Chairman's Report, 2017


Jason Bowen, Rice Research Board Chairman

Welcome to the 49th annual report to the California Rice Growers. In the following pages we report on grower funded research from 2017 that is essential to the California rice industry. This report tracks progress on rice breeding, genetic improvement, variety trials, weed and disease management, fertilizer research, invertebrate pest control, water use efficiency, environmental research, and studies examining rice straw utilization.

California’s public rice breeding program is conducted and managed by scientists at the Rice Experiment Station (RES). The program has made 49,043 crosses and released 47 improved public rice varieties since its inception in 1969. Foundation seed of 17 public varieties and basic seed of one Japanese premium quality variety were produced in 2017. Read about progress in the five major project areas in the Rice Breeding Program section.

Testing of promising experimental lines took place at 16 farm locations and at RES in 2017. Top-yielding advanced lines are reported for each of the three maturity classes, along with yields of standard varieties. Results of statewide testing are described in the Rice Variety Trials section.

Geneticists continued research to select genes associated with reduced uptake of arsenic and resistance or tolerance to the herbicide pendimethalin (Prowl®). This work is reported in Genetics for Rice Improvement.

Fertilizer research continued in four areas—potassium status of rice soils, management of rice under alternating flooded/dry conditions, rice yield variability, and improving fertilizer nitrogen use efficiency. Some highlights include: potassium fertilizer should be considered when soil potassium levels are below 120 ppm; alternative water management practices can reduce greenhouse emissions while not negatively affecting yields; medium grain yields have the potential to improve up to 1,500 pounds/acre; sensitivity to cool stress and heating stress during booting varies by grain type; and a handheld sensor is a promising tool to predict the need for a midseason top-dressed nitrogen application. Read about this work in Improving Fertilizer Guidelines for a Changing Rice Climate.

In a related project, research shows a strong link between nitrate assimilation and increased rice yields through nitrification of nitrogen fertilizer in the root zone. The magnitude of that influence varies among different cultivars. This work is reported in The Role of Nitrification in Rice Systems to Support Nitrogen Use Efficiency.

Evaluation of commercially available seaweed derived products marketed for rice production continued. Growers and PCAs who want to include these products should test them over several years at the desired locations to find the products that provide the most benefit. This research is reported in Evaluating Seaweed Extracts as Biostimulants in California.

Weed management research examined herbicide combinations for continuous flood, pinpoint flood, and drill-seeded rice. Significant research took place to optimize the newly available Butte® herbicide in combination with other herbicides. Other weed management research looked at new adjuvants, as well as different formulations and new active ingredients.  Preliminary results with an experimental line containing the Roxy™ trait that provides resistance to oxyfluorfen were very encouraging. Also, testing for suspected herbicide resistant weed populations increased. Read about this work in Weed Management in Rice.

An area of increasing concern is weedy red rice, which has been identified on more than 10,000 acres in every rice growing area except Sacramento County. Five distinct populations of weedy red rice have been identified. Precautions need to be taken to prevent further spread, including closely monitoring movement of rice seed and strict adherence to certified seed only usage. This research is reported in Weedy Red Rice Control.

A new project assessed the performance and feasibility of using remotely piloted aircraft to treat patches of weeds with herbicides. Results were consistently encouraging, demonstrating its potential for a new, flexible, and low cost method of controlling patchy weeds. Read about this research in Spot Spraying of Rice Weeds from Remotely Piloted Aircraft.

Rice diseases have long been a concern to growers. A renewed effort to enhance fungicidal control of diseases, particularly stem rot and aggregate sheath spot, began in 2017. This work, as well as an assessment of the threat posed by kernel smut, is reported in Rice Disease Research and Management.

The Rice Water Weevil (RWW) has been the subject of much research over the years. In 2017, eight active ingredients were examined in 16 ring plot treatments. Work also continued on the susceptibility of different rice varieties to RWW, control of tadpole shrimp, monitoring armyworms with pheromone traps, the impact of rice pesticides on nontarget insects, and evaluating the damage potential of several species of stink bugs. This work is reported in Protection of Rice from Invertebrate Pests.

Research on how rice pesticides degrade in the environment focused on the herbicide Butte® (benzobicyclon), the insecticide Coragen® (chlorantraniliprole), and modeling of the herbicide thiobencarb (Abolish® or Bolero®) leaving rice fields. Research on Butte® supports the 20-day water holding period recommended by the U.S. Environmental Protection Agency. Research on Coragen® indicates that it may mobilize with rice field tailwater. A model capable of predicting thiobencarb concentrations downstream from rice fields fits well with the Colusa Drain, but additional monitoring data would be necessary for the model’s application to other areas. Read about this research in Environmental Fate of Rice Pesticides.

Research wrapped up on the potential for rice herbicide drift to affect walnut growth and production. Studies were conducted with propanil (SuperWham!®), bensulfuron (Londax®), and bispyribac-sodium (Regiment®) at four rates resembling plausible drift. Although this research shows that bispyribac-sodium drift has the potential to be an issue for walnut orchards, it is unlikely that it would drift at high enough levels to cause significant yield and quality effects. Read about this work in Understanding the Effects of Rice Herbicide Drift on Walnuts.

A project to assess the presence of mercury in California rice systems continued. A study of alternate wetting and drying of rice fields showed that this technique reduced mercury concentrations in water, soil, and rice grains and could be used as a mitigation practice if necessary. A new area of research in this project is seeking to quantify methylmercury concentrations in commercial fields located in Butte, Colusa, and Yolo counties. This work is reported in Mercury in California Rice Systems.

Another project is examining arsenic uptake during rice cultivation. Research showed that alternate wetting and drying management has the potential to minimize both arsenic and cadmium simultaneously. Read about this research in the section Arsenic Speciation in Rice and the Environment.

Researchers are identifying opportunities to improve water use efficiency in California rice systems. Degree day models would be improved by using water temperatures during the first part of the growing season.  Other areas of research examined percolation and seepage losses, as well as water balance calculated for three sites. Read more in Identifying Opportunities for Improving Water Use Efficiency.

A project studying how to convert rice straw components into nanomaterials and advanced functional products is producing impressive results. A diverse array of nanocelluloses have been fabricated. Work continues on improving the processes and resulting products from this research. This work is reported in Novel Nanomaterials and Performance Industrial Products.

Researchers at California State University, Chico, shifted focus to a new area of research in 2017: anaerobic digestion of farm waste. Biogas production of rice straw was measured and compared with other farm based sources such as olives, apples, and peaches. Read about this work in Biobased Insulating Panels and Anaerobic Digestion of Farm Waste.

Another project at Chico State also shifted focus to investigate the use of rice straw ash in alkali-activated slag cement. Researchers report remarkable results in improving the physical properties of concrete with this innovation. This work is reported in Improving Concrete Properties with Rice Straw Ash.

Research also continues on the use of rice straw as a livestock feed. Cattle fed ammonia-treated rice straw as part of their diet substantially increased weight gain compared to other treatments. Read about this work in Increasing the Feeding Value of Rice Straw.

Our ongoing investment in research continues to reap many benefits for the California rice industry. We are a strong, reliable, economic engine of progress with a demonstrated commitment to environmental stewardship. That bodes well for the future of agriculture in our region. Wishing you all the best for a safe and productive year in rice country.