ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Productivity, postharvest physiology, and soil nitrate movement as influenced by nitrogen applications to 'Delicious' apple.

Fallahi, E.;

Acta Horticulturae Year: 2000 Issue: No. 512 Pages: 149-157 Ref: 10 ref.

2000

บทคัดย่อ

Redspur Delicious apple trees on M.7 rootstock used in this experiment were planted in 1980. Urea, at five rates, was applied to the soil within the drip line of trees (1) all at full-bloom; (2) half at full-bloom and half in late spring; and (3) all in autumn. Samples were taken for leaf analysis and fruit quality was measured at harvest and after storage in 1992-94. Fruit red colour decreased with every incremental increase in the rate of applied N. Firmness of fruits from trees given 45 g N/tree was higher than that in all other treatments. Trees receiving 590 g N/tree had lower yield and smaller fruit size in 1994. High N increased fruit ethylene and respiration. Monitoring nitrate movement through the soil profile showed that application of N at 454 g/tree or greater resulted in excess levels of NO3-N in the soil, increasing the possibility of underground water contamination. Application of up to 318 g N/tree did not produce excess soil nitrate at a depth of 106-152 cm. Considering all fact

ors studied in this experiment, optimum yield, high fruit quality at harvest and after storage, and low soil nitrate were produced when leaf N concentration was about 2.03-2.16% dry weight. Under the conditions of this experiment, these levels were achieved by application of up to 181 g N/tree. Application of N at 45 g/tree or less (leaf N less than 2.03% dry weight) may not be sufficient for good yield and fruit soluble solid concentration at harvest.