Location: Columbia Plateau Conservation Research Center
Project Number: 2074-11120-005-011-A
Project Type: Cooperative Agreement
Start Date: Sep 16, 2025
End Date: Sep 15, 2026
Objective:
Conduct research and develop approaches to increase soil carbon or improve related soil properties (e.g., soil health; functional optimization of the soil microbiome) that are marked by increased dryland production, while at the same time lowering inputs and improving resilience to weather-related stressors. Specifically, 1) carry out a comprehensive assessment of the soils and crops in the Pendleton long term experiments (LTEs), and 2) assess how changes in soil C stocks and soil health indicators in the different LTEs affect dryland grain yields and quality, and weed pressure, and to 3) quantify C sequestration in dryland agricultural systems, with emphasis on how N fertilizer and weed control (tillage vs no-till) factor into the carbon balance of a farming operation, within and beyond the farm gate.
Approach:
Objective 1 will be evaluated at the co-located ARS and Oregon State University (OSU) research station near Pendleton, Oregon. This will involve a detailed assessment of the soils and crops in LTEs. Soil samples will be obtained at several depth increments down to rooting depth, in selected treatments. We plan to quantify a variety of organic and soil C fractions, including mineral-associated organic matter and particulate organic matter, and soil health parameters, including soil total carbon and nitrogen, soil acidification, electrical conductivity, and bulk density. In addition, soil samples will be scanned in the mid infrared to examine changes in the molecular structure of soil organic matter. The mid-infrared spectral data will also be used to develop calibrations for bulk soil C, soil C fractions, and soil health parameters, including soil texture, soil pH, and liming requirement, which will facilitate the high throughput analysis. The soil analyses will help determine how different tillage intensities, crop rotations, fallow frequency, and residue management practices affect C cycling, C redistribution within the soil profile, and soil health.
Objective 2 will assess how changes in soil C stocks and soil health indicators in the different long-term experiments at Pendleton affect dryland grain yields and quality and weed pressure. We will investigate how interactions among soil properties, organic matter fractions, and biological processes influence crop yields and cop quality (e.g., grain protein), to support the development of dryland agricultural systems that minimize soil degradation. Crop and weed biomass and weed cover will be recorded at crop maturity in the tillage and fertilizer treatments of the different experiments. Wheat grain yields, as well as grain protein concentration, test weight, and nutritional parameters will also be determined at harvest.
Objective 3 will quantify C sequestration in dryland agricultural systems, with emphasis on how tillage, residue management, fallow periods, N fertilizer and weed control (tillage vs no-till) factor into the carbon balance of a farming operation, within and beyond the farm gate. We will conduct life cycle (LCA) calculations in the initial stage of wheat production, primary covering raw material and on-farm practices, while planning to expand the analysis to include industrial processes and transportation. We aim to optimize input use (i.e., fertilizer, fuel, machinery) to reduce costs and enhance competitiveness in sustainable markets. The data will be used to inform growers about how different farming practices affect soil health. This work will establish the potential for soil conservation practices to be adopted, weighing expected economic income vs. risk.