Biogeochemical components and climate vulnerability

Component Lead:
Sanford Eigenbrode

Potential adaptation and mitigation strategies

Component Lead:
Erin Brooks

Drivers, vulnerabilities, or resiliencies of the socio-economic system

Component Lead:
Clark Seavert


Objective 1:  Agronomic assessment (crop and soils)

Investigators: Kurtis Schroeder, Rebecca McGee, Ian Burke, Sanford Eigenbrode, Jodi Johnson-Maynard, David Huggins

Problem and justification:

Agriculture in the inland Pacific Northwest (iPNW) has been characterized by high inputs and intensive wheat production with near monocultures of wheat in the drier parts of the region. Given escalating concerns over climatic variation and soil health, farmers are interested in crop diversification. Relatively new varieties of winter pea and cover crops are of interest, but little research has been conducted on optimizing growth and quality of these crops. Information such as optimum seeding dates and rates, planting depths, and weed and insect pressure and control is needed to increase adoption of these alternative crops. In addition, knowledge of how these alternative crops impact soil health and productivity over longer time scales is needed.

Research approach:

A combination of field plots located in two different agroclimatic zones (Genesee, ID and St. John, WA) and greenhouse studies are currently being conducted to optimize agronomic management of two alternative crops: winter pea and cover crops. All measurements—soil health indicators, weed and soil and surface dwelling micro-arthropod populations, crop biomass, forage/crop quality, and yield—are being taken at the same replicated strip plots at each site to ensure a comprehensive assessment of the impact of these crops on yields and long-term resiliency to climate change. Greenhouse and laboratory work is also being conducted to better isolate the performance of new winter pea cultivars under varying environmental conditions and determine other benefits of crop diversification.

Objective 2:  Crop influences on nitrogen and water use efficiency and greenhouse gases

Investigators: Erin Brooks, Shelley Pressley, David Huggins

Problem and justification:

Future climate change and long-term soil degradation limit the sustainability of business-as-usual crop management strategies in the iPNW. Alternative crops and rotations must not only be profitable in the short-term, but be resilient to changes in water and nutrients. In addition, the impact of crop diversification on the release of greenhouse gases must be documented and utilized in the assessment of new crops. The primary goal of work under this objective is to determine the biophysical and biogeochemical consequences of the "business as usual" approaches for wheat production in the iPNW compared to alternative, diversified and intensified systems using field experimentation, field monitoring, and modeling.

Research approach:

A multi-scale, integrated observational approach coupled with modeling is being employed to construct nitrogen and water budgets using the field-scale business as usual, winter pea and cover crop/grazing treatments in the replicated strip trials located at both St. John and Genesee. In addition, carbon dioxide and water vapor flux from alternative and business as usual crops are being measured in 25 hectare fields using Eddy Covariance Flux Towers. The towers measure carbon dioxide, water vapor, wind speed, net radiation, air temperature, and soil moisture, allowing for detailed calculations of the net storage or release of carbon over the growing season and are co-located near the strip trial plots at both sites. Real-time data from each of the flux towers can be seen here.

Objective 3:  Impact of alternative crops and rotations on yields and profitability

Investigators: Kurtis Schroeder, Clark Seavert

Problem and justification:

Profitability is a major influencing factor in whether or not a farmer will adopt a new practice or crop. Currently, little economic data exists for winter pea or cover crops. At the same time, a large percentage of agricultural producers do not have the managerial accounting information to develop meaningful cost of production budgets. New tools are needed to assist growers in determining the advantages and risks of crop diversification.

Research approach:

Existing production budgets will serve as a basis for conducting an investment analysis that will determine whether alternative uses for agricultural producers' land would be more profitable than the business-as-usual practice. Agronomic data collected from the replicated strip trials at both locations will be utilized to construct budgets and determine the profitability of crops as well as the business as usual and diversified rotations. AgBiz Logic, an economic, financial and environmental decision tool designed for producers to measure the profitability and feasibility of alternative investments and assess current leasing arrangements, will be parameterized and made available for growers to aid decision making processes.

Objective 4:  Identify the impact of on-farm and surrounding land use on weed and insect populations

Investigators: Sanford Eigenbrode, Ian Burke

Problem and justification:

Consequences of introducing new crops may extend beyond the boundaries of individual farms and significantly impact other crops and land uses across landscapes. These impacts can include the spread of specific weeds, insect pests and beneficial organisms. Further study and documentation of these populations in alternative crops across the region, therefore, is required.

Research approach:

Work under this objective is focusing on cover crops. A total of 10 grower-owned and managed fields located across the study area are being studied under this objective. All sites had cover crops planted adjacent to winter wheat, the business-as-usual crop. Sweep net sampling is being used to study populations of insect pests and beneficial organisms such as pollinators. Cover crop biomass and potential returns of organic matter and nutrients to the soil are also being quantified.