Effect of Rapid or slow release nitrogen supply and cover crop/weed management on crop yield, pest incidence and fruit quality in intensive organic apple production

Summary

Apple is the commercially most important top fruit crop grown in the European Union.
In spring 2001 one-year-old trees of the apple variety ‘Ingrid Marie’ were established in an organic production system with 3.0 m between the tree rows. Each plot consisted of three semi-plots at planting distances 0.6m (5555 trees ha-1), 0.9 m (3333 trees ha –1) and 1.2 m (2777 trees ha-1). Tree growth, soil moisture, soil-, leaf- and branch analysis, diseases, fruit production, outer and inner fruit quality were measured.
The healthiest trees with the best coloured fruits were produced on trees grown in weed. But the yield was so low that production was not economical. A high production combined with trees less infected with fruit tree canker and with a satisfactory colouring was produced on trees grown in intensive production system of 5555 trees per ha with no nitrogen supply.