How to cultivate and manage pomelo for a high yield? Detailed explanation of the key technical points
Pomelo (scientific name: Citrus maxima), also known as Wendan, Xiangluan, Zhuluan, Neizi and so on. It is the mature fruit of the rutaceous plant pomelo, produced in the southern regions of China such as Fujian, Jiangxi, Hunan, Guangdong, Guangxi, Zhejiang and Sichuan. The pomelo is delicately fragrant, sweet and sour, cool and moistening, rich in nutrients, and of very high medicinal value; it is one of the fruits people love to eat, and is also recognized by the medical community as the fruit with the greatest dietary-therapy effect. Pomelo tea and pomelo peel also have practical value, and can be used as medicine.
1. Strengthen the shoots, promote the shoots to turn green
For vigorous trees, when the spring shoots are 4-7 cm long, spray 15% paclobutrazol at 600 times dilution, to make the spring shoots short and sturdy and the flower clusters robust; at the leaf-unfolding stage of the spring shoots, spray the canopy with Lufenwei to promote the leaves to turn green.
2. Plastic film mulching, retain moisture and lower temperature
In summer and autumn the temperature is high and soil moisture evaporation is large, so mulch between the orchard rows with plastic film or interplant low-growing vegetables, peanuts or leguminous crops as cover. Mulching in the high-temperature summer drought retains moisture, suppresses the growth of weeds, is favorable for the growth and greening of the pomelo trees, raises the pomelo yield, and increases the economic benefits of the pomelo orchard.
3. Timely pollination, increase the full fruit set
1. Hand pollination Choose fine sunny weather, pick the fully opened male flowers of the pomelo trees, wrap the pollen in white paper, put it into a cloth bag and tie it around a person's waist against the bare skin for a full circle; after 24 hours take out the pollen, add 0.1% borax and mix, then use a brush or cotton swab to dab it onto the pomelo flower stigmas.
2. Insect pollination Mix 0.2% urea plus 0.3% granulated sugar plus 1.2% honey plus 98% clear water, and on sunny days at 8-10 am and 3-4 pm use a miniature sprayer to spray the pomelo flower stigmas, spraying continuously 2-3 times, to attract bees for pollination and increase fruit set.
4. Timely fruit thinning
When the young fruits grow to the size of a pea, carry out the 1st fruit thinning, mainly removing small fruits, diseased and insect-damaged fruits, and deformed fruits. Generally, according to 1-1.5 times the bearing capacity of the tree's vigor; when the fruits grow to the size of a thumb, carry out the 2nd fruit thinning; at this time the fruit thinning requires that the retained fruits be uniform in size and evenly distributed.
5. Transplanting young fruits
When the pomelo fruits grow to the size of an egg, cut off the overly dense young fruits or twin fruits and graft them onto branch orders that bear few fruits, so that the nutrient supply is sufficient, the fruits grow large, and the yield increases.
6. Protecting flowers and fruits
At the flower bud stage, spray the canopy with 0.1% Lufenwei foliar fertilizer plus 0.1% borax, plus 0.2% ammonium molybdate plus 0.2% monopotassium phosphate plus 0.3% urea mixed, spraying the canopy 2 times (once every 7 days); when 3/4 of the flowers have faded, use 1 bag of fruit-setting agent plus gibberellin 20 X 10-6, first dissolved in alcohol, then spray the canopy; at the physiological fruit-drop stage, use cytokinin (BA) 1 gram dissolved in alcohol and made up with water to 200 X 10-6, and from mid-April to early May apply it once to the fruit stalk, then from late May to mid-June apply it to the fruit stalk once more.
7. Do a good job of pest and disease control
1. Control of the citrus blossom midge At the peak emergence period of adults after rain, apply per mu 3% carbofuran granules 0.8 kg mixed with 25 kg river sand and broadcast on the ground. Spray the canopy 1-2 times with 90% trichlorfon (or 80% dichlorvos emulsion) at 600 times dilution. Manually remove the damaged flower buds in time, blanch them in boiling water and bury them deep.
2. Control of arrowhead scale and cottony cushion scale At the peak hatching period of the 1st generation of young scales in early to mid-May, spray the washing-powder-diesel mixture 1-2 times; the washing-powder-diesel mixture (washing powder 0.5 part plus diesel 1 part) is prepared as an 80-100 times solution, or 40% Suposa emulsion at 1500-2000 times solution, used alternately.
3. Control of red and yellow spider mites Use 5% Hexythiazox at 2000 times plus 40% isocarbophos at 800 times solution, or Omite at 2000 times solution plus a small amount of diesel mixed, to spray the canopy 1-2 times.
4. Winter trunk painting Use quicklime 6 kg, plus lime-sulfur mixture stock solution 1 kg, plus salt 1 kg, plus omethoate 50 grams, mixed with 15 kg water to paint the main trunk of the pomelo trees, to control diseases and common pests.
8. Strengthen fertilizer and water management
During the tending period of young trees, vegetative growth is dominant, to cultivate a canopy that fruits early and abundantly. Therefore, each year before and after the spring, summer and autumn shoots, apply 1 shoot-promoting fertilizer and 1 shoot-strengthening fertilizer respectively; per plant apply 5-8 kg farmyard manure plus 0.1-0.2 kg urea mixed in. After entering the fruiting stage, generally in early to mid-February apply a light spring fertilizer, per plant applying 50 kg farmyard manure plus 0.3-0.4 kg urea. In mid-May skillfully apply a fruit-stabilizing fertilizer, per plant applying 0.1% Lufenwei foliar fertilizer 1-2 times, or 0.2% monopotassium phosphate and 0.3% urea mixed as a root-outside top dressing. In mid-July heavily apply a fruit-strengthening and shoot-promoting fertilizer, per plant applying 60 kg farmyard manure plus 1 kg superphosphate and 2 kg plant ash mixed in. In mid to late September apply deep a post-harvest send-off fertilizer (also called rejuvenation fertilizer), per plant applying 60 kg farmyard manure plus 1 kg oil cake fertilizer mixed in, to restore tree vigor.
9. Do a good job of shaping and pruning
1. Timely pinching When the spring and summer shoots have grown to about 30 cm in length, pinch them in time, and thin out the excess buds.
2. Branch training and shaping In autumn, for strong vigorous trees, adopt measures such as propping, pulling and hanging to increase the opening angle, ease the growth vigor, and promote early fruiting.
3. Ring cutting to promote flowering In late September, use a sharp small knife to make 3 staggered ring cuts on the side branches, blocking the downward transport of nutrients made by the leaves, increasing the accumulation of organic nutrients in the leaves, and effectively increasing the flower quantity of the following year.
4. Control late autumn shoots and winter shoots Late autumn shoots and winter shoots that emerge after early November will consume a large amount of nutrients, which is not favorable for the differentiation of flower buds on the fruiting mother branches of the next year. When the autumn shoot leaves turn green and mature, spray the inhibitor paclobutrazol at 300 times 1-2 times, which can effectively avoid the sprouting of winter shoots.
5. Pruning and thinning branches After harvesting the fruit, thin out 1-2 vigorous long large branches in the middle and upper part of the canopy, to enhance light penetration into the inner canopy. In pruning, grasp the principle of heavy at the top and light at the bottom, heavy outside and light inside; thin out more and cut back less, prune moderately, cutting off overlapping branches, crossed branches, diseased and insect-damaged branches, competing branches, dead and dry branches and fruit stalks; for clustered branches, thin out one of three, two of five, so that the branches are evenly distributed, and retain as far as possible the lateral branches, short fruit branches, lower leafless branches and drooping branches in the inner canopy, so that the canopy is ventilated and lets light through, achieving consecutive years of high and stable yield.
10. Timely harvesting
Generally harvesting in late November is appropriate; choose sunny days for picking, and during harvesting, transport and storage, handle gently. For storage and freshness preservation, you can use a 2,4-D plus carbendazim solution to wash the fruits for sterilization, then pack them individually in freshness-preserving bags for storage.