Facilitating Integrated Weed Management in California Rice: Predicting E. spp. and C. difformis emergence across heterogeneous growing environments

View the project final report

• 2011 annual report
• 2012 annual report

Commodities

• Agronomic: rice

Practices

• Crop Production: conservation tillage
• Education and Training: decision support system, extension, on-farm/ranch research, workshop
• Farm Business Management: risk management
• Pest Management: cultural control, genetic resistance, precision herbicide use, weather monitoring, weed ecology
• Production Systems: agroecosystems

Herbicide resistant weeds are an ever-worsening problem in California rice systems. By integrating cultural and chemical control of weeds, alternative stand establishment approaches have been shown to reduce herbicide resistant weed populations while simultaneously reducing herbicide inputs in direct seeded rice. However, management decisions are both more numerous and more complicated when growers use alternative establishment methods for weed control. The overarching goal of the proposed research is to develop a geographically- and temporally-sensitive decision support tool that predicts the minimum time required to achieve control of Echinochloa spp. and Cyperus difformis populations using alternative establishment management methods in direct-seeded rice. Coupled with effective outreach, this tool will facilitate the planning and execution of weed control via management and enable wider adoption of alternative establishment approaches.

Objective 1: Produce an empirical model that predicts the emergence of E. spp. and C. difformis as a function of air temperature, solar radiation, water depth and irrigation timing.

Objective 2: Determine the spatial and temporal resolution at which air temperature and solar radiation can be predicted across the Sacramento Valley between April 15 and June 1, based on available historical data.

Objective 3: Confirm the accuracy of spatio-temporal interpolations of air temperature and solar radiation via in-field temperature and light measurements that span the Sacramento Valley.

Objective 4: Validate the accuracy of the model's emergence predictions across heterogeneous spatial and temporal environments.

Objective 5: Implement a web-based tool that communicates spatially- and temporally-sensitive emergence predictions to growers.

Objective 6: Communicate management-related results of research to growers via UC extension networks, field days, production workshops and grower meetings, as well as through UC websites and publications.

Objective 7: Publish a peer-reviewed scientific paper that reports on the accuracy and efficacy of a spatio-temporally sensitive weed emergence model for stale-seedbed, direct-seeded rice. A manuscript will be submitted for publication by the end of 2012.