Agrometeorologiczne warunki rozwoju cebuli średnio późnej w środkowo-zachodniej Polsce

On the basis of a 40 year period (1965-2004), an assessment of the effect of main agrometeorological elements on the time of growth stages, sowing, harvesting and the length of successive growth periods of semi-late onion in central western Poland was carried out. An increase in the soil and air temperature, real sunshine and air humidity deficiency distinctly shortens the length of semi-late onion vegetation, whereas a growth in the number of days with precipitation and relative air humidity lengthens it. The largest number of significant relations between the time of harvesting and agrometeorological elements occurring in all the discussed growth periods were observed in the period from the beginning of the flopping down of leaves to harvesting, where as the smallest - in the period from sowing to the end of emergence. The length of the vegetation period signifi cantly depended, first of all, on thermal conditions of soil and air in the period from the end of emergence to harvesting and on the number of days with precipitation, particularly in the period from the end of emergence to the beginning of the flopping down of leaves. On average the largest variability of agrometeorological elements during vegetation of onion was observed from the beginning of the flopping down of leaves to harvesting, whereas the least, from the end of emergence to the beginning of the flopping down of leaves.