Traditional apple orchards are being replaced by high-density irrigated systems in which fertigation is used to apply nitrogen (N) and other nutrients. Nitrogen is applied in greater amounts than any other plant nutrient but fruit trees acquire only about 20% of applied N. Among the factors that affect N use efficiency are the fertigation rate, frequency of application and the irrigation regime. Excess irrigation water can leach N below the root zone and reduces N use efficiency. Excessive N nutrition may also increase vegetative growth and reduce fruit quality and storage potential. New guidelines are needed to improve the efficiency of N fertiliser use in intensive apple production.
- To optimise nitrogen fertiliser use efficiency in high-density apple orchards at East Malling Research (EMR)
- To improve profitability and sustainability of fertigated high-density UK apple production
- To quantify nitrate leaching in high-density ‘Gala’/M.9 and ‘Braeburn’/M.9 orchards under a commercial fertigation/irrigation scheduling regime
- To investigate the effects of fertigation on soil acidification
- To schedule fertigation to match demand with supply and minimise nitrogen leaching in high-density apple orchards
- To determine the effects of the fertiliser regimes on components of apple quality and storage potential
- To disseminate the results to the industry