Effect of nitrogen fertilization on growth, cropping and fruit quality of "Sampion" apple trees during 9 years after planting
2004
Wrona, D. (Warsaw Agricultural University (Poland). Dept. of Pomology and Basic Natural Sciences), E-mail: [email protected]
The experiment was established in autumn 1993 at Warsaw-Wilanow, Central Poland, on alluvial loamy soil. "Sampion" on M.9 one-year-old unfeathered trees were spaced at 3x1 m. Herbicide strips (1 m wide) were maintained along tree rows and sward in alleyways. Beginning in 1994, five N fertilizer treatments were applied: (1) N - 0, check, without nitrogen, (2) N - 50, 50 kg N/ha, applied in early spring on the whole soil surface, (3) N - 100, 100 kg N/ha, in early spring on the whole surface, (4) N - 50 + 50, 50 kg/ha in early spring + 50 kg N/ha 5 weeks later, on the whole surface, (5) N - 50herb., 50 kg N/ha on the herbicides strips only, in early spring. Neither dose N or mode of N fertilization had any effect on the tree growth. Nitrogen fertilization had no effect on the cumulative yield of apple trees for the years 1995-02. Cropping efficiency coefficient for 8 years of bearing (1995-02), calculated in relation to the trunk cross-sectional area in autumn 2002, did not depend on N fertilization either. In 2002 fruit firmness and the content of soluble solids before and after storage was not affected by N fertilization. The percentage of fruits with blush over 75 of skin surface was affected by N fertilization. The higher dose, i.e. 100 kg N/ha, reduced the number of fruits with blush greater 75 percent of surface
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