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Abstract
Traditionally, peach cultivation used to be dominant in Egypt’s rainfed areas. Recently, peach trees have been cultivated in the newly reclaimed areas where the low pressurized irrigation system proved to be the most efficient system of water application. No recommendations are yet available for use of regulated irrigation strategies in such area. The present work was devoted to provide such information aiming to optimizing growth, flowering and fruit set of young peach plants. The work involved, in addition, calculation of water use (WU) and crop coefficient ”Kc” with special emphasis on irrigation water saving.
The experiment was carried out on two and three years old Flordaprince peach trees (Prunus perseca L. Batsch) budded on Nemagard rootstock, in high density farm, under drip irrigation system. The duration of the experiment was two successive seasons (2003 and 2004).
Different five factors (F) were used for scheduling the irrigation program of five irrigation treatments (T1 to T5), for three distinct growth stages (initial, mid and the final stages). These factors were as follows: T1 = 0.25, 0.70, 0.45, T2 = 0.35, 0.80, 0.55, T3 (control) = 0.45, 0.90, 0.65, T4 = 0.55, 1.00, 0.75 and T5 = 0.65, 1.10, 0.85, respectively.
The results indicated that water use (WU) for the initial stage (February and March) reached about 42.20 and 56.27 mm under T3 the best irrigation treatment for the two seasons respectively. As for the mid stage (April, May, June and July), T4 treatment was recommended for this period where the water use (WU) reached about 621.23 and 804.04 mm for the two seasons respectively. Meanwhile, the water use (WU) of the
final stage under T3 treatment was about 252.41 and 253.26 mm for (August and September) for the two growing seasons respectively. Mid stage considered as a critical growth period for early peach cultivar (Flordaprince) consuming 63.95 % and 69.46 % of the total water use (WU) in comparison with 5.16 % and 5.55 % and 30.89 % & 24.99 % for the initial and the final stages, respectively. The initial stage behaves as a phenological stage where plants are less sensitive to water deficit.
The recommended crop coefficient ”Kc” for young peach trees were 0.24 and 0.33 for the initial stage, 0.75 and 0.97 for the mid stage and 0.65 and 0.65 for the final stage for two growing seasons respectively. Regulated deficit irrigation (RDI) could save irrigation water by 20 % in comparison with the common practice used by growers.
The results also, indicated that the vigorous vegetative growth expressed as trunk and branch diameters, shoot extension and leaf area were obtained up to (T3) treatment, this is for the initial stage when the growth took place during the first two months (February and March). As for the mid stage which considered a critical growth period, for young peach trees, a very high growth activity was proved during this period. Accordingly, the highest irrigation level T4 gave the best growth properties. Meanwhile, and concerning the final stage which continued during the last two months (August and September) of the growing season appeared the same trend of the first growth stage. Pruning fresh weight increased as the irrigation water increased.
The growth activity of young peach trees were slowed down under the first three irrigation treatments (T1, T2 and T3) during the commence and the dormancy stage. Accordingly the highest percentage of floral buds and fruit set were detected under these treatments.
Concerning the effect of irrigation treatments on the chemical constituents, the highest percentage of chlorophyll was under T1 up to T4, but the least values were under T5. Leaf N and P % decreased gradually as irrigation was increased in both seasons. Leaf K % increased from T1 up to T5 with no significance between T4 and T5, whereas no trend was observed concerning the effect of irrigation treatments on leaf Ca %.