| 311-A optimal composite design was used to study water-fertilizer coupling effects to dwarfing Fuji apple tree in juvenile period. The results showed that, in the semi-arid region of Weibei Highland, a rational application of fertilizer and water could improve nutrient status and spring shoot growth of trees, and enhance early blossoming and fruit-bearing. In normal year, the precipitation could meet the water needs of young trees, while supplemental irrigation could increase spring shoot growth but was unfavorable to blossoming. Abiotrophy resulted from soil fertility inadequacy was a main limiting factor for the growth and development of apple trees in this region. The results also indicated that, by applying farmyard-manure 24 536 kg/hm2, N and K2O 459.86 kg/hm2, P2O5 321.9 kg/hm2, and supplemental irrigation 35.86 mm, the maximum shoot growth could be gained, and the blossming rate could reach 70.1% in the third year after transplanting. |