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

The effect of perforated polyethylene foil and polypropylene fibre cover on the development of early potato cultivars Aksamitka and Cykada was investigated. The use of the covers resulted in an increase in the soil temperature at the depth of 100 mm by 2.2 deg C at 8 a.m. and by 4.0 deg C at 2 p.m on average in the year with warm spring and by 1.5 deg C and 3.2 deg C on average in the year with cold spring, respectively. The use of perforated foil led to a higher increase in the soil temperature (by 1-2 deg C) than the use of polypropylene fibre. The increase in the soil temperature as a result of covering forced the plant emergence by 5 days on average and shortened the period from planting to tuber setting by 5 days in comparison with the cultivation with no plant covering. The favourable effect of covering was the most pronounced in the year with the lowest air and soil temperatures in May. The use of the covers at that time forced the plant emergence and shortened the period from planting to tuber setting by 6 days on average. A higher soil temperature increase was observed under the perforated foil than under the polypropylene fibre, which resulted in an earlier occurrence of the successive plant developmental phases (by 1-2 days).