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Abstract
Two field experiments were conducted at the Production and Research Station of the National Research Centre, El-Nubaria, Beheira Governorate, Egypt, to assess the response of growth, yield and quality parameters of potato plants as well as associated weeds to different colours (blue, white and black) of plastic mulches, biodegradable (plastic and rice straw) mulches, infrared transmitting (IRT) plastic mulch and natural herbicides (acetic acid 20 % (AA), citric acid 10 % (CA) and AA 10 % + CA 5 %) in comparison with hoeing, metribuzin and unweeded check. The highest weed control efficacy at 90 days after planting (DAP) was obtained by black plastic mulch treatment without significant difference from efficiency values of biodegradable plastic, white plastic, rice straw mulch, AA 20 % and metribuzin herbicide treatments in both seasons. Uncontrolling weeds; led to nutrient losses that reached 35.6 and 38.9 kg/fed of N, 2.3 and 2.5 kg/fed of P, 25.9 and 28.3 kg/fed of K, 196.0 and 213.8 g/fed of Mn and 227.9 and 248.6 g/fed of Zn in the 1st and the 2nd seasons, consecutively. The highest contents of chlorophyll a, b and carotenoids in potato plants were recorded in biodegradable plastic mulch at 50 DAP and in hoeing treatment at 75 DAP in both seasons. The highest plant shoot fresh weight at 75 DAP was found in black plastic mulch treatment. Weed competition with potato plants during the whole season; caused significant reduction in total and marketable yield estimated by 50.0 and 52.5 % in the 1st season and by 57.3 and 63.4 % in the 2nd season, successively. Black and blue plastic mulch treatments achieved tuber yield higher than yield in hoeing in both seasons