Effect of soil and plant covering and sowing time on the yield of fennel bulbs grown from sowing directly in the field

A field experiment on fennel growing (Foeniculum vulgare var. azoricum Mill.) was conducted at the Experimental Farm of the University of Life Sciences in Lublin, on a grey-brown podzolic soil. The experiment included the following factors: three kinds of covers - soil covering with black polyethylene film (PE 0.05 mm), soil covering with black polypropylene non-woven fabric (PP 50 g m^-2) and flat covering of plants with white polypropylene non-woven fabric (PP 17 g m^-2); three sowing terms - April, May, June; two fennel cultivars - ‘Rudy F₁’ and ‘Zefa Fino’. Soil mulching with PP50 and, to a slightly lesser degree, black PE, caused an increase in the total and marketable yield of fennel bulbs and had a favourable effect on the yield structure. The lowest yield, with the highest share of non-marketable bulbs, was obtained following plant covering with PP17. The bulbs were the largest in the experimental treatments with PP50 mulching. The smallest bulbs were harvested following PP17 plant covering. For fennel growing, the most favourable sowing time was April. The lowest yield was obtained from the June sowings. The cultivars studied did not vary in terms of yield level and structure. The bulbs of the ‘Zefa Fino’ cultivar were longer and more slender than those of the ‘Rudy F₁’ cultivar