[Effects of balanced fertilization on growth and fruit quality of 'Huang-guan' pear on desert area.]

A field experiment was carried out to study the effects of balanced fertilization on growth and development, yield, fruit quality and mineral content in 'Huang-guan' pear to provide a theoretical basis for the reasonable level of fertilization in pear orchards. Four treatments were arranged with 12-year old 'Huang-guan' pear trees from the same orchard: conventional fertilization (CK), low levels of N, P2 O5 and high level of S (T1 ), medium levels of N, P2 O5 and S (T2 ), high levels of N, P2 O5 and low level of S (T3 ). The results showed that different treatments had little effect on the growth and development of current-year branch and leaves in the first year. However, in the se-cond year, T1 treatment promoted the length and diameter of current-year branch by 16.2% and 11.4%, respectively. Continuous fertilization could increase the leaf mineral contents in different degrees. The contents of Cu, Fe, and Zn in leaves under T1 treatment, Mg and B in leaves under T2 treatment, and P and Mn in leaves under T3 treatment were highest. Different fertilization levels had no significant effect on yield but on fruit quality. The contents of soluble sugars and vitamin C (Vc) were significantly increased by T2 treatment, which was 4.2% and 7.1% higher than those in CK. However, T1 significantly decreased contents of total soluble solid, soluble sugars and Vc, while highest organic acid content presented in T3 . Fruit Fe content was positively correlated with soluble sugar content and fruit shape index, but was negatively correlated with single fruit mass, organic acids and Vc. Fruit P content was positively correlated with fruit shape index and firmness, but was negatively correlated with contents of soluble sugars, organic acids and Vc. Accordingly, T2 could improve fruit quality and maintain the productivity, and thus should be the suitable fertilization strategy for the 'Huang-guan' pear management in desert area.