Nitrogen Requirements of Ethiopian Mustard for Biofuel Feedstock in South Dakota

Abstract

Core Ideas Brassica carinata is a new crop in the Northern Great Plains. Best management practices including N fertilizer recommendations should be developed. Seed yield and oil yield were optimized at 84 kg ha–1 of applied N fertilizer. Seed oil concentration decreased linearly at a rate of 0.26 g kg–1 for every 1 kg ha–1 increase in N rate. Economic optimum N rate varied from 60 to 81 kg N ha–1. ABSTRACT Ethiopian mustard (Brassica carinata A. Braun) is a non‐food oilseed crop that has received attention for its potential as a low‐input biofuel feedstock suitable for production in the semiarid regions of the Northern Great Plains (NGP). Because B. carinata is a new crop to the NGP, the best management practices have yet to be developed. The objective of the study was to evaluate the effects of N fertilizer rate on seed yield, seed oil concentration, and oil yield of B. carinata and to determine the economic optimum N fertilizer rates. Field studies were conducted at two locations in South Dakota to evaluate the response of two B. carinata varieties to five N fertilizer rates (0, 28, 56, 84, and 140 kg N ha−1) during the 2015 and 2016 growing seasons. Increasing N fertilizer rate increased seed yield and oil yield, each reaching a peak at 84 kg ha−1 N and then slowly decreasing following a quadratic model. On the other hand, increasing N rate linearly decreased seed oil concentration. The economic optimum N rate ranged from 60 to 81 kg N ha−1 depending on cost of N fertilizer and the price of carinata seed. These results show that the N requirement for B. carinata is lower than that for many crops grown in the NGP, including corn and small grains. These findings confirm that B. carinata requires low N fertility and has the potential for incorporation into cropping systems in the semiarid regions of the NGP.

Carinata growth, yield, and chemical composition responses to nitrogen fertilizer management

“…In the current study, carinata mainstem height and branching patterns were regulated by N supply supporting previous findings by Alberti et al. (2019) and Pan et al. (2012).…”

“…Nitrogen is an integral structural component of amino acids and chlorophyll and a constituent of all enzymes; therefore suboptimal availability induces a cascade of biochemical, physiological, and morphological changes in carinata growth, resource allocation, and productivity regardless of growth stage (Seepaul et al, 2016;Seepaul et al, 2019a and2019b). In the current study, carinata mainstem height and branching patterns were regulated by N supply supporting previous findings by Alberti et al (2019) and Pan et al (2012). Plant height correlated positively with node numbers (r = .63, P = .0003), primary branches (r = .65, P = .0002), secondary branches (r = 0.51, P = 0.0059), and number of pods per plant (r = .71, P < .0001).…”

“…In the current study, the mean 5-yr maximum yield (2,444 kg ha −1 ) occurred at 117 kg N ha −1 . The agronomic optimum N rate in the current study is within the range previously reported for spring-planted carinata in South Dakota (Alberti et al, 2019) and Canada (Hossain et al, 2018) and winter planted carinata in Florida (84 − 150 kg N ha −1 ) Seepaul et al, 2019a).…”

Agronomic Response of Camelina to Nitrogen and Seeding Rate on the Northern Great Plains

“…Days to maturity increased in response to N rate with a rate of 140 kg N ha −1 resulting in the longest time to maturity while plants in the control treatment took the shortest time to reach maturity (Table 4). These results confirm findings from previous studies suggesting that increased N fertilization rates can result in delayed crop maturity, due to prolonged periods of vegetative growth [28,29]. Prolonged vegetative growth in the NGP would delay flowering and seed setting, the two most important growth stages determining yield potential, to later in the season (late-June-July) when high temperature and drought stress often occur.…”

Responses of soil surface greenhouse gas emissions to nitrogen and sulfur fertilizer rates to Brassica carinata grown as a bio‐jet fuel

“…Study treatments included four different rates of N fertilizer: 56, 84, 112, and 140 kg N ha −1 , and three different rates of S fertilizer: 0 (control), 22, and 45 kg S ha −1 arranged in a factorial design to make 12 treatments within each replication for both years. A previous study by Osborne et al (2019) has determined the optimum N rate for carinata is between 60 and 81 kg N ha −1 ; thus, we used the lowest N rate of 56 kg ha −1 and increased the rate at the interval of 28 up to 140 kg N ha −1 . The optimum S fertilizer required to canola, crop similar to carinata, was around 20 kg S ha −1 (Jackson, 2000); thus, based on this study, we selected three different S fertilizer rates.…”