Summary:

Irrigation in ornamental plants production is one of the most important factor guaranteed good growth of plants, their high quality and healthiness. Water needed in plants production is divided into two types: water which is needed for irrigation with main sources like streams, rivers, deep wells or even waterworks. Second type of water in plants production is natural precipitation and irrigation. Excess of this water must be drainage and transfer to ditches or retention basins. The aim of this analysis based on two models of ornamental holdings was to point out great possibilities of rainwater retention and its uses for plants irrigation. For this research two modern, different farms were chosen. One of them with greater area of container plant production (16 ha) located near Wieluń city. Other with great area of greenhouse production (3,9 ha) located near Bydgoszcz city. These farms already made some adjustments for rainwater retention from roofs and roads within farms. According to once requirement of water for 1 ha of container plant irrigation which was 21 and 22,5 m3, total yearly amount of water was determined between 2268 and 2430 m3. For greenhouse production once requirement of water for 1 ha plants irrigation was lower: 11,1 and 12,4 m3, and total yearly requirement was respectively 1454,1 and 1798 m3. In the monitored farm in Wieluń during year 2014 about of 23500 m3 of water was storage according to yearly rainfall amount 616,8 mm. In the second farm located near Bydgoszcz 25000 m3 of rainwater was stored according to yearly rainfall amount 547,2 mm. These amounts of retained water satisfied demand to whole requirement for irrigation in the farm near Bydgoszcz, and 57,2 % of total requirements for irrigation in the farm near Wieluń