Improved Performance of Bearing ‘Delicious’ Apple Trees with Nitrogen and Phosphate Fertilization in a Low-phosphorus Soil
Open Access
- 1 September 1986
- journal article
- Published by American Society for Horticultural Science in Journal of the American Society for Horticultural Science
- Vol. 111 (5) , 665-669
- https://doi.org/10.21273/jashs.111.5.665
Abstract
Bearing 15-year-old ‘Oregon Spur’, ‘Redspur’, and ‘Wellspur Delicious’/seedling apple (Malus domestica Borkh.) trees in a low-P (2 to 4 ppm) soil were treated over 3 years with different forms and rates of N and N + P fertilizers to overcome a severe condition pf low vigor and low yields. Fruit size and leaf N were greater on trees receiving all forms of N fertilizer than on the untreated controls. Levels of leaf P were up to 2 times greater on NH4H2P04 [mono-ammonium phosphate (MAP)] treated trees than on the controls or N-only [(NH4)2S04, NH4NO3, Ca(NO3)2 or urea] treated trees. In most instances, the higher rates of MAP (applied in 1983 and 1984) resulted in greater shoot extension and leaf weight than the controls and most of the N-only treated trees. Yield (3-year mean) was greater on ‘Oregon Spur’ and ‘Redspur’ cultivars treated with the moderate rate of MAP than in the controls or in most of the N-only treated trees.Keywords
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