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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Water Management Research » Research » Research Project #436617

Research Project: Management Practices to Promote Soil Biological Health with Reduced Irrigation Inputs

Location: Water Management Research

Project Number: 2034-13000-013-005-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Jul 1, 2019
End Date: May 30, 2024

Investigate impacts of management strategies on soil microbial communities under standard and reduced irrigation inputs in agricultural systems.

Field trials incorporating varying management practices (i.e. biochar, compost, alfalfa, and cover crops) will be conducted with a range in irrigation treatments. Full irrigation to meet plant evapotranspiration rates (100%) and reduced irrigation (50%-75%) will be applied to treatment and control plots. Experiments will evaluate the influence of management practices on promoting soil health metrics and crop yields under the varying irrigation treatments. The diversity and biomass of soil microbial communities will serve as proxies of soil biological health. Soil samples collected from these projects will be analyzed to profile microbial community composition using soil DNA extractions and sequencing of bacterial/archaeal (16S rRNA genes) and fungal (ITS regions) taxonomic markers. Total soil biomass will be determined from DNA extraction yields as well as analyses of extracted phospholipid fatty acids (PLFAs). Microbially-produced extracellular polysaccharides (EPS) can reduce soil water loss and root drying and promote re-wetting of soil, offering an important benefit for crop productivity in soils with reduced irrigation inputs. Extracts of EPS will be collected from soil and serve as an indicator of community functionality under the varying management practices and irrigation treatments. All data will be statistically analyzed to reveal the capacity of the treatments to retain diverse and active microbial communities irrespective of the irrigation treatments. Additionally, statistical analyses will be employed to evaluate if community characteristics (e.g. taxa and/or traits) correlated with changes to crop yield and/or quality and to relate functionality data (e.g. EPS quantity and types) to yield results and microbial community compositions and biomasses. Results will contribute to a mechanistic understanding of microbial drivers of crop yield and resilience. From these insights, management practices that promote soil biological health and quality crop yield under reduced water inputs can be recommended. The project findings will be presented at annual soils conferences and professional meetings as well as distributed through extension activities.