Effects of Irrigation and Nitrogen Fertilization on Growth, Yield and Fruit Quality Parameters of Peaches for Processing

The key factors to obtain good yields and high fruit quality in peach production in semi-arid regions are water availability and fertilization. The objective of the present study was to investigate the effects of different irrigation strategies and nitrogen doses on plant and fruit growth, yield and quality in peaches for processing. The experimental plot was located in a commercial orchard in the northeast of Spain (Torres de Segre, near Lleida). The test was run on 180 six-year-old Andross trees on GF 305, unthinned rootstock, which were trained on a free palmeta and planted in a shallow soil. Three irrigation treatments were evaluated according to fruit growth stage: 100% full ETc throughout the season, 70% ETc during stage II, and 30% ETc during stage III. These were combined with three nitrogen fertilization treatments: 0, 60 and 120 kg/ha. Trees were mechanically harvested using a continuum trunk shaker. The amount of water saved by reducing irrigation at either stage II or stage III of fruit growth was equivalent to 12% of the total amount of water applied. Deficit irrigation during stage II did not affect fruit quality but decreased vegetative growth and modified foliar nutrient relationships On the other hand, deficit irrigation during stage III reduced final fruit size and yield and increased fruit firmness and total soluble solids during that period. When no N was applied, fruit growing season was shortened, ripeness was earlier, firmness was reduced and red-fruit flesh colour increased. N fertilization increased leaf and fruit nitrogen concentrations but had no effect on yield.