1. Nitrogen Source and Rate Effects on Camelina Seed Yield and Biomass Production Irrigated with Sewage Effluent Wastewater in Nevada
Dhurba Neupane1, Juan Solomon2, and Jay Davidson3
1Department of Natural Resources and Environmental Sciences,
2Department of Agriculture, Nutrition & Veterinary Sciences,
3University of Nevada Cooperative Extension,
University of Nevada, Reno

2. Introduction
Finding suitable alternative crops for semiarid agriculture can be a challenging task.
However, finding viable alternative crops is extremely important for agricultural ecosystems like Nevada,
where groundwater levels are diminishing thus leading to a decline in water allocation for agriculture production.
One such crop suitable for dryland agriculture is Camelina sativa L. Crantz, an oilseed crop that is a member of the Brassicaceae Family.

3. Introduction Cont’d The favorable agronomic traits of Camelina namely:
low water use (drought tolerant),
low N requirements,
ability to grow under different climatic and soil conditions
make it a suitable alternative crop (biofuel feedstock, protein feed for animals) for dryland agriculture (Zubr, 2003; Frohlich and Rice, 2005; Pilgeram et al., 2007; Obeng and Obour, 2015).

4. Introduction Cont’d
While there are a number of studies reporting Camelina seed yield response to different N levels (e.g., Malhi et al., 2014; Jiang et al., 2013; Sintim et al., 2015),
the response to N varies with geographical locations.
Therefore, the need for studies pertaining to Camelina response to N fertilizer in Nevada’s agricultural ecosystems is warranted:
because no data are available to provide a recommendation of optimum N quantity required for Camelina production in Nevada.

5. Introduction Cont’d
Controlled-release N fertilizer may enhance N use efficiency and crops like Camelina response to lower levels of N input compared to conventional urea in semiarid agriculture production.
In addition, reclaimed water can contribute substantially to overall crop nutrition therefore, we also examine this aspect in our study.

6. Objective
To evaluate the effects of nitrogen source and rate on seed yield and biomass production of Camelina sativa.

7. Materials and Methods
Research site: Main Station Field Lab, University of Nevada, Reno NV.
The soil at the study site is classified as a Truckee silt loam (a fine-loamy, mixed, superactive, mesic Fluvaquentic Haploxerolls).
Climate: Semi-arid with average precipitation of 229 mm year_1.

8. Materials and Methods Cont’d
Soil characteristics at the research site ( ) 
Year
Organic matter pH
CEC
NO3-N P K Ca Mg Na
(%)
Meq/100 g
mg kg-1 soil
2016
4.7
7.8
25.9 14 19
560
3539
598
437
2017
6.3
7.9
23.9
7.0 44
670
3401
538
180

9. Materials and Methods Cont’d
Total monthly precipitation and mean monthly air temperature at the UNR Main Station Field Lab Reno, NV during 2016 and 2017 growing season
Months
Monthly Precipitation
(mm)
Total Monthly Irrigation (mm)
Mean Air Temperature
(0C)
2016
2017
March
17.0
20.0
14.5
7.4
7.5
April
30.7
23.3
123.1
45.0
10.6
9.2
May
28.5
17.5
199.6
206.2
13.7
14.8
June
0.00
3.56
108.5
173.9
19.6
July
0.76
24.4
56.2
22.0
23.2
Total
76.2
65.1
470.1
481.3

10. Materials and Methods Cont’d
Treatments & Experimental Design:
Four N rates (0, 40, 80, and 120 kg N ha-1)
Two N sources (conventional urea and polymer-coated urea)
Two Cultivars (Blaine Creek and Pronghorn)
Four replications of each treatment combination (4 × 2 × 2 factorial) in a RCBD experiment. 

11. Materials and Methods Cont’d
Plot Establishment & Management
Plots were 1.8 m wide × 7.6 m long with 0.6 m alleyway between plots and 1.5 m alleyway between blocks.
Plots were seeded March 18, 2016 and April 11, 2017 at a seeding rate of 5 kg ha-1 and depth of 0.5 cm using a Wintersteiger plot seeder.
Fertilizer application: All four N rates and source were applied to their randomly assigned plots 3 weeks after germination.

12. Materials and Methods Cont’d
Plot Establishment & Management
P was applied to all plots at a rate of 40 kg ha-1 and no K fertilizer was applied based on soil test recommendation.
Herbicide application: Sethoxydim (Poast) was applied at a rate of 0.5 kg a.i. ha-1 to control grass weeds.
Post emergence broadleaf weeds were controlled manually by hand cleaning.

13. Materials and Methods Cont’d
Plot Establishment & Management
Irrigation Method: Sprinkler handlines (9.1 m apart with 9.1 m spray radius).
Crop was irrigated once weekly using reference ET (DRI weather station) and crop coefficient for Camelina (Hunsaker et al., 2011).

14. Data collected SPAD Chlorophyll Index (SPAD 502 Chlorophyll Meter),
Light Interception (LI-191 SA Quantum Sensor and LI-1500G Logger),
Leaf Area Index (Plant Canopy Analyzer LAI-2200C),
Plant Height (soil level to tip of the plant canopy),
Seed and Biomass Yield (area harvested = 5.5 m2)

15. Statistical Analysis
Data were analyzed by fitting mixed models using PROC GLIMMIX MIXED in SAS.
Orthogonal polynomial contrast was done to examine trends of measured parameters in response to N rate.

16. Results and Discussions
SPAD chlorophyll index, light interception, leaf area index, and plant height of Camelina sativa at different N application rates averaged across two growing seasons (2016 – 2017) 
Parameters
N rate (kg N ha-1 ) SE
OPC 40 80
120
Linear
Quadratic
Cubic
SPAD Chlorophyll index
28.7b
29.8ab
30.8a
0.5
 0.0083
0.8210 
0.3683 
LI (%)
44.9c
52.3b
63.5a
65.9a
3.7
<0.0001
0.3452 
 0.2785
LAI (cm2 / cm2)
2.67
2.64
2.63
2.65
0.07
0.5916
0.4549
0.9597
Plant height (cm)
73.1
73.3
78.2
75.3
1.9
 0.3404
0.5554 
0.3078 

17. Results and Discussions Cont’d
SPAD chlorophyll index, light interception, and plant height of two Camelina cultivars averaged across two growing seasons (2016 – ) 
Parameters
Blaine creek
Pronghorn SE
p-value
SPAD chlorophyll index
31.5
28.0
0.4
<
Light interception (%)
57.6
55.7
3.2
0.4539
LAI (cm2 / cm2)
2.67
2.64
0.07
0.2840
Plant height (cm)
76.4
73.5
1.9
0.2965

18. Results and Discussions Cont’d
Seed and biomass yield of Camelina averaged across two growing seasons ( – 2017) 

19. Results and Discussions Cont’d
Main effect of cultivar on seed and biomass yield of two Camelina cultivars averaged across two growing seasons (2016 – 2017) 
P = , SE = 190

20. Summary
Nitrogen application rate affected SPAD chlorophyll index, and light interception of Camelina and the responses were a linear increase with increasing N rate.
SPAD Chlorophyll index was greater for cultivar Blaine creek compared to Pronghorn.
Nitrogen source had no effect on any of the measured parameters in this study.

21. Summary Cont’d
Leaf area index was not affected by N rate, N source, cultivar nor their interactions in this study.
Plant height was similar for cultivar Blaine creek and Pronghorn.
Both seed and biomass yield of Camelina increase linearly with increasing N application rate.

22. Summary Cont’d
Cultivar Blaine creek had greater seed (921 vs 645 kg ha-1) and biomass yield (2544 vs 1880 kg DM ha-1 ) than Pronghorn.
Effluent wastewater alone as indicative by the 0 N rate will not be adequate to support comparative seed production of Camelina.
The results from this study compared favorably to those reported in the literature and suggest that there is potential for growing Camelina in the state of Nevada.

23. References
Frohlich, A. and Rice, B., Evaluation of Camelina sativa oil as a feedstock for biodiesel production. Industrial Crops and Products.21:25-31.
Jiang, Y., C.D. Caldwell, K.C. Falk, R.R. Lada, and D. MacDonald Camelina yield and quality response to combined nitrogen and sulfur. Agron. J. 105: 1847–1852.
Malhi, S.S., E.N. Johnson, L.M. Hall, W.E. May, S. Phelps, and B. Nybo Effect of nitrogen fertilizer application on seed yield, N uptake, and seed quality of Camelina sativa. Can. J. Soil Sci. 94: 35–47.
Obeng, E. and Obour, A Seeding Date Effects on Camelina Seed Yield and Quality Traits. Kansas Agricultural Experiment Station Research Reports, 1(2). Available at:
Pilgeram A.L., D.C. Sands, D. Boss, N. Dale, D. Wichman, P. Lamb, C. Lu, R. Barrows, M. Kirkpatrick, B. Thompson, D.L. Johnson Camelina sativa, a Montana omega-3 fatty acid and fuel crop. In: J. Janick, A. Whipkey (eds.) Issues in new crops and new uses. ASHS Press, Alexandria, pp 129–131
Sintim, H.Y., V.D. Zheljazkov, A.K. Obour, A. Garcia y Garcia, and T.K. Foulke Evaluating agronomic responses of Camelina to seeding date under rain-fed conditions. Agron. J. 108: 349–357.
Zubr, J Qualitative variation of Camelina sativa seed from different locations. Ind. Crops Prod. 17:161–169.