Changes in N, K, and Fatty Acid Composition of Black Cumin Seeds Affected by Nitrogen Doses under Supplemental Potassium Application

Abstract

This study was carried out to determine the efficiency of nitrogen (N) doses (0, 30, 60, and 90 kg N ha(-1)) under supplemental potassium (K) application (50 kg K-2 O ha(-1)) on black cumin in 2011 and 2012. The results showed that increased N levels resulted in increasing seed yield and N and K contents in seed, while oil content decreased. The seed yield and oil yield were peaked at the doses of 60 kg N ha(-1) and 50 kg K ha(-1). An increase in N doses caused a reduction in oil content regardless of K supply. Saturated fatty acids and oleic acid were slightly increased by K application, while minor changes in linoleic acid were detected. It was concluded that 60 kg N ha(-1) with supplemental K application should be advised for enhancement in seed yield, oil yield, and N and K contents in seeds of black cumin without significant changes in fatty acid composition.