Potassium and phosphorus as limiting factors for erucic acid in the inedible oilseed crop, Crambe

Abstract

Crambe (Crambe abyssinica Hochist.) is an oilseed crop with high in euricic acid with industrial uses in production of biodiesel, nylon, plasticizers, and lubricants. Little information is available about Crambe response to phosphorus and potassium fertilization. The aim of this study was to determine the effect of phosphate (25 and 50 P2O5 kg Fed.−1) and potassium (10 and 20 K2O kg Fed.−1) fertilization on the growth characteristics and oil quality of Crambe plants. The experiment had a randomized complete block design, and it was carried out in the Experimental Station of National Research Center, Cairo, Egypt in 2019 and 2020. The results showed that the application of potassium and/or phosphorus fertilization resulted in significant increases of all vegetative growth traits, such as plant height, number of branches, fresh weight, and dry weight as well as fixed oil content. The GC analysis of fatty acid identified eight compounds in the following order of main averages; erucic acid (50.5%), elaidic acid (23.1%), Linoleic acid (10.9%), linolenic acid (6.5%), palmitic acid (4.8%), eicosanoic acid (1.9%), stearic acid (1.3%), and oleic acid (1.0%). Phosphorus and potassium had opposite effect on the main components of Crambe oil. Erucic acid increased with potassium fertilization and decreased with phosphorus fertilization. Contrast results were shown in Elaidic acid in response to potassium and phosphorus fertilizations. These results suggested the positive effect of both potassium and phosphorus fertilization on growth and oil yield of Crambe plants as well as they considered as limited factors for Erucic acid content.