How to Fertilize Pomelo? Master the Methods and Key Timing Points

SummaryFertilization methods: Pomelo is generally fertilized through the soil; for young trees, ring and dish methods can be used, while for mature trees, trench, radial trench, hole application, and whole-orchard application can be used; for foliar supplementary feeding, leaf spraying can be done. Fertilization timing for young trees: For young trees 1-3 years after planting, quick-acting fertilizer can be applied from March to August, and decomposed manure, compost, oil cake, etc. can be applied in October. Fertilization timing for mature trees: Mature trees can be given quick-acting fertilizer before bud break.

I. Pomelo Fertilization Methods

1. Soil fertilization

Young trees can be fertilized using ring and dish methods, while mature trees can be fertilized using trench, radial trench, hole application, whole-orchard application, etc.

2. Foliar supplementary feeding

(1) Besides soil fertilization, pomelo can also be given leaf spraying. Foliar feeding absorbs nutrients through the stomata. This method uses less fertilizer and gives relatively good results, but it cannot replace soil fertilization. Spraying is best done when new shoots are changing color and during the young fruit stage, and the undersides of the leaves can be emphasized.

(2) During high summer temperatures, foliar supplementary feeding can be done on sunny days, generally before 10 a.m. after the dew has dried and after 4 p.m., when the temperature is 18-24°C.

(3) The concentrations of various fertilizers are urea 0.2%-0.5%, clear urine 5%, zinc oxide 0.2%, boron 0.1%-0.2%, ammonium molybdate 0.2%, ferric citrate 0.1%-0.2%, magnesium nitrate 0.5%, potassium nitrate 0.3%-0.5%, potassium sulfate 0.1%-0.3%+0.2% slaked lime, monopotassium phosphate 0.2%-0.4%, superphosphate extract 1%, zinc sulfate 0.1%-0.2%+0.1% slaked lime, magnesium sulfate 0.2%-0.4%+0.2% slaked lime, manganese sulfate 0.1%+0.1% slaked lime.

II. Fertilization Timing for Young Trees

1. For young trees 1-3 years after planting, the main goals are to develop a strong root system, promote the emergence of new shoots, form a canopy as quickly as possible, and enter the fruiting stage early. During this period, nitrogen, phosphorus, and potassium fertilizers can be applied. Because young trees have few and weak roots, a shallow distribution, and weak absorption capacity, they need small amounts applied more frequently.

2. From March to August, a quick-acting fertilizer can be applied once every 15-20 days, which helps promote the growth of the three flushes of new shoots in spring, summer, and autumn. About 20 days before each flush, apply 1-2 applications of shoot-promoting fertilizer; after the flush emerges and the new leaves begin to turn green, apply fertilizer once more, which helps promote the maturation of the new shoots.

3. Generally after mid-September, quick-acting nitrogen fertilizer should not be applied, to avoid the emergence of late-autumn shoots. In October, a base fertilizer can be applied once, mainly decomposed manure, compost, oil cake, etc. Each tree can be given 25-30 kg of decomposed pig and cattle pen manure, or 1-1.5 kg of cake fertilizer, which helps strengthen the tree vigor and improve the plant's resistance.

III. Fertilization Timing for Mature Trees

1. The fruiting mother branches of mature trees are mainly spring shoots. Quick-acting fertilizer can be applied before bud break, which helps promote spring shoot growth, keep old leaves functioning vigorously and delay leaf drop, increase the nitrogen content of the leaves, ensure complete flower organ development, and form leafy fruiting branches to strengthen shoots and flowers. Fertilization can be done 20-30 days before bud break.

2. For trees in an on-year, in order to thin excessive flowers and increase the number of vegetative shoots, spring fertilizer can generally be delayed until the summer flowering period, and the amount of nitrogen fertilizer can be appropriately increased during this time. For trees in an off-year, it can be moved earlier to early spring, and the amount of fertilizer should not be too much, which helps control excessive vegetative shoot growth and improve the fruit-setting rate. Pre-flowering fertilizer can include nitrogen, potassium, and phosphorus fertilizers, with the amount applied accounting for about 20% of the total annual fertilizer application.