- Agronomic: wheat
- Crop Production: crop rotation, fallow, nutrient cycling
- Education and Training: extension
- Energy: bioenergy and biofuels
- Natural Resources/Environment: carbon sequestration
- Production Systems: general crop production
- Soil Management: soil analysis, soil quality/health
- Sustainable Communities: sustainability measures
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.