Evaluation of New Oilseed Crops for Biofuels in California 1

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1 Evaluation of New Oilseed Crops for Biofuels in California 1 Stephen Kaffka, Jimin Zhang, Robert Hutmacher, Nic George Department of Plant Sciences, UC Davis Introduction: Oilseed crop trials evaluating three winter annual species for possible use as biofuel feed stocks were carried out from fall 29 until spring 213. The primary locations for these trials were the UC Westside Research and Extension Center () in western Fresno County, the UC Davis campus, in Yolo County, and near Macarthur, in Lassen County and in , and the Plant Materials Center in Lockeford.. Three winter annual oilseed species (Canola (Brassica napa, juncea), Camelina (Camelina sativa) and Meadowfoam (Limnanthes alba) were used for those trials. We examined varieties, and evaluated nitrogen and irrigation rates using a single variety each year. Only the two Central Valley trials are summarized here. In 212, work was initiated on Castor (Ricinus communis L.) in response to rising international demand for castor oil for industrial uses, and reported advances in breeding new varieties. Castor is a summer annual with climate requirements approximately similar to cotton. It is reported to be salt tolerant, and this property is being investigated at the near Five Points. At Davis in 212, variety trials were conducted using commercial hybrids from Kaiima, and a second trial with entries from an international variety comparison organized by Dick Ault of Texas Tech University. Funding for all of these trials was provided by the California Department of Food and Agriculture and the California Energy Commission. In both cases, grants support the evaluation of possible bioenergy/biofuel crops. Methods: Canola varieties from several companies (Viterra, Cibus, Kaiima) were tested over the four years and various locations. Some of these varieties differed across the three years, so average results are combinations of several varieties. Camelina varieties were provided by Sustainable Oils (now Targeted Growth), the leading developer of Camelina varieties in the United States. Some of these varied with year as well. Meadowfoam was grown only during the first two years of trials due to disappointing yields, Three meadowfoam varieties (GA-1, GA-2, and Ross (University of Georgia) were tested. A nitrogen rate x irrigation trial was fertilized at four levels (, 8, 16, and 24 lbs per acre (Canola);, 4, 8, and 12 (Camelina); and, 2, 4, and 8 (meadowfoam) applied in two applications. Bolded amounts were the anticipated recommended rate and the rate used for all variety trials. Irrigation treatments compared were spring irrigation vs no spring irrigation. In two years, late spring rains at Davis did not allow for or require additional irrigation, so these results are not presented. At, irrigation was applied based on soil conditions in spring and plant growth status. Crops were harvested at maturity and subsampled after harvest for oil content. 1 Supported by a grant from the California Energy Commission and California Department of Food and Agriculture. Contact information: Stephen Kaffka, srkaffka@ucdavis.edu; Nicolas George, nicgeorge@ucdavis.edu 1

2 Selected Results: Overall average yields across years from variety trials are presented in Table 1. Results for Camelina from (recently harvested) are also included. Results from the most recent complete year of trials are reported in figures. A complete report and production guide summarizing all four year s results is in preparation. All cultivars and all species matured two to three weeks earlier at than at Davis In Davis, these dates were typically middle to late May for Camelina and early to late June for canola when planted in November. In year one (29-21), soil crusting at the Davis site led to poor emergence. In , suspected residual herbicide damage (MCPA) at led to unexpectedly poor performance of Camelina and possibly canola. Results at these locations should be discounted. Additional trials were planted in fall 212 at locations were MCPA had not been applied to add additional observations for these species at the site. Camelina seed yields are reported for these trials, and an estimate of average oil content is used, because the oil percent has not yet been determined. In a herbicide efficacy trial with Camelina at that same year, where no residual herbicide effects were observed, the best yield treatment averaged 95 lbs per acre of seed. We believe this reflects more closely the yield that would have been observed absent herbicide residues and matches the average yield at Davis that year. 213 Camelina harvest yields have also been included. Year to year variation and site variation were highly significant for all three species. Seed yields tended to be higher at the warmer San Joaquin Valley site than at Davis, absent special conditions like residual herbicide effects. Later average maturity in Davis and cooler spring temperatures on average resulted in higher oil analyses there. Spring irrigation (approximately 6 ac in) did not influence oilseed yields for canola and Camelina crops at Davis, but did increase yields significantly at the in most years for canola and some years for Camelina. Where moisture allows, canola is always higher yielding than Camelina. In general, Camelina, with lower yields and total biomass accumulation than canola, uses less moisture to produce a crop (estimated at ac-in per year, compared to 18 to 24 ac-in). Its role in cropping systems may be as an early maturing winter annual that facilitates rotation with a spring/summer crop, or in orchards, vineyards, or dry-farmed locations where insufficient moisture for canola is available and earlier maturity is desired. Results from the growing season are considered to be non-representative but are included to illustrate how significantly climate effects can influence canola and Camelina performance. That year experienced much higher than average rainfall, with significant rainfall occurring in Davis as late as early June, combined with colder than average temperatures in March compared to other years (data not shown). Average canola yields declined that year by two-thirds from the previous year and by 75 % for Camelina. Meadowfoam crops always were lower yielding than Camelina or canola and have much lower oil contents. Meadowfoam requires high moisture conditions, but rainfall amounts and patterns in suppressed yields to nearly unharvestable levels. The evaluation of meadowfoam was suspended due to these results and an assessment that it was unlikely to find a role in cropping systems in California. 2

3 Crop Oilseed trials, Central Valley Locations, Year harvested Location Davis Davis Davis PMC Davis Yield (lb/ac) * Canola % oil Oil yield (lb/ac) (gal biodiesel eq) Camelina Meadowfoam Yield (lb/ac) * % oil (est. 35 ) (est. 35 ) Oil yield (lb/ac) (gal biodiesel eq) Yield (lb/ac) % oil Oil yield (lb/ac) (gal biodiesel eq) *suspected herbicide damage (MCPA); higher yields in shaded cells come from a herbicide trial on plots not affected by residues. Canola yield (lb/ac) Canola Kaiima11 Kaiima12 Kaiima13 VT5 Varieties Fig. 1. Varity trial yields at Davis and. Yields were suppressed at due to herbicide damage. 3

4 3 Canola Canola yield (lb/ac) N N8 N16 N24 Nitrogen levels (lb/ac) Fig. 2. Response to N fertilizer at and Davis. The pattern observed at Davis is consistant across years with optimum levels between 16 an 2 lbs N per acre at ehyeild elvels observed on average. Camelina yield (lb/ac) Camelina V1 V2 V3 V4 V5 V6 V7 V8 V9 V1 Varieties Fig. 3. Camelina variety trial results. Yields were suppresed at WSREc due to herbiicde damage. Camelina yield (lb/ac) Camelina N N4 N8 N12 Nitrogen levels (lb/ac) Fig. 4. Camelina response to N at and Davis. In most N repsonse trials, the optimum N level for Camelina is approximately 8 lbs n per acre. PMC 4

5 Castor Castor is not a new crop in California. Zimmerman et al (1958) 2 produced a UC bulletin describing its cultivation in California in They reported per ace seed yields of 14 to 18 lb/ac. New varieties are reproted to have much larger yield potential. Cator has valuable uses as an indudtrial oil and perhaps as a feedstock for biodiesel production. Variety trials were conducted in Davis, in Fresno County, in the Salinas Valley and in the Imperial Valley in Results from only the Davis variety trail are reproted here. A summary of all the trials from 212 is in preparation. Plant populations were 8, to 9, per ac and all plots were fertilized with 1 lb N per ac. Plots were planted in May and hand harvested in November and only mature capsules were picked. Oil content is being analyzed currently so oil percent is estimated based on literatue values. Castor seeds are poisonous. Castor in August. 2 Zimmerman, Miller, Knowles Castorbeans in California. Circular 468. Cal. Agric. Res. Sta. (out of print). 5

6 Castor/Davis 212 A B C D Fig. 5 Castor seed yields (lb/ac) Kaiima varieites (A:K75; B:K93;C:C854,D:C855) A B C D Fig. 6. Castor oil yields (lb/ac, oil percent estimated at 5 %) 6