Table 1. General information of the Fuji apple tree orchards at Changping, Beijing.

	5-yr-old	18-yr-old	22-yr-old
Orchard size (ha)	0.33	1.67	0.33
Nitrogen application (kg N ha−1 yr−1)	135	149	149
Phosphorus application(kg P ha−1 yr−1)	135	149	149
Potassium (kg P ha−1 yr−1)	135	149	149
Animal manure (kg ha−1 yr−1)*	87000	99000	97500
KNO3 (kg ha−1 yr−1)	300	330	330
ZnSO4 (kg ha−1 yr−1)	300	330	330
Bacterial fertilizer (kg ha−1 yr−1)	300	330	330
Irrigation amount (m3 ha−1 yr−1)	3220	3300	3300

^*OM content: about 25%; nutrient content: N - 1.6%, P - 1.5% and K - 0.8%.