Effects of N application rates on growth, nutrient accumulation and translocation of Xanthoceras sorbifolia

In an effort to determine the optimal nitrogen application rate for Xanthoceras sorbifolia, a series of field trials were conducted to investigate the effects of different nitrogen application rates on the growth, nutrient accumulation and translocation in this species. Five nitrogen application levels of 0 (N0 ), 130 (N1), 180 (N2), 230 (N3) and 280 (N4) mg/seedling were set up with five replications. Fertilizer in the form of urea was applied once a week and 12 times throughout a single growing season; the amount of fertilizer was the same in each nitrogen application. The results indicated that different nitrogen application rates significantly affected biomass and nutrition accumulation rates at different stages of growth in this species. The order of accumulation of nitrogen, phosphorus and potassium throughout the entire growing season was N K P. Nitrogen application rates affected the translocation efficiency and distribution ratio of nitrogen, phosphorus and potassium in different organs. The highest translocation efficiency was found in N3. The order of accumulation efficiency of nitrogen, phosphorus and potassium was N P K. Nitrogen, phosphorus and potassium nutrients mainly concentrated in the roots and leaves during the later stages of growth. Under the experimental conditions used here, the recommended nitrogen application rate for X. sorbifolia is 230 mg/seedling.