We conducted field experiments over three growing seasons (2014 to 2016) to determine planting dates, nitrogen (N) and sulfur (S) fertility requirements of Camelina sativa in western Kansas. We also investigated the potential effects of incorporating camelina into dryland cropping systems on winter wheat and grain sorghum yields. In the first study, spring camelina varieties were evaluated at three seeding dates: early (April 3, 2013; March 17, 2014; March 18, 2015); mid (April 16, 2013; April 1 in 2014 and 2015) and late (April 30, 2013; April 15, in 2014 and 2015). Results indicates seeding date had an effect on plant stand, the number of days to flowering, and physiological maturity. In addition, our results showed the planting window for spring camelina in western Kansas is mid-March to April 20, and depends on soil moisture at planting. Averaged over the 3-years, camelina variety Blaine Creek had greater seed yield and protein content than Pronghorn and Shoshone. Except in the 2013 growing season, oil content was not different among the camelina varieties. A second experiment was conducted to determine the response of camelina to nitrogen (N) and sulfur (S) application. Treatments in this experiment were two S application rates (0 and 18 lb/ac) and four N rates (0, 20, 40, and 80 lb/ac). Nitrogen application had an effect on plant stand count, seed yield, total aboveground biomass, harvest index, and protein content, but had no effect on oil content. Averaged across S rates, seed yield ranged from 500 lb/ac with no N to 660 lb/ac when 40 lb N/ac was applied. Sulfur application had no effect on seed yield and oil content. Average oil content across treatments was 26%, whereas protein content was 34%. In the third study, we investigated the effect of crop rotation on crop yield, soil water content, soil carbon dioxide (CO2) efflux, and residue return in camelina-winter wheat rotation system. Rotation schemes in this study were winter wheat-fallow (W-F), winter wheat-sorghum-fallow (W-S-F), winter wheat-spring camelina (W-SC), and winter wheat-sorghum-spring camelina (W-S-SC). Results showed an increase in crop residue with increasing cropping intensity. Ground cover was less in W-F than the other rotation sequences. Soil CO2 efflux measured in the spring, summer, and fall were greater with W-SC compared to the other rotation sequences. Soil water content within 0-24 in. at winter wheat planting was greater in W-S-F (7.22 in.) and W-F (6.60 in.) compared to W-SC (6.02 in.), and W-S-SC (6.02 in.). Winter wheat and grain sorghum yields were not affected by crop rotation. However, camelina seed yield with W-SC (754 lb/ac) was greater than that obtained with W-S-SC (339 lb/ac). Soil profile nitrate-N within 0-24 in. at winter wheat planting was greatest in W-F (13 lb/ac) and least with W-S-SC (5.7 lb/ac). Similarly, available phosphorous ranged from 29.5 lb/ac with W-S-SC to 35.2 lb P/ac with W-S-F. Soil pH measured at winter wheat planting in fall 2016 in the surface 0 to 2 inches were 5.7, 5.6, 5.7, and 5.8 for W-F, W-S-F, W-SC, and W-S-SC respectively. Soil organic carbon ranged from 1.45% with W-F to 1.59% with W-S-F.
Water is a limiting factor in the central Great Plains, hence the adoption of wheat-fallow (W-F) rotation system. The fallow period is to allow for moisture recharge. The use of conventional tillage (CT) operations for weed control during the fallow period has resulted in insufficient crop residue return to the soil, depletion of soil organic matter (SOM), declining soil fertility, soil erosion, and inefficient water storage. In recent years, there has been a shift from W-F to wheat-summer crop-fallow, due to the introduction and adoption of conservation tillage practices such as reduced tillage (RT), and no-till (NT) during the fallow period. Reduced till and NT has helped to overcome challenges associated with CT operations, and allowed for cropping intensification. Some of the crops that have been introduced to replace portions of the fallow period in the W-F rotation system includes grain crops (corn, sorghum), legumes (soybean, cowpea), and oilseed crops (canola, sunflower). With crop intensification, the amount and diversity of residue returned to the soil is increased by the frequency of cropping, potentially increasing nutrient cycling through SOM decomposition. Despite the benefits of intensified crop production systems, identifying alternative crops that are well adapted to drier areas of the Great Plains that can fit into existing crop rotations in the region, remains a challenge.
Camelina sativa is an alternative oilseed crop that is well adapted to the water-limited environments in the Great Plains, and has the potential to be incorporated into wheat- production systems in the region. The crop is cold and drought tolerant, and require less agricultural inputs like fertilizer. The uses of camelina includes biodiesel, adhesives, animal feed, and as an oxidizing agent in food processing. The inclusion of camelina in a crop rotation system can diversify cereal-based cropping system, improve farmer income, profitability, and long term sustainability of the system. There is a dearth of information on camelina production in Kansas, which can aid in farmer adoption.
The overall objective of this research project was to develop production recommendations for camelina in dryland cropping systems in western Kansas. Specific project objectives were to; (1) determine optimum planting dates and evaluate agronomic performance of spring and winter seeded camelina genotypes (2) evaluate camelina nitrogen and sulfur fertility requirements (3) Incorporate spring- or winter-planted camelina into dryland winter wheat cropping systems in the region.
Experiment 1 – Camelina Planting Date Study
Planting date effects on spring camelina varieties were studied over three spring growing seasons (spring 2013, 2014, and 2015) at the Kansas State University Western Kansas Agriculture Research Center near Hays, KS. The varieties used in this study were Blaine Creek, Shoshone, and Pronghorn. These varieties were planted at three different dates in a split-plot design with three replications. Plot dimension was 30 ft ×10 ft, and seeds were planted at 5 lb/ac. Seeding date was the main plot, and varieties were the subplot. Seeding dates were early (April 3, 2013; March 17, 2014; March 18, 2015); mid (April 16, 2013; April 1 in both 2015 and 2015) and late (April 30, 2013; April 15, in 2014 and, 2015 growing seasons). The crops were rain-fed throughout this study. Broadcast urea was applied to each plot at 40 lb/ac two weeks after plant emergence. In 2014 and 2015, data were collected on time of flowering (taken at 50% flowering) and physiological maturity, stand count at maturity, seed yield, biomass yield, and harvest index. After harvest, the seeds were analyzed for oil and protein content using the Antaris II FT-NIR spectrophotometer Analyzer. All data were subjected to statistical analysis using the Proc Mixed procedure in the SAS 9.3 software package (SAS Institute Inc., Cary, NC). Yield data collected for the three years were analyzed together, with variety and sowing date treated as fixed effects in the model.
Winter camelina variety × seeding date study was carried out using three winter varieties (Joelle, Bison, and BSX-WG1). The varieties were planted at three seeding dates for each year: early seeding (October 3, 2013; October 7, 2014); mid-seeding (October 17, 2013; October 17, 2014), and late seeding (October 31, 2013; October 24, 2014). Urea was broadcast applied at 50 lb N/ac in the Spring. Due to winter kill in 2014/2015 growing season, results will be presented for only 2013/2014 growing season.
Experiment 2 – Camelina Nitrogen and Sulfur Fertility Requirements Study
The experimental design was a randomized complete block with four replications in a split-plot arrangement. Individual plot sizes were 30 ft ×10 ft. Fertilizer treatments were 0, 20, 40, and 80 lb/ac N, and S rates of 0 and 18 lb/ac. Sulfur was the main factor, and N application rate was the sub-plot factor. Blaine Creek, a commercial spring camelina variety, was planted in this study at 5 lb/ac. The camelina was planted with a no-till drill into wheat stubble in 2013 and 2015, and sorghum stubble in 2014. Half-doses of the N fertilizer treatments were applied at the time of planting, and the remaining half-doses were applied after emergence. Over the growing season, data collected included stand count, biomass yield, and seed yield (adjusted to 8% moisture). Oil content was analyzed after seed harvest using FT-NIR Near-Infrared spectrophotometer (NIRS). Seed N was analyzed using Leco CN Analyzer, and then used to determine the protein content.
Experiment 3 – Wheat-Camelina Rotation Study
This experiment comprised of four rotation schemes, and these were: winter wheat-fallow (W-F), winter wheat-sorghum-fallow (W-S-F), winter wheat-spring camelina (W-SC), and winter wheat-sorghum-spring camelina (W-S-SC). The treatments were arranged in a randomized complete block design with four replicates. All phases of the crop rotations were present in each block during each year of the study. Plot size was 35 ft × 20 ft. Winter wheat was planted in October of each year. Whereas spring camelina, and sorghum were planted in mid-April, and the first week in June respectively. Before initiating the study, 60 lb P2O5/ac was applied to the entire study area. During each growing season, N fertilizer in the form of urea was applied at 60 lb/ac to winter wheat, and grain sorghum, and 40 lb/ac to camelina. Grain yields were determined by harvesting 5 ft × 35 ft from the middle section of each plot using a small combine harvester. After harvesting camelina, oil and protein content were determined using the Antaris II FT-NIR Spectrophotometer Analyzer. Soil CO2 efflux was measured at regular interval using LI-8100 automated CO2 efflux system (LI-COR Biosciences, Lincoln, NE, USA). Soil moisture at wheat planting was taken at 0-40 in. using a neutron probe. At the end of camelina harvesting in summer, crop residue was collected using 2 quadrats per plot, and oven-dried at 149oF. Assessment of ground cover was done using the stick method. Soil samples were taken at winter wheat planting from 0-2 in.; 2 to 6 in., 6 to 12 in.; 12 to 24 in. and analyzed for soil chemical properties following standard soil test procedures.
Experiment 1 – Spring Camelina Planting Date Study
Time to flowering and physiological maturity
Time to flowering was not different among camelina varieties when seeded early in 2013. However, when seeded at later dates, Shoshone flowered late (54 DAP for mid, and 56 DAP with late seeding) compared to Blaine Creek (47 DAP for mid-and 44 DAP with late seeding) and Pronghorn (47 DAP for mid; 44 DAP with late seeding). In 2014, time of flowering did not differ among varieties when planting was done early (58 DAP) or mid seeded (49DAP). Pronghorn (44 DAP) flowered earlier than Shoshone (51 DAP) or Blaine Creek (55 DAP) when planted late. In 2015 growing season, the three camelina varieties flowered at the same time when seeded early (57 DAP), mid (46 DAP), and late (44 DAP).
In general, delaying seeding resulted in reduced number of days from planting to maturity. For instance, the number of days from planting to maturity in 2013 with early, mid, and late seeding were 93, 80, and 66 DAP respectively, regardless of camelina variety. With an earlier seeding date in 2014, Blaine Creek matured later (93 DAP) compared to Pronghorn and Shoshone (90 DAP). However, Pronghorn matured earlier (88 DAP) than Blaine Creek and Shoshone (93 DAP) with a mid-seeding date. When seeded late Pronghorn and Shoshone matured at 85 DAP, which was 8 days earlier than Blaine Creek (93 DAP). Then number of days to maturity was not different among camelina varieties with early or mid or delayed seeding in 2015. Averaged across varieties, time to maturity was 92, 81, and 69 DAP with early, mid, and late seeding respectively.
Camelina stand count, seed and biomass yield
Seeding date had an effect on stand count in 2014. With an early seeding date, stand count for Blaine Creek and Shoshone (5 plants/ft2) were not significantly different, but had greater stand count than Pronghorn (4 plants/ft2). Pronghorn (7 plants/ft2) had the highest stand count with a mid-seeding date and was statistically greater than Blaine Creek (4 plants/ft2) and Shoshone (5 plants/ft2). With late seeding date, Shoshone (11 plants/ft2) had the highest stand count greater than that of Pronghorn (8 plants/ft2) and Blaine Creek (6 plants/ft2). In 2015, plant stand was poor at early seeding, however Blaine Creek (2 plants/ft2) and Pronghorn (2 plants/ft2) had more plants than Shoshone (1 plants/ft2). When seeded at later dates, Blaine Creek had greater stand count (7 plants/ft2 for mid, and 7 plants/ft2 for late seeding) compared to Pronghorn (5 plants/ft2 for mid, and 6 plants/ft2 for late seeding), and Shoshone (4 plants/ft2 for mid, and 4 plants/ft2 for late seeding).
Blaine Creek produced the greatest seed yield and was significantly greater than Pronghorn and Shoshone (Fig. 1a). Yield across varieties ranged from 340 to 440 lb/ac. In 2013, seed yield across all seeding dates was not significantly different, but in general the yield in 2013 was lower compared to the other years. This could be attributed to low precipitation during the growing season in 2013 (6.6 in.) compared to 2014 (11.3 in.), and 2015 (8.5 in.). There were differences in seed yield among varieties in 2014 and 2015. In 2014, late seeding produced the highest camelina yield, and was significantly different from early seeding. Seed yield of mid and late seeding dates were not significantly different. In 2015, seed yield was not significantly different for mid and late seeding dates, but they were significantly greater than seed yield with an earlier seeding date (Fig. 1b).
Figure 1. (A) Average camelina variety yield across three years (2013, 2014, and 2015), (B) Camelina yield at early, mid, and late seeding dates in year 2013, 2014, and 2015, Agricultural Research Center–Hays; comparison is among planting dates within year. Within years, means followed by the same letter (s) are not significantly different at P>0.05.
In 2014, biomass produced with mid (2487 lb/ac) and late (2597 lb/ac) seeding dates was not significantly different, but they were greater than early (1685 lb/ac) seeding date. In 2015, late seeding resulted in high biomass production (3957lb/ac), greater than that of early (1615 lb/ac) and mid-seeding dates (2487 lb/ac). In 2014, harvest index was different among seeding dates. Harvest index in 2015 was greatest with late seeding date (0.17) and was significantly greater than mid (0.15) and early seeding dates (0.11). At early seeding, harvest index was greatest with Pronghorn (0.20), and was significantly greater than Blaine Creek (0.16) and Shoshone (0.15). There was no difference in harvest index among varieties with a mid-seeding date (0.18). When seeded late, harvest index was not different between Blaine Creek (0.19) and Shoshone (0.21), but they were greater than that of Pronghorn (0.15).
Camelina Oil and Protein Content
In 2013, oil content was similar in Pronghorn (27.5%) and Shoshone (26.3%), but they were greater than oil content in Blaine Creek (24.2%). In 2014 and 2015, there was no difference in oil content among the camelina cultivars. Average oil content in 2014 and 2015 was 30.1% and 26.9%, respectively. In 2014, there was significant difference in protein content among the camelina varieties for early and mid-seeding dates. Pronghorn had the greatest protein content at mid (30.3%) and early (29.9%) seeding dates and was different from Shoshone (29.1% for mid, and 29.3% for early planting). When seeded late, Blaine Creek (30.7%) had the greatest protein content and was greater than the other varieties (29.7% for Pronghorn, and 29.5% for Shoshone). In 2015, Pronghorn had the greatest protein content at early seeding (29.9%) and was greater than Shoshone (29.1%). At mid-seeding date, Blaine Creek had the greatest protein content (29.7%) and was greater than Pronghorn (29.6%) and Shoshone (29.5%). At late seeding, Pronghorn (29.8%) had the greatest protein content and was statistically different from the other varieties (29.5% for Blaine Creek, and 29.2% for Shoshone). Average protein content for the two years (2014 and 2015) across varieties was 30%.
Winter Camelina Seeding Date Study Winter camelina performance was not consistent. We obtained yields only in one (2014) out of two growing seasons (2013 to 2015). Averaged across two planting dates, winter camelina seed yield in 2014 were 403, 371 and 415 lb/ac for BSX-WGI, Bison and Joelle, respectively. Due to inclement weather conditions in 2014-2015 growing season, there was severe winterkill and none of the varieties survived the winter.
Experiment 2 – Camelina Nitrogen and Sulfur Fertility Requirements Study
Stand count when no N was applied (9.3 plants/ft2) was greater than with N application at 20 lb/ac (8.2 plants/ft2), 40 lb N/ac (8.5 plants/ft2), and 80 lb N/ac (8.2 plants/ft2). Total aboveground biomass and seed yield responded positively to N application rate (Fig. 2a). Camelina seed yield increased with N application rate with maximum yield of 660 lb/ac occurring at 48 lb N/ac, beyond which there was no yield benefit to N fertilizer application (Fig. 2b). Seed yield differed over the 3-years of the study. Averaged across N and S rates, seed yield in 2013 was 361 lb/ac, which was less than that obtained in 2014 (662 lb/ac), and 2015 (735 lb/ac). Sulfur application had no effect on seed yield, oil and protein content. Similarly, N application had no effect on camelina oil and protein content. Protein content ranged from 31.8% with no N fertilizer to 32.1 when 80 lb/ac N was applied. Camelina oil content varied over the 3-years, and ranged from 21.4% in 2013 to 31.1% in 2014.
Fig 2. Effect of nitrogen on camelina biomass and seed yield
Experiment 3 – Wheat-Camelina Rotation Study
Crop residue and soil moisture
Ground cover increased with increasing cropping intensity. W-S-SC (92%) had more ground cover, followed by W-SC (82%), W-S-F (82%), and W-F (67%). More residue biomass was measured in W-S-F (3379 lb/ac), and was greater than W-S-SC (2961 lb/ac), W-SC (1959 lb/ac), and W-F (1342 lb/ac). Soil moisture in 0 to 24-inch depth at wheat planting in the fall of 2014 was greatest in W-S-F (7.2 in.), followed by W-F (6.6 in.), W-SC (6 in.), and W-S-SC (6 in.). However, soil moisture measurement in July 2015, (at camelina harvesting) was not different among the crop rotation schemes. At camelina harvesting in 2015, volumetric water content in the different rotations were W-F (0.33), W-S-F (0.29), W-SC (0.27), and W-S-SC (0.26). At winter wheat planting in 2015, volumetric water content at the upper 12-inches of the soil was greatest in W-F (0.30), followed by W-S-F (0.18), W-S-SC (0.12), and W-SC (0.04). Similarly, volumetric water content measured in the upper surface before camelina planting in March 2016 was greatest in crops rotations that had fallow. Soil moisture content with W-F (0.33), and W-S-F (0.32), were greater than W-SC (0.27), and W-S-SC (0.28).
Soil CO2 efflux
At camelina harvesting in July 2015, soil CO2 efflux was greater in W-SC (26.5 lb/ac/h) than W-F (12.8 lb/ac/h), but it did not significantly differ from W-S-F (23.5 lb/ac/h), and W-S-SC (20.6 lb/ac/h). After winter wheat planting in November 2015, soil CO2 efflux in W-SC (8.2 lb/ach) was significantly greater than that with W-F (3.2 lb/ac/h), W-S-F (4.4 lb/ac/h), and W-S-SC (4.7 lb/ac/h). At camelina planting the following year in March 2016, soil CO2 efflux was significantly greater in W-F (14.2 lb/ac/h) than W-S-F (7.7 lb/ac/h), and W-S-SC (7.6 lb/ac/h). Soil CO2 efflux in W-F, and W-SC (11.4 lb/ac/h) were not significantly different.
Camelina, sorghum, and winter wheat yields
Average camelina seed yield over the two growing seasons (2015 and 2016) was 546 lb/ac. When camelina was planted after winter wheat (W-SC), seed yield was 754 lb/ac. However, when camelina was planted after sorghum in a 3-yr rotation (W-S-SC), yield was reduced to 339 lb/ac. Winter wheat and grain sorghum yields decreased with increasing cropping intensity, but the yield differences did not significantly differ. Averaged across the 2-years, winter wheat yield was 2016, 2066, 1744, and 1710 lb/ac for W-F, W-S-F, W-SC, and W-S-SC respectively. Grain sorghum yields over the 2-years were 3334 lb/ac with W-S-F and 3298 lb/ac when sorghum was planted with camelina in the rotation.
Soil Carbon, N, P, and pH
Soil profile NO3-N measured in the upper 0 to 24-inches of the soil in 2016 at winter wheat planting was greater with W-F (13.0 lb N/ac), than in W-S-F (7.4 lb N/ac), W-SC (7.9 lb N/ac), and W-S-SC (5.7 lb N/ac). Soil pH at 0 to 6 in. depth at the beginning of the study was 6.8. Soil pH measured at winter wheat planting in fall 2016 in the surface 0 to 2 inches were 5.7, 5.6, 5.7, and 5.8 for W-F, W-S-F, W-SC, and W-S-SC respectively. Soil phosphorous measured at 0 to 2 in. depth did not show differences among rotation schemes. Soil carbon at 0 to 2 in. depth differed among rotation schemes. Soil carbon was greatest with W-S-F (1.59%), followed by W-SC (1.52%), W-S-SC (1.46%), and slightly less in W-F (1.45%).
Educational & Outreach Activities
Thesis and dissertation Assessing Camelina sativa as a fallow replacement crop in wheat production systems. Doctorate of Science Thesis, Kanas State University (in progress).
Obeng, E., Augustine K. Obour, Nathan O. Nelson, Ignacio A. Ciampitti, Donghai Wang, Timothy Durrett, and Jose Aznar Moreno. 2017. Seeding date affected camelina seed yield and oil quality traits in the semi-arid Great Plains. (In preparation).
Obour, A.K., E. Obeng, Y. Mohammed, I.A. Ciampitti, T.P. Durrett, J.A. Moreno, and C. Chen. 2017. Camelina seed yield and fatty acids as influenced by genotype and environment. Agron. J. (in press).
Obeng, E., A. Obour, and N.O. Nelson. 2016. Nitrogen and sulfur fertilization effects on Camelina sativa in west central Kansas. Kansas Agricultural Experiment Station Research Reports: Vol. 2: Iss. 6. http://dx.doi.org/10.4148/2378-5977.1235.
Obeng, E., A. Obour, and N.O. Nelson. 2016. Seeding date effects on camelina seed yield and quality traits. Kansas Agricultural Experiment Station Research Reports: Vol. 2: Iss. 5. http://dx.doi.org/10.4148/2378-5977.1228.
Obeng, E., and A. Obour. 2015. Seeding date effects on camelina seed yield and quality traits. Kansas Agricultural Experiment Station Research Reports: Vol. 1: Iss. 2. http://newprairiepress.org/kaesrr/vol1/iss2/11/.
Obeng, E., and A. Obour. 2015. Nitrogen and sulfur fertilization effects on Camelina sativa in west central Kansas. Kansas Agricultural Experiment Station Research Reports: Vol. 1: Iss. 3. http://newprairiepress.org/kaesrr/vol1/iss3/9/.
Obour, A.K., H.Y. Sintim, E. Obeng, and V.D. Jeliazkov. 2015. Oilseed Camelina (Camelina sativa L. Crantz): production systems, prospects and challenges in the USA Great Plains. Adv. Plants Agric. Res. 2(2): 00043. DOI: 10.15406/apar.2015.02.00043.
Obeng, E. 2017. Assessing Camelina sativa as a fallow replacement crop in wheat production systems. Kansas State University 3MT Presentation, February 8, 2017.
Obeng, E., A.K. Obour, N.O. Nelson, I.A. Ciampitti, and D. Wang. 2016. Response of dryland camelina to nitrogen and sulfur fertilizer. In Proc. of the Great Plains Soil Fertility Conf., 2016. Vol. 16:200-207. Denver, CO. March 1-2, 2016.
Obeng, E., A.K Obour, N.O. Nelson, I.A. Ciampitti, and D. Wang. 2016. Soil Water Content, CO2 Flux, and Crop Yields in Wheat-Camelina Cropping System. ASA-CSSA-SSSA International Annual Meeting, Nov. 6-9, 2016. Phoenix, AZ. In ASA-CSSA-SSSA Abstracts 2015 [CD-ROM]. ASA, CSSA, and SSSA, Madison, WI.
Obeng, E., A.K. Obour, N.O. Nelson, and A.I. Ciampitti. 2015. Performance of camelina (Camelina sativa L. Crantz) under semiarid conditions in central Great Plains, USA. ASA-CSSA-SSSA International Annual Meeting, Nov. 15-18, 2015. Minneapolis, MN. In ASA-CSSA-SSSA Abstracts 2015 [CD-ROM]. ASA, CSSA, and SSSA, Madison, WI.
Camelina will be a good fallow replacement crop for farmers in Kansas. Our study showed delaying the time of seeding until soil moisture availability in the spring significantly increased stand establishment and camelina yield. In addition, we identified high yielding variety (Blaine Creek) that is suited to the relatively warmer summer growing conditions in western Kansas. Our findings showed camelina required about 40 lb N /ac, which supports previous assertion that camelina has low N requirement, which makes it a good crop choice for low input agriculture. Low N requirement is going to reduce the cost of crop production. Although growing camelina in place of summer fallow reduced soil moisture content at winter wheat planting, our preliminary findings showed no significant effect on winter wheat and sorghum yields. Camelina yields were high in the 2-yr rotation scheme, however camelina yields was reduced when it was planted after sorghum in the 3-yr rotation scheme (W-S-SC). Wheat and sorghum yields were unaffected when camelina was incorporated into the rotation system. Therefore, with market availability, adopting biofuel feedstock like camelina has the potential to diversify cereal-based crop production systems in the Great Plains and provide additional farm income. Besides, camelina planted in place of fallow would increase surface residue levels, which in turn helps to lessen wind erosion. This later impact is particularly important in the semi-arid Great Plains because residue levels are generally very low, predisposing fallow fields to wind erosion from high prevalent winds.
Currently, there is no market for camelina for biodiesel production in Kansas. The few farmers growing camelina are using it as a cover crop. Nevertheless, camelina has good attributes (low fertilizer requirements, short growing season, drought and cold tolerant) as an added rotation crop in dryland crop production and several industrial uses. With market availability, camelina could be the “next big crop” in water-limited environments in the US Great Plains.
Areas needing additional study
Growing high yielding crops is an integral part in accelerating farmer adoption of new crops. Winter camelina was negatively affected by inclement weather conditions which included less soil moisture availability at planting, and snow cover that resulted winter kill. This posed a big challenge to winter camelina establishment. Perhaps winter varieties evaluated may not be the best fit for the study location. Notwithstanding, weather conditions do vary from year-to-year in the Great Plains. Hence, evaluation of adopted winter camelina varieties should be given further consideration. Planting winter camelina at an earlier date, between mid to the ending of September can be considered. In addition, evaluating additional winter camelina varieties could address these challenges of winter survival. Differences in yearly seed yield response was observed in spring camelina varieties. In addition, the spring camelina seed yields in our current study were less than those reported in cooler regions in the Great Plains. This observation could be attributed to relatively warmer air temperatures and less soil moisture during flowering and seed development. Notwithstanding, seed yield of spring camelina increased in years of more moisture supply, and relatively cooler spring and summer air temperatures. We also observed an increase in oil content when camlina was planted, and harvested early. Developing and selecting camelina genotypes tolerant to heat stress will improve seed yield, oil content and fatty composition of camelina grown in the central Great Plains. Additional research is also needed on weed control options when camelina is planted in rotation with winter wheat or grain sorghum. Our findings showed camelina can be grown in rotation with winter wheat and grain sorghum, but readily available market for camelina seed is needed before growers can adopt the crop. Bio-product processing facilities, that process oilseed crops like canola, and sunflower are good avenues that can be considered.