Effects of prolonged water stress on biomass yield and nutrient uptake by aerial parts of mint (Mentha × piperita L.)

Mint (Mentha × piperita L.) is a medicinal and aromatic plant known for its high-water requirement. However, water stress is an important factor limiting vegetative development of this plant. Studying the growth, productivity, and nutrient uptake of this plant under various water stress levels is necessary to optimize its fertilization programs. In this study, the effects of different water stress levels and cutting times on the fresh biomass yields and the amounts of nutrient uptake of peppermint by different aerial parts were examined in two consecutive years. The field experiment was arranged as five irrigation treatments (125, 100, 75, 50 and 25% of full irrigation), during the season of maximum water demand (June-September), applied by drip irrigation. Results showed that at all cutting times in both years, the amounts of nutrient elements taken up by the different parts generally increased in parallel with increasing water stress, while fresh biomass yields decreased. However, this increase observed in nutrient element uptake was an increase relative to the dramatic decrease in the number of plants in severe stress conditions. The effect of long-term water stress on the nutrients taken up by different parts of the plant was mostly observed in Ca, Mg, N, Fe and Cu. As a result, in mint growing under Mediterranean conditions, despite the non-significant differences, in terms of the amounts of nutrient elements taken up by aerial parts, T75 treatment which provided 25% water saving compared to T100 could be recommended for one cut and one year cultivation in practice. Severe stress levels are not appropriate in mint growing was concluded.