Rice Continued from Page 12
After Richter applied a preflood her- bicide and flooded the field, an air- plane flew on Calrose medium-grain rice variety M-521 and followed with a fertilizer application. Just four days after planting, a week of cold storms slowed the crop and forced Richter and his team of advisors to decide to reflood the field using drip to protect the seedlings. Eventually, the weather warmed and the farm was able to estab- lish the stand. Throughout the season, Richter walked the field and irrigated based on “eyeball- ing it.” The goal was to keep the root zone wet but not necessarily allow puddling on the soil surface. The team also fertigated, or applied liquid fertilizer through the drip tape. As the crop grew, Richter and his advi- sors noticed dark-green stripes in the field where high concentrations of fertilizer settled above the drip tape. As a result, they changed their irrigation tactics and applied more fresh water after fertigation to try to push the nutrients farther away from the drip lines. “We learned a lot about fertilizer move- ment and irrigation duration,” Richter said. In addition, the farm battled weeds, including cottonwood shoots and a lot of “strange” terrestrial species not found in conventional flooded rice fields. “You have a whole different spectrum
Drip-irrigation tape is applied to tubing on the edge of a Colusa County rice field. The farmer and researchers are studying different approaches to growing rice using less water and maintaining yields.
of weeds that grow in these different envi- ronments, and the chemicals work differ- ently,” Cook said. Deciding when to drain the field in prepa- ration for harvest also was an unknown. “When do you turn the water off? This is like nothing we’ve ever done before,” Richter said. He and advisors made an educated guess of two weeks before harvest, which in hindsight proved to be the right call. The crop dried down nicely, and there were no issues during harvest in late September. The field produced slightly more than 86 hundredweights per acre at
22.1% moisture, a yield Richter said he was pleased with. His conventionally grown rice fields yielded in the low 90 cwts. per acre. “Anything in the 70s would have been considered a success,” he said about the drip trial. His milling grades of 64/70, which denote the percentage of whole ker- nels compared to rice, were on the higher side. Overall, Richter said the trial penciled out because input costs were low. Compared to an adjacent rice field that was grown using traditional flooding, the trial used slightly more water overall. Richter said he and the research team
probably could have saved about 8 to 12 acre-inches had they not had to reflood the drip field during the cold snap. Based on lessons learned in 2023, Richter said they definitely plan to “crimp down on water use” this season. They also plan to try different approaches to herbi- cides and fertilizers. “The key is everything that goes into this has to be producing decent yields, produc- ing decent quality and needs to be more profitable than the alternative,” Richter said. (Vicky Boyd is a reporter in Modesto. She may be contacted at vlboyd@att.net.)
CIMIS REPORT | www.cimis.water.ca.gov
CALIFORNIA IRRIGATION MANAGEMENT INFORMATION SYSTEM
For the week of March 21 - March 27, 2024 ETO (INCHES/WEEK)
YEAR
3.0
THIS YEAR
2.5
LAST YEAR AVERAGE YEAR
2.0
1.5
1.0
0.5
0.0
MACDOEL II (236)
BIGGS (244)
DAVIS (06)
MANTECA (70)
FRESNO (80)
SALINAS-SOUTH (214)
FIVE POINTS (2)
SHAFTER (5)
IMPERIAL (87)
THIS YEAR LAST YEAR AVG. YEAR % FROM AVG.
0.72 0.58 0.76 -1
0.73 0.82 0.87 -17
0.73 0.80 0.96 -23
0.63 0.84 0.90 -30
0.92 0.89 0.95 -4
0.89 0.94 0.92 -3
1.00 0.88 1.08 -6
0.94 0.81 1.01 -5
1.59 1.38 1.45 10
W eekly reference evapotranspiration (ETo) is the rate of water use (evapotranspiration—the sum of soil evaporation and crop transpiration) for healthy pasture grass. Multiplying ETo by the appropriate crop coefficient gives estimates of the ET for other crops. For example, assume ETo on June 15 is 0.267 inches and the crop coefficient for corn on that day is 1.1. Multiplying ETo by the coefficient (0.26 inches x 1.1) results in a corn ET of 0.29 inches. This information is
useful in determining the amount and timing of irrigation water. Contact Richard Snyder at the University of California, Davis, for information on coefficients, 530-752-4628. The 10 graphs provide weekly ETo rates for selected areas for average year, last year and this year. ETo information is provided by the California Irrigation Man- agement Information System (CIMIS) of the California Department of Water Resources.
For information contact the DWR district office or DWR state headquarters:
SACRAMENTO HEADQUARTERS: 916-651-9679 • 916-651-7218
NORTHERN REGION: Red Bluff 530-529-7301
NORTH CENTRAL REGION: West Sacramento 916-376-9630
SOUTH CENTRAL REGION:
SOUTHERN REGION:
Fresno 559-230-3334
Glendale 818-500-1645 x247 or x243
April 3, 2024 Ag Alert 13
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