Chairman's Report, 2020

 

Andrew Rudd, Rice Research Board Chairman

Welcome to the 52nd annual report to the California Rice Growers.  In the following pages, we report on grower funded research from 2020 that is essential to the California rice industry. This report details progress on rice breeding, genetic improvement, variety trials, weed and disease management, fertilizer guidelines, invertebrate pest control and insect monitoring, water use efficiency, environmental concerns, new work on crop rotations, and several studies examining rice byproduct utilization.

California’s public rice breeding program is conducted and managed by scientists at the Rice Experiment Station (RES). The program has made 52,416 crosses and released 51 improved public rice varieties in 11 different market classes since 1969. Just over 500 entries were evaluated in advanced yield tests and 687 entries in the preliminary yield tests in 2020. Read about the intensive work involved for new variety development in the Rice Breeding Program section.

Testing of promising experimental lines takes place at representative farm locations and at the RES. Top-yielding advanced lines are reported, along with yields of standard varieties. Testing advanced and preliminary lines under a variety of conditions is a critical aspect of new variety development. Results of this testing are described in the Rice Variety Trials section.  

One of the main areas of current focus for genetics research is screening three advanced mutant populations associated with with reduced uptake of arsenic in rice. Evaluation of herbicide tolerance is another area and was planned for early 2021. The timetable for work on this project was delayed in 2020 by restricted access to research facilities caused by the pandemic. This work is reported in Genetics for Rice Improvement.

A project examining ways to treat rice seeds to improve early plant growth entered its second year. The process involves low-frequency vibration of the water used for seed soaking. Greenhouse and field trials were conducted last year. This approach could lead to multiple advantages in the rice crop. Read about this promising research in Treatment of Rice Seeds for Early Growth.

Fertilizer research in 2020 focused on three primary areas: assessing nitrogen need through remote sensing; early season nitrogen losses caused by the action of flooding and draining; and developing alternative fertilizer management strategies. Remote sensing is proving its usefulness. In one experiment a top-dressed nitrogen application increased yields between 200 and 1,000 pounds/acre. Two years of studying early season nitrogen loss through denitrification and as nitrous oxide has shown that 20 to 30 pounds/acre of fertilizer nitrogen can be lost through drainage events. A study at the Rice Experiment Station examined different sources and timing of nitrogen applications. Split applications produced the highest yields. This work, as well as other experiments on lodging and planting dates, are reported in Improving Fertilizer Guidelines for California’s Changing Rice Climate.

Weed management research focuses on new and existing herbicides, alternative crop establishment methods, and herbicide resistance strategies. Several herbicide combinations provided good to excellent control of target weeds. Special areas of focus included Cerano® rate and timing and optimizing Loyant® programs. Nine separate studies in 2020 evaluated different formulations and new active ingredients in continuously flooded rice systems. Herbicide resistance in different weed species is summarized in a table generated from 2019 screening. This work is reported in Weed Management in Rice.

Scientists have been working with the industry since 2016 on weedy rice. In 2020, six out of 31 samples were confirmed to be weedy rice, including three new sites in Sutter, Yuba, and San Joaquin counties. Several seed fields were found to be contaminated with weedy rice. How weedy rice spreads is not known, although shared equipment is strongly suspected. Results of a field trial and an overwintering experiment also are reported in Weedy Rice Control.

Loyant® is a promising new herbicide for California rice. In 2020, research evaluated its potential risks for off-target crops, particularly trees and vines. Pistachio was found to be more sensitive to the herbicide than other crops such as grapes, prune, peach, almond, and walnut. This simulated herbicide drift study provided useful information for developing integrated stewardship plans for rice adjacent to perennial crops. Read about this work in Stewarding a New Herbicide for California Rice.

A number of new weed species have been identified in the last several years. The range of some of these species is unknown. Results of a comprehensive soil survey conducted in the fall of 2019 are reported and summarized in a table of identified weeds by county. Preliminary analyses show that redstem and smallflower umbrella sedge were the only two weed species found across all sites and in all counties. Additional research confirms what growers have been observing—watergrass has been escaping early season control efforts and becoming very difficult to control later in the season. Learn more in Emerging Weed Issues in Rice.

Rice diseases of concern to the California rice industry include aggregate sheath spot, stem rot, and kernel smut. In 2020, 11 fungicide trials were conducted at several locations throughout the Sacramento Valley. In general, results continue to show that reduction in stem rot, aggregate sheath spot, or blast incidence and severity can be achieved with applications at mid-boot stage. Additional work focused on testing methods to rate kernel smut damage and assess kernel smut damage to different rice varieties. CH-202 had the lowest kernel smut levels compared to other varieties. This work is reported in Rice Disease Research and Management.

Although rice water weevil (RWW) has been in California for more than 60 years, populations have been declining and they are no longer considered a key pest. Nonetheless, work continues on RWW control. Data from insecticides used in recent years show that Warrior® and Belay® are effective. Dimilin® showed mixed efficacy, while an organic product, Venerate®, showed minimal efficacy. Tadpole shrimp are crustaceans that have been a problem in California rice fields since the 1940s. A number of different products were tested in metal ring plots. Researchers report some interesting results, with Dimilin® and Belay® proving to be effective alternatives where tadpole shrimp may be developing resistance to pyrethroids. Armyworms have become an increasing concern, so use of pheromone traps to improve detection has expanded in recent years.  One trial confirmed that Intrepid® and Prevathon® can provide good control of armyworms in rice. Work also continued on a simulated defoliation study that showed the significant potential impacts to plant height, panicle weight, and yield from armyworms. This, and related research, is reported in Protection of Rice from Invertebrate Pests.

A new project is looking into the advantages and disadvantages of crop rotations in California rice systems. One big advantage in which many surveyed growers agree upon is the potential for better weed control and reduced reliance on herbicides. And there are other potential advantages to consider, including economics, soil health and types of rotations. Read about those in Crop Rotations in California Rice Systems.

A somewhat related study is examining water use by non-irrigated cover crops grown in rotation with rice. Four fields in Yolo County were measured to quantify differences in evapotranspiration rates between a fallow field and three fields under different non-irrigated cover crops. Learn about preliminary results from this work in Quantifying Water Use of Cover Crops in Rotation with Rice.

Water use is always a top of mind concern for farmers, especially during drought. Attention in an ongoing study of water use is now focused on how land use changes in the Sacramento Valley are linked to water and what that could mean for the future of the rice industry. Research in 2020 documented an increase in perennial crops in some traditional rice fields; the dynamics of leaving fields fallow in response to drought; and the extent of rotation into other field crops in the southern Sacramento Valley. Read more in Identifying Opportunities for Improving Water Use Efficiency.

Engineers continued making refinements to a real-time insect monitoring and detection system for use in rice storage facilities. Research in 2020 focused on testing and demonstrating a scaled-up system at the Sutter Basin Growers Cooperative in Knights Landing. Results were very positive, but testing at other storage locations is needed, as well as research on the quality and economic benefits of this new technology. Read about this research project in Insect Monitoring and Early Detection System in Rice Storage Facilities.

An ongoing project studying the conversion of rice straw components into nanomaterials and advanced functional products has produced impressive results that are gaining the interest of industry in some novel applications. This work is reported in Novel Nanomaterials and Performance Industrial Products.

A project at Chico State focused its research in 2020 on utilizing rice straw cellulose in automotive interior parts. A prototypical mix with rice straw, almond shells, and recycled plastic was sent to Michigan for further development and examination by Ford Motor Company. The rice straw mixture should make for a superior interior auto part. Read about this research in Automotive Headliner made from Rice Straw and Recycled Plastic.

Rice-based ashes have potential for use in concrete to fill a growing need in the construction industry and to help meet carbon emission reduction requirements. Research in 2020 focused on improving the consistency and increasing the reactivity of rice hull ash produced in conventional bioenergy systems. Analysis is continuing on understanding the influence of various treatment methods. Read more about this work in Treatments to Improve Properties of Rice Ash in Concrete.       

In spite of a year full of challenges for everyone, I’m happy to report that we are making good progress in the various research projects funded by the rice industry. And none of it happens without the ongoing support of California growers through the Rice Research Board. Thank you. Wishing you all the best for another safe and productive year in rice country.

—Andrew Rudd, chairman