Abstract:

Biomass, nutrients (N, P, K) content dynamics and nutrient load of Padus maackii one-year-old bare-root seedlings were studied under conventional (CF), exponential (EF) and doubled exponential fertilization (DEF) regimes. 1) At the end of the growing season, the biomass accumulation of seedlings was 37.00 g·stem^-1 and 35.60 g·stem^-1 under EF and DEF treatment, respectively, and they were 36.5% and 31.3% greater than that with CF treatment (P<0.05); 2) From the 9^th to 11^th weeks, the fast-growing periods of seedlings, N content increment of seedlings was 0.28 mg·stem^-1 and 0.17 mg·stem^-1 under EF and DEF treatment, respectively, and they were significantly higher than that with CF treatment (0.03 mg·stem^-1) (P<0.05); 3) N load of seedlings under EF (0.69 g·stem^-1) and DEF (0.73 g·stem^-1) treatments were significantly greater than that with CF treatment (0.44 g·stem^-1) (P<0.05); 4) N exponential fertilization (EF, DEF) improved P and K uptake by seedlings (DEF>EF>CF). At the end of the growing season, P mass fraction in seedlings was 28.4% and 9.0% greater under EF and DEF treatments than that with CF treatment (P<0.05); K mass fraction in seedlings was 12.5% and 19.9% higher under EF and DEF than that with CF treatment (P<0.05). Exponential fertilization regimes effectively promoted biomass accumulation and improved nutrient loading in P. maackii seedlings. Outplanting,meanwhile, results so far indicate the seedlings with exponential fertilization had higher survival rate and better growth performance than CF seedlings when outplanted.

Key words: Padus maackii, exponential fertilization, biomass, N nutrient loading