 for the purpose of creating a nature study area and wildlife preserve.
Initially, much of the land known as Candelaria Farm was used to grow alfalfa, but following concerns raised by local residents and development of a community-driven management plan in 2017, fields are now being transitioned to wildlife crops and native habitat. The goal is to create a mosaic reflecting the pre-engineering landscape of the Rio Grande valley with wetlands, riparian vegetation, and a mix of upland grasses and shrubs supporting a diversity of wildlife.
Implementation of this long term plan is a collaborative effort between CABQ Open Space Division, Ciudad Soil & Water Conservation District and Rio Grande Return. Rio Grande Return is a local nonprofit that specializes in habitat restoration. The district received a Healthy Soil Program grant from the New Mexico Department of Agriculture that included soil health improvements on a 2.8 acre field this winter. While access to Candelaria Nature Preserve is restricted to wildlife study, community science and restoration, the field functions as the preserve’s front door and you can get a sneak peek at what’s happening by peering through the chain link fence.
This particular field has a history of growing sunflowers and sorghum and was dominated by Johnson grass when Rio Grande Return started restoration work. Elms were encroaching at the edges. Soil health was poor after decades of tillage and chemical fertilizer use, the earth exhausted and devoid of life.
What are wildlife crops? Wildlife crops are cultivated not to be harvested for human consumption, but instead left in place for the benefit of wildlife, especially for migratory birds such as Sandhill cranes, snow geese, and others. Since many of these migratory birds travel hundreds or thousands of miles to overwinter and need to build fat reserves for the next breeding season, high-nutrition grains (e.g. corn, wheat, barley and oats) are especially useful wildlife crops. Other benefits are shelter and resources for local wildlife and soil health benefits.
To learn more about how to regenerate an old field like this, I spoke with Cameron Weber, Rio Grande Return’s Habitat Conservation Director. As stated in her bio, her focus is on “rewilding agricultural landscapes and ecological systems dependent on human participation”.
The goal for this piece of land is to create good quality resources for wildlife with special consideration for birds–including the iconic Sandhill cranes–and pollinators. The only form of irrigation is from the Duranes Lateral, the oldest acequia in Albuquerque. Soils are a fine sand covered by compacted silt-loam and very susceptible to wind erosion—underscoring the importance of keeping the soil covered.
Cameron explained the plan to create the right conditions to smother and decompose the Johnson grass–including seeds and clones–and benefit soil biology. Adapting an approach known as sheet mulching, unwanted weeds are suffocated under a thick layer of compostable materials, while their decomposing remains feed the recovering soil microbiome.
To begin with, the field was grazed by goats, mowed and surface tilled (only 1’-1.5” deep) where necessary. Slow-release amendments such as pelletized gypsum, kelp, and feather meal were applied to access nutrients that may be locked up in the soil and kickstart nutrient cycling.
Next, heavy-duty paper mulch was rolled out. A primarily recycled product is being offered under the name Weed Guard made by Sunshine Paper Company in Denver. The heavy-weight paper is about the thickness of a credit card. It was used successfully before in an agricultural production setting at Rio Grande Return’s seed farm and community garden. The paper mulch was effective in improving soil moisture retention and reducing weed competition. Entering the second year, it is still in place. (A similar product, Dewitt Weed Barrier, was not as effective.)
Weber and a group of volunteers then added bedding and animal manure from 300 goats provided by local contract grazier Galloping Goat Grazing, and topped it off in patches with straw, wood chips or native soil.
Because of the scale of the project and its overarching goal to encourage diversity, Weber is modifying the sheet mulching technique by applying materials unevenly. Thick layers of organic materials taper down to sparser cover or even just paper in some areas. She explains that sheet mulching builds great soil for gardening or farming, but in order to prepare the ground for a diversified native habitat, a patchwork of different “soil sponges” with varying infiltration rates is desired.
For example, a thick layer of straw is applied to create low, moist areas to be planted with wild plum and New Mexico Olive. In higher areas, goldenrod and desert willow will be planted to provide nectar for pollinators and perches for insectivorous birds.
Adjacent to this patchy sheet mulching, which covers at least one acre, Rio Grande Return has carved out a moist soil wetland where coyote willow, Gooddings willow and native riparian grasses will help to infiltrate water and support aging Rio Grande cottonwood trees nearby.
Using rolls of paper mulch is a good alternative to repurposed cardboard for projects beyond the backyard scale, but at about $186 by 5’ x 500’ roll, it is expensive. Funding through the Healthy Soil Program grant made it possible to purchase these materials as well as amendments.
The work was done in December 2022 and January 2023. Since then, the site has received no irrigation besides winter precipitation and results so far are looking promising. Simply by covering the soil, condensation can be detected underneath the paper! Timing is important—at a different time of year, this approach to soil restoration might require watering.
What are the next steps? To aid in the recovery of the soil sponge and provide symbiotic plant partners for the returning soil biology, native pollinator species and grasses will be seeded. The tough and dirty work is mostly done—if you would like to lend a hand, you’re invited to volunteer!
If you’d like to get involved at Candelaria Nature Preserve, you can reach out to the Friends of Candelaria Nature Preserve at email@example.com. Weekly volunteer opportunities and a monthly tour are available to all. Rio Grande Return also provides various opportunities to help with native habitat transformation and restoration. You can reach Cameron Weber at firstname.lastname@example.org.
NMDA’s Healthy Soil Program
The Healthy Soil Program administered by the New Mexico Department of Agriculture is currently accepting applications from Individual Applicants (deadline is April 21, 2023 at 12 p.m. noon) and Eligible Entities (deadline is May 17, 2023).
CLICK HERE to learn more about the Healthy Soil Program at NMDA’s website.