Gannan Navel Orange Originating from Brazil, Navel orange is a special variety of sweet orange and is a high-grade fruit in the international citrus fresh fruit market. Navel oranges are deeply loved by consumers because of their large fruits and seedless characteristics. However, navel oranges are easily threatened by pests and diseases during the cultivation process, which affects the fruit quality and reduces the economic benefits of planting. In order to ensure the quality and yield of navel oranges, a variety of efficient and reasonable cultivation and management techniques have come into being.
Since navel oranges need to go through a long-term process from cultivation to growth and fruiting, in order to improve the overall yield, it is necessary to pay attention to the growth of navel oranges from many aspects.
Navel orange cultivation techniques
Selection of garden land and variety.
The selection of navel orange plantation land should ensure that the transportation is convenient and the water source is sufficient, and the atmosphere, soil and irrigation water sources are not polluted. And the average annual temperature of the plantation should be controlled at 17 19, and the low temperature under extreme climatic conditions should also be not less than 3. At the same time, the local annual rainfall should also be guaranteed to be about 1000mm, and the relative humidity should be controlled at 60% to 75% to ensure that the plantation can have 1600h of light. For the soil conditions of the plantation, it is necessary to choose as deep and fertile soil as possible, rich in organic matter, with a soil pH of 55～6.5 within this range, and a guaranteed organic matter content of 5%. Navel orange root activity requires soil with a constant temperature of 12. Sandy loam soil should be selected for soil below 1 m in the underground environment. If it is red loam clay. The ideal cultivation environment can be achieved through improvement. Most navel orange trees are located in areas with gentle terrain and hilly slopes below 25°. The main varieties of navel orange that can be selected are Newhall, Linna, Fukumoto and other varieties, which have the characteristics of high yield, stable yield and good quality, and have good promotion and utilization value. The seedlings of navel oranges should be purchased from non-quarantine areas to ensure that the varieties of navel oranges can be pure and convenient for subsequent grafting.
Water and fertilizer technology. For the fertilization of navel orange juvenile trees, the annual fertilization should be controlled at 5 7 times, usually 7 10 days before the new shoots germinate, and when the growth is stopped and the new leaves turn green, an additional shoot fertilizer should be applied. It is best to choose a fast-acting nitrogen fertilizer for the type of fertilizer, but after August, the nitrogen fertilizer should be strictly controlled to avoid late autumn shoots. In November, a basal fertilizer should be applied according to the actual situation of the improved soil, so as to achieve nutrient accumulation and improve the cold resistance of navel orange fruit trees. For the fertilization of adult trees, a total of three times a year should be fertilized, namely fruit picking fertilizer, fruit strengthening fertilizer and shoot promotion fertilizer. The specific methods of fertilization can be selected as furrow fertilization, hole application and soil surface application. In this process, it is best to apply more organic fertilizer and make reasonable use of inorganic fertilizer. Normally, farmyard manure generally includes crop straw, compost and mud manure. From a specific point of view, rhizosphere fertilization is the direct application of organic and inorganic fertilizers to the rhizosphere soil, and the fertilization area is near the drip line of the canopy. Extra-root fertilization is to dissolve the fertilizer in water, and use the stomatal osmosis of navel orange leaves and fruit skin to absorb nutrients dissolved in water. It should be noted that the concentration of extra-root fertilization should be reasonably controlled, and application under high temperature conditions should be avoided to avoid serious fertilizer problems.
In addition, in the process of water management, navel oranges are more sensitive to moisture during the spring shoot germination and fruit expansion period, and if there is a drought problem at this stage, then it should be watered in time. Orchards where conditions permit, drip irrigation and sprinkler irrigation are also available. If conditions do not permit, methods such as furrow irrigation and irrigation should be used. In the season of heavy rainfall, it is necessary to remove the water in the orchard in time, and if the fruit encounters a rainy season before harvesting, then it is necessary to adopt scientific and effective drainage and water control methods, such as mechanical drainage and irrigation and plastic film to avoid rain.
Plastic pruning techniques.
There are also obvious differences in the pruning techniques during the cultivation and management of navel oranges.
When the young tree is young, it is necessary to wipe the buds in time, retain the main trunk, appropriately expand the crown and balance the main branches, and at the same time pay attention to the root and trunk, and ensure that it is formed at one time after proper adjustment. For pruning young trees, in addition to stubbing the main and extended branches, light pruning should be carried out as much as possible [6].
For the pruning of navel orange fruit trees that bear fruit at the beginning of fruiting, it is mainly to shorten the trunk branches to promote the development of strong autumn shoots. For the overly long vegetative branches, about 8 10 leaves should be retained, and on this basis, topping should be carried out in time, and the branch groups after fruiting should be shortened. When more vegetative branches of summer and autumn shoots are extracted, one-third of the mediocre branches and weak branches should be retained.
For the pruning of navel orange trees in the peak fruiting period, the main operation is to prune the fruiting branch group, cut off the dead branches and diseased branches in time, and renew the side branches and twigs. For the autumn shoots that are extracted in the current year, it is necessary to implement the treatment of short strength, retention in the middle and weakness to ensure that the shoots and the results can maintain a relative balance, and effectively prevent the emergence of large and small fruit problems.
From the perspective of pruning methods, the pruning methods of navel oranges in the growing period mainly include wiping, bending branches and circumferential cutting, etc., focusing on the pruning of the flower bud stage and the stubbing of summer and autumn. In this process, the weakened branch group on the periphery of the canopy should be shortened, the mediocre branch group should be retained, and the leaf branches should be preserved as much as possible to ensure that the tree can be restored in a short time. On top of this, it is necessary to cut off all the branches that retain the side branches, and pluck the new shoots as soon as they are extracted, so that they can branch and form a new crown.
Flower and fruit thinning and nutrient solution fruit preservation technology.
Loosening the branches should be carried out in the time period between fruit picking and budding, as far in advance as possible, and if it is too late, it can also be carried out during the flowering period. For dense branches, you can take the method of dividing five by two and three by one, and if the branches are more vigorous, then the strongest branches should be thinned. If they are all weak branches, the weakest branches should be removed. The flowering period is generally before the bud to the flower, as long as it is convenient to operate, the time can be as early as possible. Fruit thinning involves thinning the leafless flowers that grow densely before flowering.
Frost damage prevention technology.
In order to effectively prevent frost damage, local cultivators can choose reservoir or sedimentary orchards for cultivation, and pay attention to water and fertilizer management and pest control. On this basis, it is necessary to strictly control the amount of fruit and late autumn shoots, strengthen the tree potential, and improve the cold resistance of navel orange seedlings. In the pre-cold prevention stage, quicklime and sulfur powder are also used in winter, combined with salt and water, evenly painted on the trunk of the tree, and when the cold wave comes, it is necessary to carry out appropriate fumigation. For post-freeze treatment, for frost-damaged trees of grade 1 and 2, the leaves that have been curled by frost damage and have not fallen off can be removed in time, and the frozen dead branches can be cut off after spring budding. And fertilization should ensure fertilization with water, and additional urea and potassium dihydrogen phosphate are used for root topdressing. If it is a heavy frost tree above level 3, after the boundary between life and death is clarified, wax should be applied to the wound of the tree, and it should be strictly bandaged with nylon cloth to ensure that the frostbite wound can be protected.
In the process of growing navel oranges, it is important to choose efficient cultivation management techniques. At the same time, in order to ensure the fruit quality of navel oranges, it is necessary to control various pests and diseases to provide guarantee for the healthy growth of navel oranges. In the specific control process, agricultural technology, biotechnology and chemical technology are very common, it is necessary to check the specific situation in the navel orange orchard first, and configure the agent according to the characteristics of the disease to achieve a good pest control effect.