Effect of Potassium and Phosphorus Fertilization on Green Herb Yield and Some Quality Traits of Thymus vulgaris L.

Thymus vulgaris L. (garden thyme) is a member of the Lamiaceae family and is an indigenous aromatic and medicinal plant of Europe and Asia. At present, it is cultivated majorly in North America, Europe and North Africa in a large scale due to its economic importance. Thymus vulgaris L. is not accepted as a native plant of Turkey though some taxon is existing. However, it is commercially grown. The objective of this study was to examine the effects of P and K fertilizations on green herb yield, some herb chemical constituents (N, P, K) and volatile (essential) oil of Thymus vulgaris L. in order to recommend a reliable nutrient management for commercial growers. Results showed that, yield generally increase in accordance with the increases in K and P fertilizer rates. The N and P contents of the herb were measured higher under P rich (P2) conditions (that is, 67.5 + 67.5 = 135 kg P2O5 ha-1 from 15:15:15 + Zn and phosphoric acid, respectively). The highest three volatile oil constituents (compound) of the herb were found as thymol, paracymen and carvacrol.   Key words: Potassium (K), phosphorus (P), oil contents, volatile (essential) oil compound, thyme (Thymus vulgaris L.)