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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #398204
Research Project: Strategies to Improve Soil and Pest Management in Organic Vegetable and Strawberry Production Systems

Location: Crop Improvement and Protection Research

Title: Predicting cereal cover crop biomass using shoot length in California vegetable systems

Author
item Brennan, Eric
item SMITH, RICHARD - University Of California - Cooperative Extension Service

Submitted to: Agricultural & Environmental Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2022
Publication Date: 1/15/2023
Citation: Brennan, E.B., Smith, R.F. 2023. Predicting cereal cover crop biomass using shoot length in California vegetable systems. Agricultural & Environmental Letters. 8(1). Article e20099. https://doi.org/10.1002/ael2.20099.
DOI: https://doi.org/10.1002/ael2.20099

Interpretive Summary: Farmers need simple and reliable methods to know how much biomass their cover crops have produced. This information can help them understand how much carbon the cover crop is adding to the soil. In the central coast of California this information can also help farmers receive a cover crop nitrogen scavenging credit due to a new regulation known as Ag Order 4.0. This credit will help farmers to meet the regulatory limits on nitrogen inputs from fertilizers. To address this need for a farmer-friendly biomass estimation method, data were collected on cover crop biomass and shoot length of Merced rye and Pacheco triticale cover crops growing in over 20 fields on vegetable farms in the California Central Coast region and from five research station trials in the Salinas Valley. This research showed that shoot height, determined with a measuring tape, is a time-efficient way for farmers to estimate cover crop shoot biomass. This has immediate practical application to over 500,000 acres of irrigated land in the central coast of California.

Technical Abstract: To better understand cover crop benefits and receive nitrogen scavenging credits for cover cropping, farmers need simple and robust methods of predicting cover crop biomass production. A new regulation focused on improving nitrogen management on over 200,000 ha of irrigated land in the central coast of California motivated us to evaluate if the shoot length of rye (Secale cereale L., ‘cv. Merced’) and triticale (X Triticosecale Wittmack, cv. ‘Pacheco’) could predict shoot biomass. Field samples for rye (n=162) and triticale (n=126) were collected at various developmental growth stages from organic and conventional vegetable farms and planting date trials, across multiple soil types, planting times, row spacings, and plant densities. Main shoot length was well-correlated with oven-dry shoot biomass for rye (r=0.87) and triticale (r=0.88). This provides farms in California and beyond with a simple, robust method to estimate cover crop shoot biomass.