- Author: Michelle Leinfelder-Miles
In 2022, I estimate rice acreage in the Delta, south of the Yolo Bypass, was at least 8,000 acres. Most Delta rice is grown in San Joaquin County, but there is some acreage in Sacramento County. While Delta rice acreage is relatively small compared to that in the Sacramento Valley, it has been steadily increasing over the last several years (Table 1).
Table 1. Rice acreage and yield according to the San Joaquin County Agricultural Commissioner's crop reports. County rice production is predominantly in the Delta region.
Given the increasing interest in rice production among Delta growers, and the differences in production practices from the Sacramento Valley, UC Cooperative Extension and UC Davis will be releasing a cost of production report specifically for Delta rice later this year or in early 2023. A Delta rice cost study was last produced in 2007, so updating the study was long-overdue. I want to thank all the growers who participated in a focus group to update the study.
Cool temperatures can make the Delta a challenging place to grow rice. Low night-time temperatures can cause blanking, which results in empty grains. Growers are limited to using only very-early and early maturing varieties. Most of the Delta acreage was planted with variety M-206, but some growers also planted a portion of their acreage with M-105. In 2022, we continued the UCCE Delta variety trial, which will help to identify and advance cold-tolerant varieties. The Delta trial is part of a statewide network of trials, led by UC Rice Extension Specialist, Bruce Linquist, and coordinated by Staff Researcher, Ray Stogsdill. I anticipate that the statewide results will be ready in early 2023.
This year, I worked with growers and consultants on a handful of pests. Weed management is always top-of-mind for rice growers. There are limited practices and products that can control problematic weeds, and in some circumstances, the weeds may develop resistance to the herbicides that are available. If herbicide resistance is suspected, please contact me so that we can submit weed seeds for testing. We would collect the seeds in the late summer or early fall when they have matured but have not shattered. Resistance testing is overseen by UC Weed Science Extension Specialist, Kassim Al-Khatib, and takes place in greenhouses during the winter. By the following spring, we provide the grower with information on which herbicides are still working and which are not.
I have been trapping armyworms in the Delta since 2016, in collaboration with fellow farm advisor, Luis Espino. The traps catch true armyworm moths. They were deployed on three ranches and monitored weekly. In 2022, we recovered the highest moth counts since 2017, and the peak flight occurred about one week earlier than in 2017. This is important information for management because, based on the armyworm life cycle, we know that peak worm populations occur approximately two weeks after peak moth flight. In other words, growers can make informed decisions based on the monitoring data and adapt their management to the field conditions. Trap monitoring is one part of an integrated pest management program for armyworms, which also includes scouting for feeding damage and the worms themselves. Over the years, I have observed armyworms in riparian and wetland vegetation that neighbor rice fields, so it is important to scout those areas, too.
We should continue to keep weedy rice on our radars because we have seen it in the Delta in the past. Where we have observed light infestations, it appears that keen management – including in-season rogueing, post-harvest management that includes straw chopping but not incorporation, and winter flooding – can reduce, if not eliminate the pest. These are our management tools until a herbicide is approved for spot-spraying. Growers should also pay attention to equipment sanitation – harvesting weedy rice fields last (if possible) and thoroughly cleaning out equipment after harvesting fields where weedy rice has been observed.
Finally, I will be starting new projects this winter, in collaboration with fellow farm advisor, Whitney Brim-DeForest, and graduate student, Sara Rosenberg, to evaluate winter cover cropping between rice crops. Our objectives are to evaluate carbon and nitrogen cycling and variety survivability during the cool, wet (we hope!) winter conditions. These projects are supported by the CDFA Healthy Soils Program and the CA Rice Research Board. I look forward to sharing results in the years to come.
I am grateful to work with a great team of UC colleagues on these rice projects. I am also grateful for all the growers who have collaborated with us. I wish everyone a good end to the year, and I look forward to working with you again in 2023.
- Author: Michelle Leinfelder-Miles
- Author: Mark Lundy
The Delta trial was on a Gazwell mucky clay soil, which has approximately 10 percent organic matter in the top two feet of soil. Approximately 25,000 acres in the Delta have the Gazwell classification. The 2021-22 season was characterized as being very wet from October through December, followed by very dry starting in January. An atmospheric river event dropped over six inches of rain at the end of October, according to a nearby CIMIS weather station, which delayed trial planting until December 1st. Over the course of the season, the site received approximately 10 inches of rain, and the site was not otherwise irrigated. The previous crop in the field was corn, and a pre-plant soil nitrate quick test indicated adequate nitrogen fertility at planting. The field received approximately 140 lb N/ac with in-season applications.
Under the 2021-22 conditions, the top-yielding wheat varieties (Table 1) in the Delta were UC 1961 (4.1 tons/ac; 11.2% protein), WB 9725 (4.0 tons/ac; 11.9% protein), and WB 9990 (3.8 tons/ac; 12.2% protein), and the top-yielding triticale varieties (Table 2) were UC Atrea (4.2 tons/ac; 10.6% protein), APB T470308 (4.1 tons/ac; 11.0% protein), and UC Bopak (3.9 tons/ac; 11.4% protein). The barley varieties were preferentially damaged by birds, and yields were impacted. Of what was left to be harvested, the top-yielding barley varieties (Table 3) were UC 960 (2.8 tons/ac; 8.0% protein), UC 933 (2.5 tons/ac; 8.9% protein), and Ishi (2.2 tons/ac; 7.4% protein). Please see the website for complete results.
Since environmental conditions vary from location to location and year to year, we advise making variety decisions based on aggregated data from three-year summaries. The results for the Delta best align with those from the Sacramento Valley. Thus, the Delta results are incorporated into the three-year summaries for the Sacramento Valley. The UC Davis team has developed web tools that allow us to view trial data in a more interactive way. There are two websites – one with the multi-year, multi-site summary data and another that summarizes each trial individually. We recommend using the multi-year, multi-site tool for variety decision making, and we suggest using these interactive tools on a computer, rather than a phone. Please reach out if you have questions on the trials or the web tools. Happy harvest, and good luck with your small grains crops this season!
Table 1. Delta common wheat trial results.
Table 2. Delta triticale trial results.
Table 3. Delta barley trial results. This trial had severe bird damage, and results shown are only for those varieties with sufficient yield to harvest.
- Author: Michelle Leinfelder-Miles
In 2022, the Sacramento-San Joaquin Delta Conservancy, in partnership with the Department of Water Resources and the Office of the Delta Watermaster, launched the Delta Drought Response Pilot Program (DDRPP). The purpose of the program was to conserve water and protect water quality, in light of continued drought. Growers who participated in the program were provided with a grant to implement water-saving practices, like deficit irrigation or planting a non-irrigated cover crop. In 2022, over 8,700 acres in the Delta were enrolled in the program.
The DDRPP will be offered again in 2023, and there are opportunities this week to learn more about the program. A virtual workshop will take place Thursday, October 6th from 10am to noon. Registration is required for the virtual workshop. Additionally, two in-person workshops will take place on Friday, October 7th. A north Delta meeting will take place at the Jean Harvie Community Center from 10am to noon, and a south Delta meeting will take place at the Roberts Union Farm Center from 2-4pm. For the in-person workshops, registration is encouraged but not required. If you are interested in the 2023 DDRPP, I encourage you to visit the Delta Conservancy website and participate in a workshop this week.
In addition to the 2023 grant program, we will also begin a research project. I will be collaborating with project leaders Kosana Suvocarev and Kyaw Tha Paw U from UC Davis to measure evapotranspiration and calculate water budgets over the next three years. To do this, we will set up equipment in six enrolled fields and monitor evapotranspiration, CO2 exchange, soil moisture, precipitation, among other properties. We will also evaluate crop consumptive use remote sensing applications for these Delta locations. As part of the 2023 DDRPP application, growers can elect to participate in this research project. If you have any questions about the research project or its objectives, please don't hesitate to contact me.
- Author: Michelle Leinfelder-Miles
The UC Alfalfa and Forage Field Day will take place on Thursday, September 29, 2022. The field day will take place at the Kearney Research and Extension Center, 9240 S. Riverbend Ave., Parlier, CA 93648. Sign-in and morning refreshments begin at 7:00am, and the field tour tram leaves promptly at 8:00am. There is no registration fee, but please pre-register for the event to help us with our planning. Only preregistered attendees are guaranteed a lunch. We have applied for DPR, CCA, and N management (ILRP program) continuing education credits, and the agenda is below. We look forward to seeing you at the field day!
Agenda:
7:00 AM Sign-in and morning refreshment
8:00 TRAM LEAVES FOR FIELD TOUR
- Choosing Alfalfa Varieties for Pest Management and Adjustments to Water Situations – Dan Putnam, UC Davis
- Sorghum Drought Research – Bob Hutmacher, UC West Side Research and Extension Center
- Sorghum Varieties – Bob Hutmacher, UC West Side Research and Extension Center
- Winter Flooding and Summer Deficit Irrigation of Alfalfa – Khaled Bali, UC Kearney Research and Extension Center
- Compost Trials in Alfalfa – Michelle Leinfelder-Miles, UCCE San Joaquin
10:00 TRAM RETURNS
10:10 Alfalfa Weevil Resistance Management – Ian Grettenberger, UC Davis
10:25 Pesticide Regulations – Drift Prevention and New Laws – Shawn Atayasay, Fresno County Ag Commissioner's Office
10:40 ALS Herbicide Resistance Screening of Common Chickweed in Small Grains – Nick Clark, UCCE Kings
10:55 Discussion
11:10 Break
11:20 Introduction of UC Cooperative Extension Specialist for Abiotic Stress – Jackie Atim, UC Merced
11:35 Small Grains Drought Resiliency – Mark Lundy, UC Davis
11:50 Alfalfa Cutting Schedule Impacts Yields, Quality, and Weeds – Dan Putnam, UC Davis
12:05 Discussion
12:20 Lunch
- Author: Michelle Leinfelder-Miles
- Author: Rachael Long
- Author: Radomir Schmidt
Since Fall 2020, I have been evaluating the effects of applying green waste compost on established alfalfa. The three-year project includes two trials – one in the San Joaquin County Delta and the other in Yolo County – and is a collaboration with Rachael Long (UCCE) and Radomir Schmidt (UC Davis). The project is supported by a CA Department of Food and Agriculture Healthy Soils Program (CDFA HSP) demonstration grant. Our interests are in evaluating whether compost enhances soil carbon and nitrogen storage, improves soil physical characteristics (i.e. improved water infiltration, reduced compaction), reduces greenhouse gas emissions, and/or boosts alfalfa yield.
Compost is decomposed organic matter from plants or animals and may be classified by the carbon-to-nitrogen ratio (C:N). The C:N is the relative amount of carbon and nitrogen in the material. Plant-derived composts (like green waste compost) have a high C:N, and animal-derived composts (like composted manures) have a low C:N. A material with a ratio greater than 30:1 is considered a high C:N material. The ratio is important because it affects microbial metabolic functioning and plant-available nitrogen. Both high and low C:N composts promote soil functioning by increasing soil carbon that is in a form easily accessible to microbes. That, in turn, can improve soil biological activity and physical conditions. With a high C:N material, however, nitrogen may be immobilized (“tied up”), so soil nutrient monitoring is important in order to stave off impacts to crops.
The San Joaquin County trial is approximately 20 acres, and there is no history of compost application at the site. The soil is a Peltier mucky clay loam that is considered partially to poorly drained. Compost applications are surface-applied in the fall/winter to plots that are two border checks wide (120 ft) and approximately 1000 ft long. Two green waste compost rates – 3 tons/ac and 6 tons/ac – are being compared to the untreated (non-composted) control. The first compost application was made in Fall 2020 following the first cutting season of the alfalfa stand. The second application was made in Winter 2021, and the final will occur in fall/winter 2022. Baseline soil samples were collected at the beginning of the study (October 2020), and annual sampling is done every fall season before compost application. Alfalfa yield is assessed 3-4 times per year by taking quadrat samples from the grower's windrows. Greenhouse gas samples are collected on a monthly basis.
Preliminary results. Yield was measured from three cuttings in 2021, and so far, from two cuttings in 2022. (We anticipate measuring yield from two more cuttings in 2022.) Our preliminary results from these five cuttings indicate that compost can improve alfalfa yield over the untreated control but that a rate of 6 tons/ac does not improve yield over the 3 tons/ac rate (Fig. 1). We are also testing forage quality, and those results will be available in the fall.
I recently held a field day at the trial location. If you were not able to make it, please visit my website for the handouts. The handout “Compost for Soil Improvement in Alfalfa” shows other preliminary results from this trial, including soil carbon and nitrogen and greenhouse gas emissions. In addition, there are handouts describing other organic matter amendments in alfalfa and forages.
Figure 1. Preliminary yield results over five cuttings in 2021 and 2022. The compost rate of 3 tons/ac improved alfalfa yield over the untreated control.
Conclusions. Organic matter amendments, as from compost, can improve soil functioning, but changes take time to observe, let alone be realized financially. We estimate that compost (material plus hauling) costs approximately $27/ton, with an additional $10/ton for spreading (Fig. 2). To help offset the costs, the CDFA HSP provides incentives grants for farmers, and more funding may be available later this year. UC ANR Technical Service Providers Hope Zabronsky or Caddie Bergren are available to help growers with the application. And please don't hesitate to reach out to me if you would like more information on this trial or on the CDFA incentives programs.
Figure 2. Compost spreading at the San Joaquin County trial. Compost is not a small expense, but it may help improve soil functioning and alfalfa yield over the long-term.