ISHS Acta Horticulturae 664: IV International Symposium on Irrigation of Horticultural Crops
REGULATED DEFICIT OF IRRIGATION (RDI) EFFECTS ON GROWTH AND YIELD OF PLUM TREE |
| Author: | A. Battilani |
| Keywords: | Prunus domestica, fruit quality, gross margin, sub-humid area |
| Abstract:
A field experiment was performed to study the response of plum cv. Fortune to different water regimes and strategies. The aim of the trial, carried out in the years 1994-2002, was to identify the most suitable irrigation regimes and to test the effectiveness of RDI techniques in a sub-humid area and on a fruit crop commonly not irrigated in the region. The treatments undergoing comparison were: Rainfed; 50% and 100% ETc replacement; 100% ETc applying RDI in stages D2a and D4 and an extended RDI (RDI/A), in which stress was applied during stages D2a, D2b, D4. Irrigation significantly increased yield compared to rainfed conditions. The yield increase reflected both a larger number of fruits and higher average fruit weight. The gross margin (average 99-02) increased by 3378 € ha-1 y-1 (40.8%). Among the irrigation treatments, the effects of the RDI regimes did not differ from those obtained with 100% ETc. RDI had no effect on vegetative growth, which was similar to that observed in the 100%ETc and higher than that of Rainfed. 50% ETc resulted in a good production level and quality, similar to those obtained with 100%ETc in terms of yield and quality, while assuring higher water use efficiency and profit per unit of water resources utilised. The yield/trunk cross section area ratio, adopted as an index of yield efficiency, was higher with 100% ETc, RDI and RDI/A and 50% ETc than under rainfed conditions. Water use efficiency (WUE) was highest in the rainfed group, decreased with the 50% ETc treatment and reached its lowest with 100% ETc and RDI. WUE was better in the 100% ETc irrigation treatments when applied in conjunction with RDI techniques: in this case RDI reduced the water supply by about 35.0 %. The results show that it is possible to achieve good yield, quality, and profitability by supplying on average 78 mm y-1 of irrigation water. | |
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