Bruce Linquist: Distinguished Rice Research and Education Award

Plant Sciences faculty member and Cooperative Extension specialist Bruce Linquist received the Distinguished Rice Research and Education Award from the Rice Technical Working Group at their annual conference last month in Long Beach, California. Linquist chaired the conference.

Bruce Linquist, Department of Plant Sciences at UC Davis, and UC Cooperative Extension/UC ANR.

Linquist has been collaborating with rice researchers in the southern U.S., and he is the only California recipient of the award. Other team members are from the University of Arkansas, the USDA (Jonesborough, Arkansas), and Louisiana State University.

Details of the award are summarized below.

Advancing irrigation management practices to achieve sustainable intensification outcomes

Team members: Merle Anders, Michelle Reba, Benjamin Runkle, Chris Henry, Joe Massey, Jarrod Hardke, Arlene Adviento-Borbe, Bruce Linquist, Steve Linscombe, Dustin Harrell

Until recently, the only way most farmers thought of growing rice was by maintaining the field constantly flooded. This practice is easy to manage and has many advantages including good weed control, reduced blast, and efficient use of N fertilizer, which lead to the high yields possible in most of the rice growing states within the U.S. However, maintaining a constant flood also has drawbacks. These drawbacks include high water use, high methane emissions, and increased availability of some heavy metals that can result in high concentrations in rice grains relative to other cereal crops. Introducing aerobic periods during the growing season (often referred to as alternate wetting and drying or AWD) has been shown to reduce CH4 emissions and water use in Asia; however, this was usually accompanied by yield loss.

This team, with members crossing disciplinary boundaries and geographic regions, and including those with both research and extension appointments began research in 2010 on AWD. Results from numerous field trials indicate that with AWD, rice yields can be maintained or more efficiently grown while also reducing water use by up to 30%, CH4 emissions by 50 to 90% with minimal increases in N2O, and As and MeHg grain concentrations by over 50%, relative to continuous flooding. These are achieved with no changes to N fertilizer or weed management. Using the right varieties, there is no increase in blast. These benefits are all well documented in numerous publications. Members of this team have pushed the bar even further by growing rice under completely aerobic conditions (referred to as furrow irrigated rice or row rice) which has all of the above mentioned benefits but can reduce water use even more.

While these practices were tested on small plots, adoption at the field level possess additional challenges. First, many growers are uncomfortable growing rice in anything but a flooded field. Second, fields are often large and heterogeneous. Researchers developed irrigation practices that allow the fields to be reflooded quicker and more uniformly using polytubing. These findings, along with extension efforts by university personnel and partnerships with the USDA-NRCS Rice Stewardship Program have fostered adoption of these practices. In 2017, over 150,000 acres were enrolled in the NRCS RCPP-Ducks Unlimited program that featured AWD flood management.

Apart from the interest these practices have generated among rice growers, this research has attracted the interest of a number of organizations. For example, the USA Rice Sustainability Committee has used information generated by this research extensively in promoting sustainable production practices. The White River Irrigation District, through multiple Conservation Innovation Grants has been able to promote this practice within their district. In addition, these practices have also caught the attention of private companies such as Mars Inc., Walmart, Unilever and Kellogg’s that are interested in promoting sustainable rice production practices. RiceTec also includes AWD practices under their guidelines to help growers maximize sustainability efforts through their “Smart Rice” program.

The American Carbon Registry also developed a protocol – “Voluntary Emission Reductions in Rice Management Systems” which allows growers to receive carbon credits for various management practices including AWD as it leads to reductions in CH4 emissions. In 2017 this program was officially completed and seven farmers from California, Arkansas and Mississippi participated – generating the first ever carbon credits from rice which were sold to Microsoft.

Recently, Field to Market: The Alliance for Sustainable Agriculture partnered with team members to improve the Rice Fieldprint platform which allows producers to benchmark their farms sustainability performance. Using US data, GHG emissions and major factors controlling GHG emissions were quantified, allowing Field to Market to develop a tool that will allow producers to evaluate the carbon footprint of rice at a field scale based on soil, variety and field management practices – including AWD water management.

The adoption of these irrigation management practices by rice producers across all of the southern rice producing states is remarkable given the complexity of these changes at the farm level and is a true testament to the quality of research from this team and the extension efforts made.

(Article by Ann Filmer, Dept. of Plant Sciences, UC Davis)

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