Potassium sulfate and ammonium sulfate affect quality and quantity of camelina oil grown with different irrigation regimes

Abstract

Camelina (Camelina sativa L. Crantz) is an oilseed crop belonging to the Brassicaceae family, which is a rich source of oil (28–40 %), as well as an excellent potential source of α-linolenic acid, a precursor for omega-3 fatty acid. A two-year experiment (2017-19) was conducted to investigate the effect of potassium sulfate and ammonium sulfate on several qualitative and quantitative traits of camelina under late-season deficit irrigation conditions. The experiment was carried out as a split plot-factorial in a randomized complete block design with three replicates and irrigation regimes (regular irrigation, restricted irrigation from flowering and pod formation stages) as the main plots and a combination of potassium sulfate (0, 25, 50, and 75 kg ha−1) and ammonium sulfate (0, 25, 50, and 75 kg ha−1) fertilizers as the subplots. The results showed that studied traits (seed yield, oil content and yield, oleic acid, linoleic acid, linolenic acid, eicosenoic acid, erucic acid, and glucosinolate substances) were affected by a three-way interaction between irrigation regime × potassium sulfate × ammonium sulfate. While the seed yield, oil content and yield, oleic, linoleic, and linolenic acid were significantly decreased when drought stress treatments were applied, the eicosenoic acid, erucic acid, and glucosinolate contents were increased in such conditions. On average, by irrigation regimes, an increase in the seed yield, oil content and yield, oleic, linoleic, and linolenic acid were observed when the camelina plants were treated with the ammonium sulfate and potassium sulfate fertilizers, while the eicosenoic acid, erucic acid, and glucosinolate contents were decreased. Generally, camelina should be cultivated in the full irrigation conditions and treated with the potassium sulfate (75 kg ha-1) + ammonium sulfate (75 kg ha-1) fertilizers for achieving the maximum seed and oil yields.