Summary:

This paper presents an assessment of the impact of irrigation on the growth and yield of five varieties of plums: Hanita, Elena, President, Amers , Jojo. The plums were grown in individual fruit farm in the village of Pyzdry in Wielkopolska. The assessed plum varieties were planted on stems of Węgierki Wangenheim in the autumn of 2010, on light soil good rye complex. The influence of different irrigation was assessed after 3 and 4 years (in 2013 and 2014) after planting, because in the early years there was no applied irrigation. Irrigation was used when the soil water potential decreased below - 0,01 MPa. The sprinkler "Head" was used for irrigation with a spacing 4 x 3m. Between the rows of trees there were grassy field and rows of herbicide fallow. Before the usage of irrigation (2012) the plum yields averaged 0,8 kg • tree--1. Depending on the precipitation totals in different growing seasons in 2013 and 2014, the doses varied from 10mm to 35mm, including 90mm from the IV to the VII month of 2013 and in an amount from 15mm to 80mm, 200mm in total, in the IV to VIII month of 2014. Under the effect of irrigation, the yields increased by an average of 1,1 kg • tree-1, in the first year of irrigation (2013). The largest increase in yield due to irrigation (an average of 1,2 t • ha -1) to the amount of 3,7 t • ha-1, was found in 2014. In relation to the vegetation period of 2012 when there was no irrigation, with a similar sum and distribution of rainfall and the average air temperature, the average increase in yield was more than 3-fold. Productivity of 1mm water over a period of 2 years of irrigation resulted in 0,7 for 1mm kg • ha -1 and essentially depended on the weather conditions, especially the amount and distribution of rainfall.