The effect of the date of herbicides application and mulching on ‘Double Dazzle’ tulip flowering and bulbs yield

Abstract

One of the most important agronomic treatments during the reproduction of tulip bulbs is the protection of a plantation against weeds. For this purpose, the most frequent treatment is the use of herbicides and different kinds of mulches which not only enhance the effectiveness of chemical substances, but also – through keeping better soil humidity and decreasing temperature fluctuations –  increase the yield of plants. In the experiments conducted in the years 2009–2010, ‘Double Dazzle’ tulips from the Double Early Group were sprayed with linuron (675 and 1350 g · ha^–1) and leanacil (1000 and 2000 g · ha^–1) in different concentrations. The spraying was performed in autumn, just after planting the bulbs, 2 weeks after bulbs planting,  and in spring, in the last  10-days’ period of March. Some plots were covered with 10 cm of wheat hay. The plots were mulched just after planting the bulbs, 2 weeks after bulbs planting and when the soil had frozen.  In spring the hay was taken away from a part of the plots. Herbicides linuron and lenacil used together with mulching effectively inhibited weeds and had no disadvantageous effect on the flowering and yielding of tulips. A good effect was achieved when a mixture of 675 g · ha^–1  of linuron and 1000 g · ha^–1 of lenacil with 300 dm³ of water was applied once. The spraying may be performed up to two weeks after planting the bulbs or in spring. Early covering of the soil with hay, after planting the bulbs, and leaving it till the end of vegetation positively influences the yielding of tulips and increases the share of bulbs of the first class size. Leaving the mulch till the end of vegetation also decreases weed infestation and enhances the effectiveness of herbicides, which allows the use of lower quantities of chemical substances and water.