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Oilseeds News & Updates

Spring Canola Nitrogen Rate Calculator Release

The N rate calculator uses estimated yield and soil N supply to determine the amount of N fertilizer required. The estimated yield is used to determine the total amount of N required to achieve a particular yield goal. The soil N supply is determined using the soil organic matter content, the soil mineral N amount from a soil test, and the proceeding crop. The proceeding crop can serve as a N debit that removes N from the system or a N credit that adds to the total supply. Legumes serve as a credit, whereas winter wheat serves as a debit. The soil organic matter content and tillage method are used to calculate N mineralization. Nitrogen mineralization is the process during which soil organic matter is converted to plant-available N. Mineralization depends on the microbes present in the soil and varies depending on soil moisture and temperature. The soil mineral N is the total plant-available nitrogen in the forms of nitrate and ammonium in the soil at the time of the soil test.

How Deep is Too Deep to Plant Winter Canola?

Winter canola establishment has always been a challenge in Washington. Canola prefers to be seeded shallow (0.5-1.5”) and in good moisture. The dry summers of the inland Pacific Northwest that cause moisture to recede deeper into the soil profile can lead to poor germination and emergence. One strategy for improving stand establishment is to target early seeding dates. However, early seeding dates can increase the susceptibility of the canola to fall drought and winter kill. When considering later seeding dates, the challenge is to put the canola seed into moisture without going too deep.

Soil Science Alumnus Isaac Madsen Chosen to Lead WSU Oilseed Research

Developing improved crops and practices for the Inland Northwest’s growing oilseed industry, alumnus and soil scientist Isaac Madsen is Washington State University’s new extension agronomist for the Washington Oilseed Cropping Systems program.

Hired Sept. 1, Madsen is based in Pullman, and leads WSU’s field-based testing program for oilseed crops, including canola, camelina, safflower, and sunflower. He will work alongside WSU scientists, Extension experts and Northwest growers to test and improve oilseed varieties and production methods that help diversify dryland farming in eastern Washington.

WOCS-funded Canola and Wheat Rhizosphere Study Results Published

An ongoing collaborative research project between USDA-ARS and WSU Crop & Soil Sciences faculty is producing some interesting results, some of which were recently published in the journal Applied Soil Ecology. Two of the five researchers, Dr. Tim Paulitz and Dr. Bill Schillinger, are part of the WSU-WOCS team who authored Common and unique rhizosphere microbial communities of wheat and canola in a semiarid Mediterranean environment. The project will continue to receive partial funding from WOCS as the researchers generate more data from samples collected at the long-term cropping systems site at the Ron Jirava farm near Ritzville.



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Spotlight on 2021 Oilseed Field Day Abstracts

Canola Rotation Effects on Soil Microbiology and Subsequent Wheat Yield (pdf)

Bill Schillinger1, Ron Jirava2, Tim Paulitz3, Jeremy Hansen3, John Jacobsen1, and Steve Schofstoll1

1Dept. of Crop and Soil Sciences, WSU; 2Farmer Collaborator, Ritzville; 3USDA-ARS, Pullman

We are investigating the effects of canola, winter triticale, and winter wheat on soil fungal and bacterial communities and the grain yield of subsequent spring wheat. The study was initiated in 2016 on the Ron Jirava farm west of Ritzville. These are 3-year rotations with a year of fallow after the spring wheat. Spring canola is substituted for winter canola when adequate winter canola stands are not achieved. There are 36 plots with each phase of the three, 3-year rotations present each year. Individual plots are 500 feet long and 30 feet wide.
This experiment is now in its 6th year, thus all three rotations are truly “in rotation”. We closely monitor soil water dynamics from all phases of all rotations and collect accurate grain yield data. Soil microbial activity is currently being assessed using DNA sequencing of rhizosphere soil (i.e., soil adhering to roots) as well as phospholipid fatty acid analysis (PLFA) of bulk soil. Such data can only be obtained through long-term cropping systems experiments.
During the past five years, significantly less overwinter precipitation has been stored in the soil in canola stubble in three years (Fig. 1). Averaged over the five years, canola stubble has stored significantly less over winter precipitation in the soil than winter triticale or winter wheat stubble. These differences were particularly pronounced during a winter of heavy snow accumulation in 2017. There were no significant differences in water storage among treatments during winters with little snow (such as 2019 and 2021). Average spring wheat grain yields for the first four year after canola, winter triticale, and winter wheat have been 33, 41, and 39 bushels/acre, respectively (Fig. 1).
Every year to date, spring wheat grain yields have been significantly related to soil water content measured in early April (Fig. 2). However, as can be seen from the simple linear regression equations in Figure 2, soil water content is not telling the full story on spring wheat yield. We suspect soil microbial activity may play an important role and we look forward to fully analyzing the soil DNA sequencing and PLFA data during this next year.

The Washington State University Oilseed Cropping Systems Research and Extension Program, in partnership with the Washington State Department of Agriculture, is committed to supporting the grower and industry-based movement to diversify cropping system agronomics and markets through increased adoption and production of oilseed crops.

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Samantha Crow
Administrative Assistant