Effects of autumn foliar application of ¹⁵n‐urea on nitrogen storage and reuse in apple¹

The experiment was conducted in Beijing Agricultural University and was partially subsidized by the National Fund Committee of Nature and Science of China.

Abstract

Effects of autumn foliar application of N‐urea on N storage and reuse in young apple seedling (Malus Pumila Mill.) were studied. Foliar application of urea^‐15 N (3.5%) during autumn enhanced the retranslocation of leaf N to other plant parts and increased stored N. Foliar N sprays increased the proteolytic activities of the leaves; therefore, such activities appear to be a major mechanism of retranslocation of leaf N. Foliar applied N enabled the plant to produce more growth during the following seasons. A considerable portion of the plant total N during second and third years was attributable to the foliarly applied N during the first year.

Notes

The experiment was conducted in Beijing Agricultural University and was partially subsidized by the National Fund Committee of Nature and Science of China.

Graduate student and currently a visiting scientist under FAO (Food and Agricultural Organization of the United Nations) Fellowship at USDA‐ARS Appalachian Soil & Water Conservation Research Laboratory, Beckley, West Virginia, USA.

Professors in Beijing Agricultural University.