Post-harvest Field Management Methods and Pruning Precautions for Mango
Do you know about Taiwan mango and native mango? According to the cultivation calendar for the Taiwan region, the mango harvest season is about May to October. During this period, the farmers' hard work of the whole year finally pays off. However, the 1 to 2 months immediately after harvest are a critical period for future mango production.
For a mango plant that has reached fruiting age, in terms of the yield of a single plant, the Irwin variety produces about 60 kg or more, Jinhuang produces about 50 kg, and the yields of other varieties are roughly between these amounts. Heavy fruiting consumes a considerable amount of nutrients for the mango tree, and this does not even include the waste caused by flower drop and fruit drop during flowering and the young fruit stage. Therefore, the first problem encountered after mango harvest is excessive nutrient consumption. If the tree's nutrients are not replenished in time, it can easily cause the tree to weaken and age, which in turn invites pests and diseases, shortens the tree's lifespan, and reduces harvest yields, resulting in aftereffects such as poor overall economic benefits for the orchard. In order to produce large amounts of nutrients (especially carbohydrates) for the growth of next year's fruit, first of all, the aboveground part must have enough shoots and leaves to carry out photosynthesis; secondly, the underground part must have a sound root system and be supplied with sufficient mineral elements and water to facilitate absorption. Furthermore, given the physiological and biochemical characteristics of mango, the post-harvest period coincides with the period of mango shoot growth and flower bud differentiation. Only with mature and strong shoots can there be good flower bud differentiation, and only then can there be excellent yield and quality next year. Therefore, there are two stages of work at this time:
1. The work in the first half is a continuation of the management work during the fruiting period, mainly to promote the formation of new shoots. Therefore, the most important work at this time is shoot management, soil fertilization, and water management. During the fruiting period, because of fruit growth, most shoots and leaves age due to excessive nutrient consumption, and their photosynthetic efficiency is relatively low. As fruiting branches for next year, their fruit production quality is poor. A general reorganization of the shoots is necessary to cultivate new shoots anew. The number and quality of new shoots can determine the quality and quantity of next year's fruit. Pruning stimulates the formation of new shoots, increasing fruiting branches and thus increasing yield; in addition, shoots that sprout during the fruiting period have already caused the tree shape to become disordered due to the downward pressure of the fruit's weight. Pruning can restore the tree shape to facilitate ventilation and light penetration and make other field management operations convenient. Fertilization and water management can promote vigorous shoot growth and improve fruit quality.
2. The work in the second half is to cultivate and maintain mature, well-developed fruiting branches. The period of mango flower bud differentiation is during the transition from autumn to winter. Because new shoot growth takes time, the growth of one flush of shoots takes about 3-6 weeks, and the leaves carried on the shoots average 15. The nutrients required for the growth of one high-quality mango fruit need to be supplied by 25 leaves. Cultivating 2 flushes of shoots takes 6-10 weeks, and there is also a pause period between flushes. Therefore, pruning should be done before mid-September, and it is best to begin immediately after harvest. In this way, the development of shoots can be completed before late November, allowing time for the shoots to grow. Otherwise, if shoot development is too late and not sufficiently substantial and mature, the time for flower bud differentiation will be insufficient, which will affect next year's flowering and fruiting. Therefore, during this period, water supply should be reduced to promote shoot maturity, and pest and disease control should be strengthened to maintain sound shoots.
The following points should be noted when pruning:
1. For the pruning back of short fruiting branches, the method is to cut the fruiting branch back by 1 to 2 flushes of shoots, with the cutting position below the node between flushes.
2. When the fruiting branches of the previous year are relatively long, especially fruiting branches formed by water sprouts, cut off the green part of the branch and retain about 2 flushes of shoots down to the brown part (about 30 cm). However, do not cut back excessively, because the basal buds are too aged, and after sprouting, the proportion of deformed shoots is higher, which will affect the quality of heading and flowering next year.
3. Cut off some of the curved and drooping parts so that the angle between the new shoots and the fruiting mother branches will not be too small and form a blind spot in management.
4. Weak branches, diseased branches, overly dense branches, or excessively thick water sprouts should all be cut off as well.
5. Renewal pruning, that is, some overly old branches must be cut off to facilitate the recultivation of fruiting mother branches.
6. In mid-to-late December, before flower spikes have emerged, thinning pruning should be carried out once to remove overly dense or overly thin shoots within the canopy in order to maintain good spatial distribution.
7. For varieties such as Irwin and Tainong No. 1, after long-term pruning, the tree shape has already been set, and there are not many water sprouts; most only require pruning back. For vigorously growing varieties such as Jinhuang, Keitt, and local varieties, in addition to pruning back, there are more branches to prune, and after harvest, when new shoots emerge, girdling can also be carried out to suppress tree shape disorder caused by vegetative growth.
