[Effects of different long-term fertilization patterns on Fuji apple yield, quality, and soil fertility on Weibei Dryland, Shaanxi Province of Northwest China].

A 7-year (2003-2010) located field experiment was conducted to evaluate the effects of different long-term fertilization patterns on the Fuji apple yield, quality, and soil fertility on the Weibei Dryland, Shaanxi Province of Northwest China. Seven treatments were installed, i. e., no fertilization (CK), inorganic P and K fertilization (PK), inorganic N and K fertilization (NK), inorganic N and P fertilization (NP), inorganic N, P, and K fertilization (NPK), swine manure (M), and half inorganic N, P, and K combined with half swine manure (NPKM). Each treatment had three replications. Fertilization increased the apple yield. The average yield in the 7 years under fertilization was increased by 14.4%-63.8%, as compared to the CK. The average yield decreased in the order of NPKM > NPK > or = M > NP > or = NK > PK > CK. In treatments NPKM, M, and NPK, the fruit sugar/acid (S:A) ratio, vitamin C, soluble solid, and hardness tended to be increased with time, with a smaller yearly fluctuation in treatments NPKM and M. In treatment NPKM, the S:A ratio and vitamin C increased by 30.9% and 17.5%, respectively after five years, as compared to the CK. Long-term rational fertilization increased the soil organic matter (SOC) content in 0-20 cm layer, with the largest increment in treatments NPKM and M (28.8% and 29.3%, respectively). The soil available N, P, and K contents in all layers in treatments NPK, NPKM, and M increased significantly, and the soil available N content in 0-20, 20-40, and 40-60 cm layers in treatment NPK was increased by 22.7%, 37.3%, and 53.4%, respectively. As compared to treatment NPK, the soil available P content in treatment NPKM was increased by 18.7%. In all fertilization treatments, the soil available Pcontent was significantly higher in upper layer than in lower layer.