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ARS Home » Pacific West Area » Corvallis, Oregon » Forage Seed and Cereal Research Unit » Research » Research Project #437866

Research Project: Understanding the Link Between Management History, Soil Health Status, and Below Ground Biological Functions in Grass Seed Cultivation

Location: Forage Seed and Cereal Research Unit

Project Number: 2072-12620-001-011-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Apr 1, 2020
End Date: Dec 31, 2021

Develop knowledge regarding the influence of crop management practices on yield, soil health, and the plant microbiome.

Correlating yield with soil health metrics: Preliminary data will be collected by identifying and collaborating with grass seed growers in the South Willamette Valley. A questionnaire that helps growers self-identify fields that have poor, average, or above average soil qualities will be developed and deployed. A subset of these fields will be chosen for subsequent sampling and analysis. Soil samples will be collected according to the protocols outlined in the Cornell Assessment of Soil Health. Samples will be examined using in-house, ARS, and commercial laboratories for a suite of biological, chemical, and physical parameters. The results of these measurements will be analyzed, and will either corroborate or refute grower perceptions of soil health. Soils with “good” or “poor” soil health metrics will be collected from a subset of the fields to evaluate yield potential. Greenhouse trials will determine if soils with variable qualities have different yield potentials. To determine this, intact soil cores will be collected, transported to the greenhouse, and planted either with annual ryegrass or Tall Fescue, according to established protocols. Intact cores will be amended with fertilizer to meet extension recommendation to account for any inherent nutrient deficiency or differences in nutrient management. Plants will be grown under supplemental lighting until maturity and plant growth regulators applied to mimic field additions. At the conclusion of the experiment, the above and belowground biomass will be harvested and measured to determine total plant and seed yield. Correlating soil health with microbial community composition: Soil cores from the existing greenhouse trial will be analyzed for post-harvest fertility metrics and biological function. In addition to the analyses performed on bulk soils, DNA will be extracted from both the bulk and the rhizosphere soil. The rDNA from both soil compartments will be amplified using canonical 16S and ITS primers. The DNA samples will then be sent to the Center for Genome Research and Biocomputing at Oregon State University for quality control, library preparation, and DNA sequencing. The resulting data will be analyzed using existing R pipelines to describe and compare the microbial population in each field, for each plant. Colonization by arbuscular mycorrhizal fungi (AMF) will be further assessed by microscopic quantification of root segments.