Soil health is fundamental to sustainable intensification of agricultural productivity that is necessary to meet demands of a growing human population without degrading ecosystem functionality (Struik and Kuyper, 2017).  Soil health can be defined as the ability of soil to sustain plant and animal productivity, maintain or enhance water and air quality, and support human health and well-being (Karlen et al., 1997), and is typically quantified with respect to soil physical, chemical, and biological attributes. Thus, healthy soils support optimal productivity, maintain biodiversity, support climate-resilient agricultural enterprises, sequester atmospheric carbon to mitigate global warming, ultimately providing the foundation for sustainable intensification (Paustian et al., 2016).

In order to help maintain sustainable agroecosystems, over the last decade (~ 2010 to 2020), a USDA-sponsored initiative successfully generated a great deal of excitement around soil health. But zeal to implement soil health farming practices outpaced identification of sound soil health assessment methods and sometimes led to claims that overreached what could be accomplished in terms of organic matter accumulation, optimal biogeochemical cycling to maintain productivity, or other soil attributes, especially for soils of the arid and semiarid western US. More recently, the NRCS Soil Health Division, the Soil Health Institute, and university and federal researchers have begun to scientifically develop effective, environment-specific, chemical, physical, and biological assessment methods, or to identify and refine those developed over the last 40 to 50 years (e.g., Norris et al., 2020; Cornell University, 2020; Soil Health Institute, 2020a; USDA-NRCS, 2011; Stott, 2019).

As such, soil health assessment is becoming an effective indicator of management system sustainability (e.g., Ippolito et al., 2017; Karlen et al., 2014; Stott et al., 2012) and federal and state agencies are developing inventory and incentive strategies. But the many combinations of soil type, regional climate, management history, economic drivers, time, and variable climate change trajectories do not follow state or other jurisdictional boundaries, meaning that the most effective soil health assessment tools vary from place to place, over time, and cross US state boundaries. Water-constrained systems of the western states, with inherently low organic matter and at times high salinity, require different approaches toward assessment than more humid regions. The multi-state research project proposed here would implement a coordinated strategy to identify best soil health management and assessment approaches for western US production systems.

The WDC52 workgroup currently includes scientists and educators from across the western US within and outside the State Agricultural Experiment Station System, many of whom have decades of experience assessing soil health and quality in many western crop and livestock production systems.  Representation consists of the following land grant institutions:  the University of Hawaii, Washington State University, Oregon State University, the University of California – Davis, the University of Idaho, Utah State University, Montana State University, the University of Wyoming, New Mexico State University, the University of Nebraska, Kansas State University, and Lincoln University in Missouri.  Two Soil Health Institute scientists representing the western US, and one soil scientist from the USDA-ARS in Fort Collins, Colorado, also comprise the current workgroup.  We have reached out to the USDA-NRCS for western US representation (Dr. Rachel Seman-Varner, NRCS National Soil Health Specialist), so our workgroup efforts align with those of the NRCS. Members of this multi-state research group propose to investigate those soil physical, chemical, and biological attributes necessary to maintain sustainable agricultural intensification in the western US over time.  Collaborative investigations and data sharing will generate needed knowledge, and identify knowledge gaps, to develop and promote healthy western US soils while minimizing the potential for unintended negative consequences (e.g., off-site nutrient, erosional, and yield losses, etc.). 

Justification:

Acknowledging the principles and practices that promote improvements in soil physical, chemical, and biological attributes in order to create sustainable, resilient agroecosystems is the epicenter of soil health.  More importantly, fully understanding the interplay and intricacies between these three soil components within the context of managed agroecosystems, over time, is paramount for feeding, clothing, and fueling an ever-expanding human population, while reducing environmental degradation and the human footprint.

Although this newly created Western Development Committee has yet to perform collaborative research with respect to soil health issues in the Western US, many within the Committee have worked with one another in the past or are currently collaborating.  All members of the committee currently have projects that focus on various aspects of soil health.  Numerous research examples listed below all have a direct soil health focus:

• Jim Ippolito (Colorado State University): 1) multi-location projects focused on BMPs and edge of field water quality; 2) multi-location biosolids land application projects (part of the Soil Health Institute North American Project); 3) wheat-fallow versus wheat-corn-fallow rotations; 4) dairy manure amendments for improving degraded agricultural land; 5) quantifying benchmark soils for soil health in the central High Plains (with PI Norton, the University of Wyoming); 6) heavily involved in the newly formed (2019) state of Colorado Collaborative for Health Soils Initiative at the state level; 7) co-lead of WDC52;


• Jay Norton (University of Wyoming): Use of labile soil C/N pools as soil health indicators in 1) long-term cheatgrass invasion; 2) cover crops and other alternatives to traditional high plains wheat-fallow rotations; 3) integrating cover crops and annual forages into intensive irrigated sugarbeet-small grain rotations; and 4) improving ecosystem service provision in high-elevation grass/hay meadows. Norton is also 5) leading initiation of a state-wide soil health strategy for Wyoming and 6) is co-lead of WDC52;


• Jonathan Deenik (University of Hawaii): 1) works across soil mineralogical classes in south Pacific islands; 2) soil organic C alterations in south Pacific islands. Awarded NIFA grant in 2017 “Putting the farmer in the driver's seat: Integrative web tool for improved soil health and carbon assessment, monitoring, and planning” which has identified 11 soil health indicators suitable across range of mineralogy. The long-term goal is to engage and empower farmers and land managers to improve soil health and promote carbon sequestration through the implementation of an individualized, yet routine soil test and the development of an interactive web-based data and information management and planning tool. Awarded NIFA grant 2020 “An emergent soil health framework for agroecosystems in underrepresented tropical/subtropical islands or regions” with a framework that highlights 1) interlinkages among soil biological, chemical, and physical properties and 2) areas where further action is needed to improve agricultural practices across a wide diversity of soil types in tropical/subtropical islands or regions Hawaii, Puerto Rico, and Pohnpei). Awarded USDA-CIG 2020 “Producer-driven implementation of Soil Health Management Systems adapted to diverse cropping systems in tropical and subtropical island regions.”;


• Deirdre Griffin Lahue (Washington State University): 1) specialty crops (e.g., wine grapes, potatoes, sweet corn, etc.) – soil indicators – yield; 2) biosolids land application (part of the Soil Health Institute North American Project);


• Tarah Sullivan (Washington State University): 1) various crops/varieties and their influence on soil microbial community structure and function; 2) pennycress;


• Zachary Kayler (University of Idaho): 1) Intercropping approaches to soil health; 2) Pacific northwest dairy operations and soil health; 3) watershed level studies of conservation agriculture; 4) no-till demonstration at WSU RJ Cook Agronomy farm;


• Jodi Johnson-Maynard (University of Idaho): 1) alternative cropping rotations under various precipitation regimes; 2) transitions to certified organic production agriculture; 3) appropriate soil health targets; 4) soil health research and training farm at the new University of Idaho Dairy center in southern Idaho;


• Markus Kleber (Oregon State University): 1) CASH-type soil health project focused on soil indicator scoring functions; 2) soil C storage;


• David Myrold (Oregon State University): 1) Can soil microbial communities be used to quantify soil health; 2) soil health of diverse agricultural systems (e.g., Christmas trees, vineyards, hazel nut orchards, perennial grass-seed, potatoes); 3) soil health in forested ecosystems;


• Sanjai Parikh (University of California, Davis): 1) biochar land applications; 2) amendment use to increase soil C storage across the state of California; 3) knowledge to policy at the state of California level; 4) project lead of the UC Davis Global Soil Health Portal (available at: http://soilhealth.ucdavis.edu/);


• Grant Cardon (Utah State University): 1) irrigated western US soils/salinity issues; 2) soil C accumulation under no-till grain production; 2) biosolids land application; 3) oil/gas pad reclamation; 4) orchard cropping systems;


• Matt Yost (Utah State University): 1) 10-16 approaches to water management, optimization; 2) previous experience with the Soil Health Partnership, their indicator database, and soil health tests for data correlation analyses; 3) cover crops and/or interseeding; 4) member of the State of Utah Soil Health Partnership;


• Clain Jones (Montana State University): 1) long-term cropping system by inorganic N fertilizer rate studies; 2) western US soil acidification issues;


• John Idowu (New Mexico State University): 1) numerous cropping systems, management, and land resources areas research, in conjunction with streamlining soil health indicators; 2) tillage management and short-term soil alterations; 3) soil amendments (e.g., pecan waste) and irrigation; 3) cover crop research; 4) weed control; 5) soil health and greenhouse gas emissions in dryland or irrigated systems; 5) halophytes;


• Bijesh Maharjan (University of Nebraska): 1) identifying the soil health gap (e.g., where agroecosystems are versus where they could be); 2) long-term agroecosystem research (part of the Soil Health Institute North American Project);


• Augustine Obour (Kansas State University): 1) grazing cover crops in dryland agroecosystems; 2) tillage or strategic tillage and crop rotations effect on soil properties; 3) Multi-state on-farm regenerative agriculture research across Colorado, Nebraska and Kansas;


• John Yang (Lincoln University, in Missouri): 1) soil remediation; 2) nano-particle soil applications; 3) leads a soil health program on campus;


• Frieda Eivazi (Lincoln University, in Missouri): 1) enzymatic indicators; 2) small farmers (1-10 acres), organic, no-till cover crops research; 3) cover crop termination timing within cropping rotations;


• Tunsisa Hurisso (Lincoln University, in Missouri): 1) soil indicators and multiple sources of variability; 2) biologically-active soil organic matter and agronomic outcomes; 3) cover crop-based no-till vegetable production systems; 4) cover cropping and rotational strategies in transitions to certified organic agriculture;


• Catherine Stewart (USDA-ARS, Fort Collins, Colorado): 1) soil C and C fractions, nutrient cycling; 2) crop residue management in no-till irrigated cropping systems; 3) manures, biochars, biosolids research;


• Shannon Capellazzi and Dr. Daniel Liptzin (Soil Health Institute): 1) North American project to evaluate soil health metrics; 2) soil health metrics with respect to management; 3) deep C pools project; 4) soil health targets; 5) economic analysis; 6) scalable suite of indicators to provide pertinent soil health information to producers, especially with respect to economic return.

Utilizing the strength of the above members and dozens of soil health projects, a multi-state research group will facilitate a coordinated regional effort to develop and evaluate soil health indicators using a sound, co-designed scientific approach that results in a minimum data set of indicators for each soil-climate-management system scenario. Meetings of representatives from western Land-Grant universities, state and federal agencies, and others will foster exchange of ideas and approaches, as well as collaborative sub-regional projects.