Influence of NPK combinations at different altitudes and aspects on fruit yield, quality and leaf nutrient status of apple cv. Red Delicious

The investigations were carried out to ascertain the effect of different NPK combinations on fruit yield, quality and leaf nutrient status of apple cv. Red Delicious at different altitudes and aspects. Eight NPK combinations were tested at three altitudes and two aspects. Earliest fruit maturity was obtained with treatment N₁P₁K₁ (300g N, 150g P and 450 g K/tree), however, lower altitude and southern aspect enhanced fruit maturity. Treatment N₂P₂K₂ (600g N, 300g P and 900 g K/tree) resulted in highest fruit yield at mid altitude in southern aspect. Treatment combinations having, higher dose of potassium and lower dose of nitrogen (N₁P₁K₂ and N₁P₂K₂) manifested better fruit colour, however higher altitude and southern aspect resulted in better coloured fruits. Higher altitude also exhibited higher fruit firmness. Leaf nutrient contents were higher in treatments where their respective doses were higher. However, higher altitude and southern aspect accumulated highest leaf N, P and K contents.