The Use of Biochar in Drought, Wildfire and Climate Change Mitigation – A Field Trial in Eureka County, Nevada

A note for our readers: the views reflected by the authors do not reflect the views of ASPA. 

By Frederick Steinmann

In early 2014, the United States Department of Agriculture listed several Nevada counties as primary natural disaster areas due to the ongoing drought. Agricultural interests have been particularly hard hit as drought conditions have persisted for a number of years causing severe economic hardship in communities that rely on farming and ranching as primary drivers of economic activity. In Eureka County, Nevada, agriculture and natural resource extraction represent the largest portions of the county’s economy. Diamond Valley, located centrally within Eureka County, has the largest concentration of agricultural production, producing mainly alfalfa and timothy hay for export. Barrick Gold Corporation’s Ruby Hill Mine is located on the southern tip of the Diamond Valley and the town of Eureka, the county’s largest urban settlement, is located adjacent to the mine.

Eureka County faces the confluence of two perfect economic storms that threaten the long-term sustainability of agriculture and mining in the county. The ongoing drought in the western United States and in Eureka County, coupled with a history of over-appropriated water rights in Diamond Valley, has pushed the Diamond Valley aquifer to the brink of collapse. According to the Nevada Division of Water Resources in 2014, the water level of the Diamond Valley aquifer, which is used for agricultural, mining and municipal uses, has fallen by 23 feet in overall water level elevation over the past nine years. In some places, it has fallen as much as 100 feet.

According to the Nevada Division of Water Resources, the estimated annual recharge of the aquifer is approximately 30,000-acre feet of water per year. However, allocated groundwater rights associated with the aquifer total approximately 131,150 acre feet of water per year with 95.0 percent (124,700 acre feet) used for agricultural irrigation and 2.5 percent (3,300 acre feet) used for mining and milling purposes. The state engineer has requested that water right holders in Diamond Valley reduce overall irrigation and use of water by approximately 60.0 percent over the next 50 years. This reduction could threaten the sustainability of agricultural production in Diamond Valley and the county’s overall long-term economic viability.

The second threat facing Eureka County’s economic viability has been the sudden sharp decline in the price of gold and other precious metals, which has led to the accelerated closure of the Ruby Hill Mine. According to the U.S. Federal Reserve, the price of gold peaked in April 2013 at an estimated $1,472.75 per troy ounce. As of June 2014, it has fallen to an estimated $1,261.75 per troy ounce. The decline in the price of gold, coupled with a high wall failure in 2013, led to the closure of the Ruby Hill Mine and Barrick Gold Corporation has started its remediation and post-mining planning efforts. These efforts include reclamation of the mine tailing piles produced as a result of the open pit mining. Mine tailing piles often experience slides and severe erosion as the soils themselves contain little to no active microbial activity. Large shrubs and native plants and grasses are unable to grow on the tailings due to the lack of microbial activity in these sterile soils. Wildfire risk associated with the tailings is also high as cheatgrass and other invasive plants and weeds are able to grow in the tailings.

In response to these needs, University of Nevada Cooperative Extension faculty, in partnership with the Eureka County Department of Natural Resources, the Nevada Department of Agriculture, the U.S. Department of Agricultural’s Agricultural Research Service, the U.S. Forest Service, the Eastern Nevada Landscape Coalition and the Nevada Department of Wildlife, is currently conducting a three-year biochar production field trial and demonstration project. Biochar is a carbon-rich material with a chemically and microbially stable molecular structure that has been used in soil reclamation, agricultural production and carbon sequestration efforts. Past research into the use of biochar as an agricultural and soil amendment indicates several benefits including increased soil moisture retention, increased microfauna reproduction, improved germination of native plants and increased nutrient availability. Started in 2013, the three-year biochar field trial is designed to test these potential benefits as a response to ongoing drought conditions in Nevada and throughout the western United States, and as a way to mitigate the potential threats of erosion and wildfires associated with mine tailing piles as part of a post-mine mitigation plan.

Biochar is produced through a pyrolysis process using some type of biomass and feedstock. In Eureka, invasive pinyon and juniper trees that have encroached on threatened sage grouse habitat will be used as the biomass input. In addition to biochar, a bio-oil, similar to crude oil though not as refined, and a synthesis gas (biogas) are produced as byproducts of the pyrolysis process. While the bio-oil and biogas can be used as an alternative energy source, further refined to produce a crude oil substitute, or used as a hydraulic fluid or mechanical lubricant, past research suggests that biochar itself has three primary benefits:

1. Biochar, as a soil amendment in agricultural purposes, has demonstrated the ability to produce similar crop yields using less water.
2. Biochar, as a soil amendment in sterile soils, has demonstrated an ability to improve overall soil microbial levels leading to improvement in overall soil conditions so that larger and more complex forms of plant life can grow.
3. Biochar, as a soil amendment, can be used as a carbon capture devise and as a climate change mitigation strategy. 

The field trial will also explore the economic feasibility of biochar production as a new industry. In response to declining mineral extraction activities in the county, this field trial will explore the potential uses of the bio-oil and biogas byproducts and estimate the potential costs associated with biochar, bio-oil and biogas production.

Biochar has demonstrated its ability to conserve water in agricultural production and improve soil microbial levels in sterile soils. However, past research into biochar, bio-oil and biogas production has largely been confined to laboratory experimentation and the Eureka County field trial and demonstration project is expected to add to the growing interest in biochar as a drought management strategy, a wildfire and soil erosion management strategy and as a climate change mitigation strategy.

 

Author: Frederick Steinmann is an assistant professor in the College of Business Administration at the University of Nevada, Reno. Steinmann earned his doctorate in Policy, Planning, and Development from the University of Southern California in 2010. He received both B.S. and M.S. in Economics from the University of Nevada, Reno. He can be reached at [email protected].

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