Abstract:

We addressed the optimal N, P and K application rates to gain the maximum biomass accumulation of apple container seedlings by comparison of growth distinctions of their different application rates. We also designed 24 different combinations of N, P and K nutrients treatment with three factors five levels quadratic orthogonal rotation design with oneyear living apple container seedlings as experimental subjects.Results show that different N, P and K application rates have significant(P<0.05) or extremely significant (P<0.01) effects on the growth characters of apple container seedlings. We constructed a regressive model between N, P and K application rates and biomass accumulation of apple container seedlings with SPSS19.0 as a statistical analysis tool. Analysis results demonstrate that N, P and K application rates all have positive effects on the biomass accumulation of apple container seedlings with an order of x_N>x_K>x_P.However, the interactions among N,P,K application rates all display negative effects by an order of x_Nx_K>x_Nx_P>x_Px_K.Application rate of N has positive effect, but the interactions between N and K application rate and excessive application of P and K cause negative effects on the growth of apple container seedlings. Optimal application rate of N, P₂O₅ and K₂O are respectively 43.33 mg/L,28.28 mg/L and 93.94 mg/L,based on which the total biomass of apple container seedlings can attain the theoretical maximum of 94.334 g/plant.

Key words: application rate, biomass, apple container seedling, growth characters, regression model