Effect of Soil Type and Nutrient Status on the Yield and Composition of Tagetes Oil (Tagetes minutaL.)

Abstract

A glasshouse fertilizer trial (omission principle) was conducted to investigate the effect of the nutrient status of three problem Ciskei soils on the yield and quality of the essential oil of Tagetes minuta L. Acute inherent deficiencies of N and P (3 soils) and S (2 soils) were reflected in drastically reduced herbage and oil yields. N-deficiency also resulted in a dramatic increase in the dihydrotagetone content of the oil. The major oil components were not materially influenced by P and S deficiencies in the substrate. In two soils, a vesicular-arbuscular mycorrhiza developed on the minus P treatments partly alleviating the phosphorus deficiency. Results strongly suggest that inherent N, P and S deficiencies are responsible for variation in the yield and composition of T. minuta oil in Ciskei.