Vegetative Growth, Fruit Set, Yield and Fruit Quality of "Le-Conte" Pear Grown Under Calcareous Soil Conditions as Affected by Different Levels of Nitrogen, Phosphorus and Potassium

Abstract

"Le-Conte" pear fruiting trees grown in newly reclaimed soils were fertilized with different levels of nitrogen, phosphorus and potassium fertilization during three successive seasons of 2006, 2009 and 2010. However, results were calculated for the two seasons of 2009 and 2010. Tree vegetative growth (shoot length and diameter and leaf area), fruit set, yield increased significantly with increasing fertilization level. Fruit quality was increased significantly with increasing fertilization rate. The results also indicated that increasing N, P and K fertilization level lead to a gradual increment in leaf N, P and k content. Total sugars in fruits increased significantly with increasing the fertilization levels. On the other hand, starch decreased gradually with increasing the fertilization levels. The most effective level (650g. Ammonium nitrate + 325g. Potassium sulphate + 600g. Calcium superphosphate) leads to the highest vegetative growth, mineral leaf content, fruit yield and the best fruit quality as compared with other levels of fertilization. The lowest vegetative growth, yield and fruit weight and dimensions were recorded at the lowest level (250g. Ammonium nitrate + 125g. Potassium sulphate + 200g. Calcium superphosphate)