The improvement in zucchini growth in climatic conditions of Poland can be achieved by soil mulching and flat covering of plants. In the years 2009–2010, in Research – Horticulture Station belonging to Department of Horticulture at Wrocław University of Environmental and Life Sciences there was conducted two-factorial experiment with the use of synthetic mulches (polyethylene black and white foil, black polypropylene agrotextile), as well as flat covers (polypropylene agrotextile, perforated foil) in cultivation of Astra cultivar of zucchini. The experiment was established according to randomized split plot design, in three replications. Zucchini was planted on 12th May. There was not recorded any influence of mulches type on total and early yield of zucchini fruits. Additional application of flat covers made of PP agrotextile and perforated foil resulted in increase in total fruit yield in relation to control treatment by 26.7% and 44%, respectively and to the yield from plots which were only mulched – average by 47.3%. When using covers, early yield was average by 40.7% and by 47.9% higher. The highest total fruit yield (99.85 t ha^-1) was obtained in cultivation on PP agrotextile mulch with a perforated foil used as cover the plants. Fruits of 8–15 cm length accumulated the most considerable quantities of vitamin C, as well as phosphorus and potassium, while in fruits > 22 cm long there was recorded the highest amount of nitrates and carotenes.

179-189