Developing and Promoting Intercropping in California’s Perennial and Annual Agroecosystems

Commodities

• Agronomic: flax, peas (field, cowpeas), safflower, soybeans
• Nuts: almonds, walnuts
• Vegetables: broccoli, cabbages, greens (leafy), greens (lettuces)

Practices

• Crop Production: alley cropping, cropping systems, intercropping
• Education and Training: demonstration, display, on-farm/ranch research, youth education
• Farm Business Management: budgets/cost and returns, feasibility study
• Production Systems: agroecosystems
• Soil Management: soil analysis
• Sustainable Communities: new business opportunities

California’s agroecosystems are among the most diverse cropping systems in the world. However, lack of crop diversity within individual farms and regions has negatively impacted agricultural sustainability and environmental quality. For example, recent price reduction of nuts financially hurts growers who have planted over 2 million acres of monoculture walnuts and almonds across California. Similarly, intensive tillage and fertilizer application in vegetable systems has led to groundwater contamination, resulted in increased regulations, such as the "Ag. Order 4.0," which mandates soil nitrogen monitoring. This project will explore the potentials of intercropping in California's orchards and vegetable crops to improve soil health and environmental quality, and enhance and diversify growers income. The project will include the following components: 

Field Trials

1.Alley Cropping:

Alley cropping is growing annual cash crops in the alleyways between orchard trees. Lack of knowledge about alley cropping and concerns about its potential negative impacts on long-term life and productivity of trees limit its adoption in California. We will investigate the agronomic feasibility, challenges, and costs and benefits of growing various annual crops between young orchards, and monitor orchard trees overall growth and health. The goal is to promote alley cropping as a sustainable farming practice that can enhance and diversify growers income. 

2.Intercropped Vegetables - Fiber Flax:

Fiber flax is a cool season crop, planted in the fall in northern California. Flax is planted in a high density (6" row spacing) and provides effective ground-cover that can reduces weed pressure and protects soil from erosion during rain events. We will study the effects of intercropped fiber flax with cool-season vegetables to reduce weed pressure and provide ground cover during rain events. Both flax and vegetables will be harvested, and their yield, cost of planting, harvesting, processing, and their market values will be quantified. Weed pressure and runoff during rain events will be recorded. 

A comprehensive cost-benefit analysis will be performed to assess the economic sustainability of these practices.

Educational and Outreach Programs

1.Field Day Demonstrations:

We will host field day events to demonstrate the intercropping systems to growers. Attendees will receive educational materials about the technical aspects of intercropping and cost-benefit analysis data to support informed decision making. Educational materials will become available through our website and other online platforms.  

2. Demonstration Plots

We will establish demonstration plots at the NRCS Plant Material Canter to showcase intercropping practices to growers and industry representatives during PMC field day events.

3.Agriculture Education for Grades 6–12:

In collaboration with the California Agriculture Teachers’ Association, we will develop educational lessons tailored to students in grades 6–12. These lessons will focus on sustainable agriculture practices, especially intercropping and soil health. By engaging students, we aim to inspire the next generation of agricultural professionals and raise awareness of the importance of agricultural sustainability.

4.Scientific Community Engagement:

The outcomes of research and educational program will be shared with the scientific community through presentations at the American Society of Agronomy (ASA) and California Plant Science conferences. We anticipate publishing at least one peer-reviewed journal article. 

Research Objectives:

• Quantify the performance, yield, and quality of field and vegetable crops grown between tree rows in orchards.
• Assess the costs and economic returns of alley cropping systems in northern California.
• Evaluate the yield and quality of intercropped vegetables and fiber flax.
• Measure runoff, soil infiltration, and soil organic matter in response to alley cropping and intercropping.

Educational Objectives:

• Conduct field day demonstrations for growers, industry professionals, and local communities.
• Develop educational materials for growers, agricultural educators, and students in grades 6-12.