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Study Underway to Understand Dynamic Soil Properties in a California Orchard

Ragbir Atwal-1To better understand how static soil properties characterized by soil surveys change under various uses and management, a five-year soil study is being conducted on the property of Ragbir Atwal, a Sutter County prune farmer. The results of the study may help to effectively meet the dual goals of sustained productivity and soil function.

At left: Ragbir Atwal, the project host, first worked with NRCS when he participated in the Bay-Delta Initiative and EQIP to convert from flood irrigation to micro sprinklers in 2013. “He’s a really good cooperator and innovator and very interested in conservation,” says Soil Conservationist Gabe Garbarino. 

The soil study integrates a conservation technical assistance request from Sutter County RCD for evaluating the effect of cover crops on nutrient and irrigation water management with ongoing Chico Soil Survey update activities in the Sacramento valley. It also fits into a NRCS national team effort to document key soil properties that have been shown to affect soil performance under various soil management strategies. This is the second year of the study, which is part of the National Soil Health Initiative.

Land preparation and management practices in northern California fruit orchards alter critical soil properties and functioning, disrupting water, air, nutrient, and carbon cycles.  This can result in accelerated soil erosion and runoff, off-site delivery of nutrients and chemicals, increased production costs, and reduced soil productivity.

Ragbir Atwal-2Over a five-year period the study will monitor and evaluate near-surface soil property response to three commonly-applied management scenarios in northern California orchard floor management that can influence soil fertility, soil organic matter, and water infiltration.

At right: Atwal Prune orchard during harvesting in 2014.


The three types of management being tested are clean till, resident vegetation, and winter annual cover crop mixture. The study will include an evaluation of the Soil Health Nutrient Tool (Haney Test) in California. The project targets the moderately extensive Tisdale soil series, commonly used to produce prunes.

“This is a groundbreaking project,” said Soil Conservationist Gabe Garbarino. “Not much has been done on orchards soils before. The most interesting thing will be to see the difference between resident veg treatment and cover crops.”

Ragbir Atwal-3Area Resource Soil Scientist Jim Komar is project leader for the study. Ryan Miebach, MLRA Soil Survey Leader, MLRA2‐2, from the Chico Soil Survey Office is co-project leader. Cooperators include the Sutter County RCD and staff of the NRCS field office in Yuba City.


At left: Resident vegetation ground cover plot in Atwal’s orchard in Aug. 2015.


“Locally, this work adds support to the recommendations NRCS field offices give cooperating producers when planning for orchard floor management concerns,” said Komar. “More broadly, this work aids in the establishment of protocols for cataloging dynamic soil properties, furthering our ability to predict the effects of management on critical soil functions.”