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Project

Optimalization of nitrogen fertilization in 'Conference' pear for improvement of fruit quality (Npeer)

To introduce the Belgian Conference pear into new export markets, a coninuous supply of high quality pears with a delicious taste en larger fruit size is required. Fruit quality includes fruit firmness, green background colour and sugar content, and is strongly related to nutrient content with nitrogen (N) playing a crucial role. Therefore, the focus of this project is on N. To get a realistic picture of the N uptake, N distribution in trees and the influence of N fertilisation on fruit quality, mature trees in production will be used. the central reserach questions of this project are the following: (1) To what extent can N fertilisation be controlled in the Conference tree and how is it distributed over the various organs of the tree?, (2) Is it possible to link spectral and ecophysiological information to the N status of the tree, so that variable rate fertilisation can be applied in the future within the framework of precision horticulture?, (3) Can N fertilisation be optimised so that fruit quality increases and becomes more uniform? There is a broad support for this project: fruit cooperatives (PO's), fruit exporters, the (organic) fertiliser industry and institutions and organisations that pursue a sustainable nutrient policy are all asking for more uniform and better Conference pear quality. The ultimate goal of this project, to design an optimised orchard-specific N ferilisation scheme for a better and more homogenous Conference fruit quality, will therefore directly contribute to improving the profitability of Flemish pear producing companies.
Date:1 Jan 2018 →  31 Dec 2021
Keywords:Conference
Disciplines:Horticultural crop production
Project type:Collaboration project
Results:The three main research questions of the project were (largely) answered:(1) To what extent can N fertilisation be controlled in the Conference tree and how is it distributed over the various organs of the tree? The N fertilisation in the Conference tree can not only be controlled by adjusting the quantity of applied N and by the method of application (spreading granular fertilizer and/or fertigation), but also by fractionating and adjusting the timing of the N dosesif necessary. The early summer application in May in zones or orchards with too many small pears with a low N content is a clear example of controlled fertilisation. This situation can have many causes, but is often linked to the soil condition. Therefore, it is important to always look at the soil map of an orchard and, if necessary, even have a soil scan done to get more detailed information and to be able to better define the zones with pears that have a too low N content. this is the baisis for variable rate nitrogen fertilisation. The results of the 15N trials in WP1 (pallox trees) and WP2 (fertigation, summer fertilisation, full soil orchard trees) have made the distribution of the absorbed N in the tree clear.(2) Is it possible to link the spectral and ecophysiological information to the N status of the tree to eventually apply variable rate fertilisation within the framework of precision horticulture? It has not yet proved possible to link spectral and ecophysiological information to the N status of the tree. However,  the project partners have already succeeded in linking the spectral information of individual leaves and fruits to their N status. This is a basis for linking spectral infromation obtained from drone images to the N status of the trees. However, this will require additional research.(3) Can N fertilisation be optimised to increase fruit quality and make it more uniform? Yes, the results of the project trials in WP1, WP2 and WP3 clearly show this and improvement of the N content of pears in problematic zones in production orchards (P4) are a proof that optimisation of the N fertilisation can increase the fruit quality and make it more uniform over the orchard.