Effect of perforated foil and polypropylene fibre covers on growth of early potato cultivars

This paper presents the results of a three-year research on the effect of perforated polyethylene foil and polypropylene fibre covers on the growth of early potato cultivars at various lengths of plant covering period (2 and 3 weeks after plant emergence). Plants grown under covers were higher, produced higher mass of above-ground parts, and were characterised by a smaller value of leaf weight ratio (LWR) and leaf area ratio (LAR) compared with the cultivation without covering. In the case of plant covering for 2 weeks after emergence the mass of leaves at the time of cover removal was on average almost 2 times higher and the mass of stems over 2.5 times higher than in the cultivation without covering; the values of LWR and LAR were however smaller by 0.094 and 0.137 m/kg, respectively. At the 3-week period of plant covering the differences in the mass of above-ground parts were a little smaller than at 2-week period of plant covering, and LWR and LAR were 1.4 times and 2.3 times higher, respectively. The research showed a significant effect of type of cover used on plant growth. When perforated foil was used, plants were higher and produced more mass of above-ground parts compared with polypropylene fibre usage. The most favourable effect of perforated foil covering was observed in the year with the lowest air temperature in May; 2 weeks after plant emergence, the use of perforated foil resulted in the mass of leaves and stems 1.5 times and 2.2 times as high as with the polypropylene fibre, respectively. The differences were lower when plants were covered for 3 weeks. The use of polypropylene fibre resulted in higher LWR and LAR by 0.060 and 0.276 m/kg, respectively, after 2 weeks from plant emergence, and by 0.072 and 0.328 m/kg after 3 weeks from plant emergence.