Tesis doctoral de Javier Domingo Martinez
Peach is an important fruit tree in the horticultural region of lleida (northeast of spain), with a progressive increase in the last years. Recent trends in peach orchards have been towards high density plantings, new cultivars and drip irrigation systems. Peach producers are interested to manage irrigation and nitrogen fertilization that affect tree growth, and may help to achieve good results in yield and fruit quality. A three year field experiment (2006-2008) on peach cv. Andross was conducted in a commercial orchard for the processing industry. Trees were unthinned and trained on a free palmeta. Trees were mechanically harvested with a continuum trunk shaker. The soil type was loam textured, well drained, with a low water holding capacity (30% volume of coarse elements and a petrocalcic horizon at 45 cm depth). Three irrigation treatments were evaluated according to fruit growth stages: full irrigation during all the growing season (fi), irrigation restriction during stage-ii (ir2, ~70% restriction) and irrigation restriction during stage-iii (ir3, ~30% restriction), combined with three nitrogen fertilization treatments: 0, 60 and 120 kg n ha-1 year-1 trees were daily fertigated. The experimental design was randomised complete block with four repetitions. Seasonal fruit growth, soil water content, trunk shrinkage, tree water status and mineral nutrition were monitored. Yield components were determined at harvest and pruning weight was determined at tree rest. Results show that daily changes of soil water content, measured with capacitance probes, could be correlated to water deficit for each development stage, and that water balance can explain the daily course of trunk shrinkage, measured with dendrometers. Irrigation restriction affected soil water content and midday stem water potential. For stage-iii, a threshold level for the onset of midday stem water potential decline was established at 0.167 m3 m-3 of soil water content. Midday stomatal conductance increased along the fruit growth period. During all years, ir2 reduced leaf k concentration, while the opposite occurred with leaf ca and mg concentration. Also ir2 increased the specific leaf weight and reduced the pruning weight. These effects were maintained although complete irrigation was restored during the stage-iii. In contrast, ir3 did not affect nutrient relations or pruning weight. N application supposed an increase in n concentration in leaves, fruits and dormant shoots, from the first experimental year. Increasing n application produced a decrease in leaf k, but an increase in leaf s. In fi trees, n application supposed an increase in fruit load, canopy size and yield. Also n application increased the water productivity index. Total yield was lower in 2006 than in 2007 and 2008, due to changes in fruit load. Nevertheless, in 2007 the effect of irrigation during stage-iii was dependent on n application, and a positive yield effect of n dose in fi trees was observed, while the opposite occurred in ir3 trees. Thus the lowest yield was obtained in the ir3 combined with n120. Under ir2, yield was independent of n application. In 2008, with higher soil water content, there was no interaction effect, and n application increased yield within all irrigation treatments. The application of ir2 during pit hardening allowed to increase the water productivity index and enhance fruit ripening, maintaining fruit quality parameters. On the other hand, ir3 reduced the fruit size and increased the total soluble solids at harvest. Among all treatments, the percentage of fruit dry matter was positively correlated with the total soluble solids. Although the highest n application delayed fruit ripening, there were no significant interaction between irrigation and n application. As an overall, in fi trees, the application of 120 kg n ha-1 year-1 provides a maximum n dose in such orchard conditions, which may be reduced under irrigation restriction.
Datos académicos de la tesis doctoral «Effects of irrigation and nitrogen supply on vegetative growth, yield and fruit quality in peaches (prunus persica l. batsch cv. andross ) for processing«
- Título de la tesis: Effects of irrigation and nitrogen supply on vegetative growth, yield and fruit quality in peaches (prunus persica l. batsch cv. andross ) for processing
- Autor: Javier Domingo Martinez
- Universidad: Lleida
- Fecha de lectura de la tesis: 21/04/2010
Dirección y tribunal
- Director de la tesis
- Josep María Villar Mir
- Tribunal
- Presidente del tribunal: ricardo Fernandez escobar
- joan Girona gomis (vocal)
- ildefonso Pla sentis (vocal)
- Juan José Alarcon cabañero (vocal)