Abstract:
15N tracer elements were used to study the effects of fertilization either using a fertilizer applicator or broadcast application in the radial ditch (CK) on nitrogen absorption, utilization, and distribution, and fruit quality and yield of five-year-old trees of the early-maturing peach Yuhualu and ten-year-old trees of the late-maturing cultivar Chinese Peach. After fertilization with the fertilizer applicator, the percentage nitrogen derived from fertilizer (Ndff%) of new shoot leaves increased significantly from the new shoot growth stage and throughout the growing season the Ndff% and chlorophyll content of new shoot leaves were maintained at high levels, while the growth rate of new shoots was accelerated significantly at the new shoot growth stage. After the fruits were harvested, the Ndff% of the fruit flesh and stone were 3.64 and 4.73 times higher, respectively, than those of CK. The nitrogen absorptivity of the plant was 20.35% at the end of the growing season, which increased 5.87 percentage points than that of CK. These results indicated nitrogen was absorbed more quickly and transported to newly developing organs following fertilization with the fertilizer applicator and, in addition, nitrogen utilization efficiency was significantly improved. After fertilization with the fertilizer applicator, the percentage residual nitrogen fertilizer was 49.33%, whereas with broadcast fertilization in the radial ditch, the residual nitrogen fertilizer was 50.46%; the difference between the two methods was not significant. Fertilization with the fertilizer applicator was beneficial to improve yield and the soluble solids content of peach fruit. Provided with 1000 kg/hm2 compound fertilizer applied with the fertilizer applicator each year, the soluble solids of peach fruit was 14.14% and the fruit yield was 26 780 kg/ha, respectively, an increase of 3.31 percentage points and 3525 kg/ha over that of CK (1250 kg/ha).