People always omit the organic fertilizer in soil fertilization in orange planting, and soil acidification is serious, and difference of fertilization is very large. Besides, the fertilizing time and methods are unreasonable, and the micronutrient deficiency is very common for orange plants in southern China. There are some points to be noticed:
For orange trees
1/ Pay attention to the organic fertilization, develop the orchard green manure.
2/ Fertilize the Silicon-calcium fertilizer, lime for the acid soil
3/ Optimize the dosage of N, P, K fertilizer, Fertilizer proportion and time of fertilizing, supplying the micronutrient such as Ca, Mg, S, B, Zn and so on.
4/ Using the hole application or Furrow application instead of broadcasting.
5/ Combine the fertilization and the water management as well as High yield and high quality cultivation technology, use fertigation during the arid season.
Methods of fertilizing
1/ Yield is 3000kgs/667㎡ or above: Organic fertilizer 2-4 cube/667㎡, N fertilizer（N）25-35kgs/667㎡, P fertilizer（P2O5）8-12kgs/667㎡, K fertilizer（K2O）20-30kgs/667㎡.
2/ Yield is 1500-3000kgs/667㎡: Organic fertilizer 2-4 cube/667㎡, N fertilizer（N）20-30kgs/667㎡, P fertilizer（P2O5）8-10kgs/667㎡, K fertilizer（K2O）15-25kgs/667㎡.
3/ Yield is 1500kgs/667㎡ or below: Organic fertilizer 2-3 cube/667㎡, N fertilizer（N）15-25kgs/667㎡, P fertilizer（P2O5）6-8kgs/667㎡, K fertilizer（K2O）20-30kgs/667㎡.
The orchard which lacks of Ca, Mg and S, calcium magnesium phosphate fertilizer is adopted; The orchard which is lack of Zn and B, we can fertilize 0.5-0.75kgs sodium borate, 1-1.5kgs fertilizer grade zinc sulfatepowder or zinc sulfate granular, mixed with the organic fertilizer in autumn; Orchard whose pH<5.50, use 60-80kgs/ 667㎡ or dolomite fines, 50% of which used in autumn, the other used in summer.
Fertilization in spring,: 30-40% N fertilizer, 30-40 P fertilizer, 20-30% K fertilizer fertilizing in January and February before sprouting; Fertilization in summer: 30-40% N fertilizer, 20-30% P fertilizer, 40-50% K fertilizer used in June to July; Fertilization in autumn an winter: 20-30% N fertilizer, 40-50% P fertilizer, 20-30% K fertilizer, all organic fertilizer, zinc fertilizer are fertilized in November and December.
