Influence of irrigation on growth, yield and fruit quality of plum trees cv. valor grafted on two rootstocks

The climate of Poland is characterized by high variability, especially regarding sum of precipitation and its distribution in the season. Dry years occur periodically. Repeated negative climatic water balance for vegetative season is insufficient for proper growth and development of plants. In this experiment we studied effectiveness of drip irrigation in plum tree cultivation. The study was carried out since 1990 to 1996 in the orchard of Institute of Pomology and Floriculture in Skierniewice. Trees of plum cv. : Valor, grafted on the Myrobalan and Wangenheim Prune seedlings were planted in spring 1990 at a distance 4,2 x 2,9 m. Influence of drip irrigation on trees growth changes, yield and fruit quality depended on weather conditions in individual years. Generally, drip irrigation significantly increased the tree growth, yield and fruit quality. Higher positive effect of irrigation was obtained for plums grafted in Wangenheim Prune seedlings than on Myrobalan seedlings.