Impacts of Native and Introduced Cover Crops on Soil Health in a Table Grape Vineyard of the San Joaquin Valley
Margaret Fernando,* Lauren Hale, Anil Shrestha,
and Sharon Benes
*California State University, Fresno, 5368 N 6th Street, apt 105,
Fresno, CA, 93710 (margierfernando@mail.fresnostate.edu)
Cover crops are a component of sustainable agriculture, but their adoption in California is fairly low compared to other parts of the United States, primarily due to concerns over water use by the cover crops and diverse cropping systems. This study was conducted to determine how cover crops could be managed efficiently in a newly established Autumn King table grape vineyard in the semi-arid climate of the Eastern San Joaquin valley. The impacts of native species cover crops (Phacelia tanacetifolia) and introduced species cover crops (Secale cereale L. ‘Merced’) on soil health, crop water dynamics, and grapevine development were studied at the USDA-ARS at Parlier, CA. These cover crops were planted in vineyard inter-rows and the cover species were chosen for characteristics deemed beneficial to vineyards, such as ease in establishment, ability to attract beneficial insects, and low or non-competitiveness for soil water. In 2020, soil moisture in the native cover treatment averaged 15% more than in the introduced treatment and 41% more than the bare treatment, a trend that was retained even after irrigation run times were decreased in the native cover treatments. Vine vigor, a common assessment of vine health, was measured in December 2020. The average shoot mass, trunk diameter, and shoot mass per vine length were greatest in the native treatment. Soil aggregates assessed in 2021 showed that the percent soil mass of native treatment plots in the 2 mm fraction was 7.3% more than in the introduced and 7.9% more than the bare treatment. The vine vigor, soil aggregation, and soil moisture benefits in plots with native cover crops were not expected to be seen so definitively in first years of establishment. With more time and investigation, other trends may become apparent, potentially making cover crop adoption more feasible and appealing to California farmers.
Funding Support: USDA-ARS
