Nitrogen Source and Rate Effects on Camelina Seed Yield and Biomass Production Irrigated with Sewage Effluent Wastewater in Nevada.

The objective of this study was to evaluate the effects of nitrogen (N) source and rate on seed yield and biomass production of Camelina. A field experiment was conducted at the UNR Main Experiment Station in Reno, NV during March to July 2016. There were four rates of N application (0, 40, 80, and 120 kg N ha^-1), two sources of urea fertilizer [conventional urea and polymer coated urea (slow-released)], and two cultivars of Camelina (Blaine Creek and Pronghorn) arranged in a 4×2×2 factorial combinations with four replications each in a RCBD experiment. The experiment was uniformly irrigated with sprinkler hand lines and irrigation application rate was based on reference ET (ET_o) and crop coefficient (K_c) for Camelina at different growth stages. Nitrogen fertilizer treatments were applied three weeks after seeding Camelina. Plot size was 7.6 m long × 1.8 m wide with 1.8 m alleyway between plots and blocks. Camelina was seeded on March 18, 2016, using a cone seeder at a rate of 5 kg PLS seed ha^-1. Data collected were plant height, SPAD chlorophyll index, light interception, seed, and biomass yield. The data were analyzed using PROC GLIMMIX MIXED in SAS and orthogonal polynomial contrast was done to examine surface response trends of seed and biomass production to N rates. Treatment means were considered different P < 0.05. SPAD Chlorophyll index was greater for cultivar Blaine Creek (31.03) than Pronghorn (28.7). There was a quadratic response of SPAD chlorophyll index to N rate (P = 0.0260). Light interception was only affected by N rate and the response was linear (P = 0.0016). Light intercepted by Camelina increased as N rated increased from 0 N (43.5%) to 40 N (53.4%), and then to 80 N (65.0%), but remained constant from 80 N to 120 N (64.0%). There was a linear increased in Camelina seed yield as N rate increased (P = 0.0001; SEM 282). Seed yield for the four N rates was 0 kg ha^‑1 (567 kg ha^-1), 40 kg ha^-1 (712 kg ha^-1), 80 kg N (1186 kg ha^-1), and 120 kg N ha^-1 (1081 kg ha^‑1). There were no interactions involving cultivar, N source, and N rate in this study (P > 0.05) on seed yield. There was a trend for a linear increased in biomass production as N rate increased. Nitrogen source (conventional urea vs. polymer coated [slow-released]) does not influence Camelina seed yield or biomass production.