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Advisor(s)
Abstract(s)
Pear trees (Pyrus communis L. ‘Rocha’) grafted on quince ‘BA29’ were planted in
February of 2003 at “Pêro Moniz” (“Cadaval”, Portugal) and drip-fertigated for three
years with four N levels (0, 10, 20 and 40 kg N/ha per year) using ammonium nitrate.
At planting and at the end of each season, tree height (A), trunk cross sectional area
(AST) and the number of shoots and shoot length (NL and CL) were determined.
Leaves were collected 110 days after full bloom (DAPF) and at leaf fall and were
chemically analysed for N. The onset of flowering was in 2005 and in that year the fruit
set and the yield characteristics were evaluated. Moreover, in 2005 five extra trees were
selected for each N level, and all flowers were collected and analysed. Most growthcharacteristics were irresponsive to N fertilization. In the third year the AST differed
between N levels, whereas CL responded to N supply at the end of the first year of
fertilization. The leaves N concentration varied in response to N supply. The control
presented fewer flowers and the highest N level resulted in a greater flower production.
Flower N concentration was lower at the intermediate N levels. Fruit set and yield were
not significantly different between N treatments. Fruits from the highest N level
presented lower pulp firmness and a bigger starch regression index, indicating a more
advanced maturation stage than the fruits from other N levels.
Description
Keywords
Pyrus communis fertigation biometric measurements fertirrigação análise foliar floração medições biométricas
Pedagogical Context
Citation
Publisher
APH - Associação Portuguesa de Horticultura