California Institute for Water Resources
California Institute for Water Resources
California Institute for Water Resources
University of California
California Institute for Water Resources

Climate-smart actions and indicators for increasing available water capacity of California soils

Summary:

Facing drought and climate change, California growers are regulated and incentivized to increase irrigation efficiency and build soil health through statewide policies and programs. However, there is a knowledge-action gap between soil health best management practices and increases in soil available water holding capacity needed to alter irrigation management. Unknown and unanticipated water costs and unclear irrigation benefits have been identified as reasons why soil health BMP adoption is low, and we address key barriers to adoption that have great potential for improving water conservation and long-term drought resilience of California agricultural systems.

Investigator:

Mallika Nocco
Assistant Cooperative Specialist, Land, Air, and Water Resources
University of California Davis

Project description:

Facing drought and climate change, California growers are regulated and incentivized to increase irrigation efficiency and build soil health through statewide policies and programs. Growers who participate in the Healthy Soils program are heavily incentivized by water-related soil health benefits such as increases in soil available water holding capacity, infiltration, drainage, and decreased irrigation costs.

However, there is a knowledge-action gap between soil health best management practices (BMPs) and increases in soil available water holding capacity needed to alter irrigation management. Because of this knowledge-action gap, growers do not have the decision support they need to assess when BMPs have increased available water holding capacity enough for them to start using less water for irrigation. Co-benefits have been mentioned broadly in the California Healthy Soils Action Plan, but practical tools and metrics to co-manage water, soil health, and C-sequestration are needed.

Unknown and unanticipated water costs and unclear irrigation benefits have been identified as reasons why soil health BMP adoption is low in California. We address key barriers to adoption of soil health BMPs that have great potential for improving water conservation and long-term drought resilience of California agricultural systems. We are conducting a meta-analysis to quantify the costs and benefits of different agricultural BMPs on available water capacity, critiquing methods and metrics for quantifying available water holding capacity in soil health projects, and developing more accessible metrics of available water holding capacity assessment that can demonstrated to growers in the field in order to advance changes to irrigation practices.

Outcomes will clarify water costs and irrigation benefits to ultimately lead to increased adoption of soil health BMPs for actionable water conservation. We anticipate developing a new prototype for assessing soil available water holding capacity in the field and new soil health and irrigation extension workshop materials for both remote and in-person delivery across a variety of grower groups.

 

Nocco

Undergraduate researcher Cassandra Bonfil in the field.
Undergraduate researcher Cassandra Bonfil in the field.

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