ISHS Acta Horticulturae 331: WOCMAP I - Medicinal and Aromatic Plants Conference: part 3 of 4
EFFECTS OF VARIED NITROGEN FERTILIZATION AND CUTTING TREATMENTS ON THE DEVELOPMENT AND YIELD COMPONENTS OF CULTIVATED STINGING NETTLES |
| Author: | F. Weiß |
| Keywords: | Urtica dioica L., medicinal plant, nitrate, quality |
| Abstract:
During three years of field experiments (1989–1991) the effects of varied nitrogen fertilization and cutting treatments on dry matter (DM) production and yield components of cultivated stinging nettles were investigated. In the first year of cultivation, only one growth could be harvested due to a delayed plant development and a very low DM production. In the second and third year, plant development and herb yield improved considerably and four growths were harvested each year. Increasing amounts of nitrogen always significantly increased DM production of leaves and stems. In 1990, leaf yield was similar in each growth or regrowth. Maximum leaf yield of all cuts was obtained in the primary growth 1991. DM production of leaves and sems decreased significantly with each regrowth period in 1991. The leaf/stem ratio (LSR) was higher in 1991 compared with 1990 and increased with decreasing herb yield. In 1991, developmental stages of havested shoots were assessed in order to obtain an indication of the phsyiological age of the plants. The prolongation of cutting intervals in the primary growth and first regrowth period increased proportions of flowering shoots in the samples. This result stands in sharp contrast with the findings in the second regrowth. With a longer growth period flower formation was delayed. Plants harvested at the last sampling date scarcely produced unfolded inflorescences, in contrary to plants harvested at the same cutting interval, but earlier in the year. In plants cut in the third regrowth flower formation had stopped completely. Nitrate-n content of stems and leaves was significantly increased with a higher input of nitrogen fertilizer. Stems contained up to 9 times as much nitrate-n compared with leaves. Nitrate-n content also increased with each growth period. | |
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