1Department of Microbiology and Food Technology, University of Life Science and Technology, Bydgoszcz 2Department of Crop Sciences, Division of Vegetables and Ornamentals, University of Natural Resources and Life Sciences, Vienna, Austria 3Department of Apparatuses and Food Technology, Division of Food Technology Faculty of Chemical and Engineering University of Life Science and Technology, Bydgoszcz

The influence of irrigation and nitrogen fertilization on technological and storage value of potatoes grown on a very light soil was studied during the years 2001-2003. The three two-factorial field experiments were conducted at Kruszyn Krajenski near Bydgoszcz. The following cultivars were tested: 'Drop', 'Mors' and 'Triads'. The first factor of the study was irrigation used in the two variants: O without irrigation (control plots), W - with sprinkler irrigation according to rainfall amounts during the vegetation period. The second factor was nitrogen fertilization used in the two following doses: N-1 = 75 kg N ha(-1) and N-2 = 125 kg N ha(-1). After harvest tubers were stored during six months in potato storage (air temperature 4 C, relative air humidity 95%). The content of dry matter, starch, sugars and vitamin C was analyzed in tubers after harvest and after storage. It was found that irrigation, fertilization and storage influenced the technological and storage value of potatoes. Particular cultivars were characterized by differentiated response to irrigation, fertilization and storage.

The results of the study on the content of selected chemical components of watermelon (total sugars, reducing sugars, vitamin C, carotenoids and beta-carotene) of Polish cultivar ‘Bingo’ are presented in the paper. Cultivation was conducted in two successive vegetative seasons (2005 and 2006) near Bydgoszcz, with the use of drip irrigation. During seedling production three different variants of irradiation were used: sunny light, artificial daylight and artificial blue light. The drip irrigation, used during the vegetative season, decreased the content of total sugars as well as that of carotenoids and beta-carotene in watermelon fruits, whereas the content of reducing sugars and vitamin C was higher than that in fruits obtained from control plots (without irrigation). Irradiation with artificial daylight during seedling production had a positive influence on the content of total carotenoids, beta-carotene and vitamin C in watermelon fruits. The content of sugars was differentiated in fruits of watermelon by irradiation of seedlings. Fruits of plants originated from seedlings irradiated with sunny light were characterised by the highest content of sugars.