Location: Columbia Plateau Conservation Research Center
Project Number: 2074-21600-001-000-D
Project Type: In-House Appropriated
Start Date: Sep 6, 2023
End Date: Sep 5, 2028
Objective:
Objective 1: Evaluate and seek to optimize climate-adaptive cropping system alternatives to the 2-year winter wheat-fallow system that reduce fallow periods in the dryland Pacific Northwest, increasing productivity, profitability, input-use efficiency, and sustainability.
1.A: Evaluate winter cover crops in low and intermediate precipitation regions.
1.B: Evaluate newly developed food-grade winter field peas as a rotational crop with nitrogen benefit.
Objective 2: Increase resilience and profitability of the widely-used dryland wheat-fallow system by improving nutrient and weed management.
2.A: Develop liming practices to ameliorate the increasing soil acidity issues on wheat production systems in the low and intermediate regions of the PNW to increase productivity and yield.
2.B: Evaluate the effects of crop management on soil and grain nutrients.
2.C: Evaluate the impacts of integrated (chemical/mechanical) weed management and weed physiology on soil water dynamics in-field and under controlled settings.
2.D: Evaluate profitability of management strategies that ameliorate soil quality decline (e.g., soil pH) or reduce weed infestation.
Objective 3: Develop tools to better assess agricultural soil microbiomes for enhancing nutrient cycling and optimizing desired biochemical degradative pathways in diverse agroecosystems.
3.A: Develop high-throughput standard protocols to assess soil biological function and diversity.
3.B: Assess the soil microbiome response to PFAS as an emerging concern in agriculture.
Approach:
1.A: A dryland cover crop systems trial under low and intermediate rainfall will include fall-seeded cover crops of winter pea, winter canola, winter barley, and a mix of the three. Winter wheat-fallow will be the control. Analyses include grain yield and quality; cover crop and weed biomass, density and/or cover; soil fertility and soil biology; soil water dynamics; and economic assessments.
1.B: Studies will be established at two dryland sites under low and intermediate rainfall and an irrigated site. Treatments include food-grade green pea (MiCa), a food-grade yellow pea (Klondike), and a non-food-grade Austrian winter pea (Grainger), plus wheat and fallow. Analyses include plant phenology and growth; yield components; plant nitrogen and nitrogen fixation; soil fertility; soil moisture; and soil biology. Data will support development of the first mechanistic plant growth model for winter field peas (DSSAT CROPGRO; collaboration with University of Florida).
2.A: A lime micro-dosing method will be evaluated in dryland wheat cropping systems at sites with soil acidity constraints (pH <5.5) in the low and intermediate rainfall regions. Treatments will include a one-time application of lime using the traditional broadcast approach or micro-dosing with 10-50% lime recommendation. Analyses include soil chemistry (including exchangeable aluminum [Al3+], pH, and cation exchange capacity) and grain yield.
2.B: Archived soil samples from a long-term fertility trial at Pendleton, Oregon will be analyzed for secondary- and micro-nutrient contents and soil pH to identify historical trends in soil quality and crop yield. Separately, the effects of wheat genotype, production environment, and other variables on grain nutrient density will be assessed.
2.C: Weed management with chemical, mechanical or integrated (chemical/mechanical) practices will be assessed in dryland wheat-fallow under low and intermediate rainfall. Assessments include weed density, vegetation cover (UAV-based); grain yield; and soil water dynamics. Greenhouse and column assays will assess the potential belowground advantage of weeds on water extraction compared to wheat including permanent wilting point, rooting depth, and soil water extraction.
2.D: Standard enterprise budget analyses will be performed to determine cost-benefit relationships from lime micro-dosing and integrated weed management strategies.
3.A: A bench-scale assay for combined nutrient-cycling enzymes (carbon, nitrogen, sulfur, phosphate) will be modified for microplates with robotic-assisted liquid handling. Protocols and bioinformatic pipelines will be developed to assess archaeal and bacterial ammonia-oxidizing microbial communities based on DNA sequencing of the amoA gene (ammonia monooxygenase) using the Oxford Nanopore MinION platform.
3.B: Microbial communities from PFAS-contaminated and PFAS-naïve soils amended with PFAS will be assessed using molecular techniques to identify potential microbiota associated with PFAS degradation. PFAS compositional profiles and concentrations will be determined using liquid chromatography mass spectrometry.
