The aim of this paper is to analyze the changes in air temperature between 1966 and 2005 and their effect on the phenological phases of onion, on an example of a mid-late Polish variety. To this end, we used monthly and seasonal measurements of air temperature in Poland (mean, minimum and maximum) during the onion growing season (March-September), collected from 50 meteorological stations. We also used phenological and agrotechnical data from 17 experimental stations, recorded between 1966 and 2005. Based on a linear regression function, we determined the trends of phenological phases, agrotechnical dates, the agrophenological seasons for the onion, the mean and extremes for air temperature in the months from March to September, and also across the whole March to September growing season. We also determined changes over the 40 examined years of measurements. If these trends persisted - slightly earlier emergence and leaf bending onions of mid-late varieties will develop in different light, temperature and humidity. The consequence of these changes will be increasingly shorter growing seasons and probably more difficult conditions for the onion crop in Poland.

Allium Cepa L.; trends in phenology of onion; air temperature changes in Poland

Published by University of Zagreb, Faculty of Agriculture, Zagreb, CROATIA
Sponsored by Ministry Science and Education of the Republic of Croatia