A Comprehensive Analysis of Key Kiwifruit Cultivation Techniques
Kiwifruit belongs to the genus Actinidia in the family Actinidiaceae. It is a deciduous climbing vine fruit tree, rich in various vitamins and nutrients, known as the "king of fruits," and holds high economic and cultivation value. It is suitable for growing in mild climates with abundant rainfall, fertile soil, and lush vegetation, in deep, well-drained, moderately moist black humus soil or sandy loam with a pH of 5.5-7 (slightly acidic soil)...
Kiwifruit belongs to the genus Actinidia in the family Actinidiaceae. It is a deciduous climbing vine fruit tree, rich in various vitamins and nutrients, known as the "king of fruits," and holds high economic and cultivation value. It is suitable for planting in locations with a mild climate, abundant rainfall, fertile soil, and lush vegetation, in deep, well-drained, moderately moist black humus soil or sandy loam with a pH of 5.5-7 (slightly acidic soil).
I. Selecting Suitable Varieties
Mainly Hongyang (red-fleshed), Hayward, Bruno, Qingcheng No. 1, Qinmei, Miliang No. 1, Chuanmi No. 2, Chuanmi No. 3, Chuanmi No. 4, etc.
II. Seedling Propagation
1. Rootstock Seedling Cultivation
Collect fully mature fruit from early September to early-to-mid October. After the fruit ripens and softens, squeeze out the fruit together with the seeds, put them into a gauze bag and rub them so that the seeds separate from the flesh, then rinse repeatedly with clean water, spread the washed seeds indoors to dry in the shade. Soak the seeds in warm water at 40-50°C for 2 hours, then soak in cold water for a full day and night, then stratify in sand for 50-60 days before sowing. During sand stratification, kiwifruit seeds are sensitive to both drying out and excess moisture, so check and turn them frequently to prevent mold. The ideal sowing time is generally mid-March to early April. First, select a nursery site with deep, fertile soil and good drainage, irrigation, and transportation conditions; second, prepare the land and make beds, apply sufficient base fertilizer, clear debris, make beds about 1 m wide, press the seedbed down lightly, water thoroughly, and sow the sand-stratified seeds together with the sand. After sowing, spread a layer of fine river sand about 2-3 mm thick, cover with rice straw, and spray water on the straw or set up a small plastic (11410, 25.00, 0.22%) tunnel. Third, strengthen seedbed management to ensure the cultivation of robust rootstock seedlings.
2. Grafted Seedling Cultivation
The grafting period is best about 20 days before bud break, mainly using methods such as single-bud cut grafting. Select scions that are plump and have a small pith, cut a branch segment with one bud, 3-4 cm long. Choose a flat side and cut away the bark layer, with the cut surface ideally 2-3 cm long and deep enough to expose the xylem or slightly include the xylem, then cut a short slanted surface of about 50 degrees on the opposite side of the cut surface. Cut the rootstock at 10-15 cm above the ground, choose a smooth side and make a downward cut, with the cut surface slightly longer than the scion cut surface and the same depth as the scion, peeling back 2/3 of the rootstock bark; then insert the scion, ensuring the scion and rootstock are roughly the same size; make sure the cambium layers of rootstock and scion are aligned, then wrap with plastic grafting film, leaving the scion bud eye exposed.
Three to four weeks after grafting, the grafted buds begin to sprout. Once the new shoots have grown and basically hardened, the binding film can be removed. For spring and autumn side-grafted seedlings that have survived, cut the rootstock immediately, with the cut about 4 cm from the graft union. For summer grafted buds that survive, the rootstock can first be bent and then cut. Promptly removing sprouts on the rootstock is key to survival and shoot growth. The nursery land should be cultivated and weeded frequently, taking care not to touch the newly emerged grafted buds during weeding. After the grafted buds sprout and grow shoots, a support stake should be set up beside the grafted bud, and the new shoot should be tied to the stake. When seedlings reach 60 cm in height, they should be appropriately pinched back. Combined with irrigation, human manure, pig manure, etc. can be applied, or 1% urea can be added to the water; when fertilizing in July, an appropriate amount of superphosphate can be added to promote hardening of the seedling branches and plump bud eyes. From July to August, kiwifruit seedlings should be shaded, avoiding direct strong light.
III. Orchard Construction 1. Orchard Site Selection
The kiwifruit root system is fleshy and particularly fragile; it fears both waterlogging and high-temperature drought, and new shoots fear both being broken by strong winds and damage from late spring cold or low-temperature freezing. It is suitable for planting in sub-alpine areas (800-1400 m above sea level). Choose a site with deep soil, fertile soil, loose texture, good drainage, and convenient transportation to establish the orchard. If cultivating kiwifruit in low hills, hills, or plains, appropriate drainage and irrigation facilities must be in place to ensure no waterlogging during the rainy season and timely irrigation during the dry season. It is best to establish a windbreak forest around the orchard.
2. Planting Time
In southern production areas, the best planting time is after kiwifruit leaf fall and before kiwifruit bud break the following early spring, that is, from early December to early-to-mid February, and the earlier the better.
3. Arrangement of Pollinator Trees
Kiwifruit is a dioecious fruit tree. The selection and arrangement of pollinator male plants is one of the conditions for ensuring normal fruiting. When selecting male plants, attention should be paid to those with the same or slightly earlier flowering period as the main cultivar, a large amount of pollen, and a long flowering period. The ratio of female to male plants is 6:1 or 5:1, giving high yield and good quality.
4. Planting Density
Generally, planting density is closely related to the training system. For the hedge system, the density is 2 m x 4 m; for the T-bar system, the planting density is 3 m x 4 m, about 56 plants per mu; for the flat trellis system, the planting density is 3 m x 5 m.
5. Support Structure Establishment
Generally, the support structure is set up in the winter of the same year after planting. It consists of posts (concrete posts, wooden posts, stone posts, bamboo posts, and companion trees, etc.), crossbeams (concrete posts, wooden posts, bamboo, and metal, etc.), and the trellis surface made of wire, etc. According to local conditions, choose wooden trellises, steel trellises, concrete trellises, and companion tree trellises, etc. The main training systems are the "Y" trellis and "T" trellis.
6. Planting Training Systems
There are 3 commonly used training systems in kiwifruit production: the hedge trellis, the T-bar trellis, and the flat trellis. Hedge trellis: posts are 2.6 m long and 12 cm thick, buried 80 cm in the soil, with a net height above ground of 1.8 m. On the trellis surface, 4 rust-proof wires are stretched from bottom to top, with the first wire 60 cm above the ground. A post is set every 8 m, and canes are tied to the trellis wires. T-bar trellis: a horizontal crossbeam is set at the top of the upright post, forming a small T-shaped support. The post is 2.8 m long in total, the crossbeam is 1.5 m long in total, and 3 high-strength rust-proof wires are stretched on the crossbeam. The post is buried 80 cm deep, with a net height above ground of 2 m, and a post is set every 6 m. Flat trellis: the trellis height is 2 m, with a post every 6 m, and the posts throughout the orchard can be arranged in a square pattern. The post is 2.8 m long in total and buried 80 cm. The posts around the trellis are connected with angle steel or rebar, and wires of various thicknesses are stretched between the posts to form a grid, constituting a flat trellis.
IV. Pest and Disease Control
The main pests and diseases include blossom blight, anthracnose, stem wilt, brown spot, fruit soft rot, Phytophthora disease, root rot, and pests such as scarab beetles, clearwing moths, flower bud maggots, and fruit-sucking noctuid moths. Comprehensive control methods should be adopted, focusing on strengthening management, enhancing tree vigor, strengthening soil disinfection, and emphasizing prevention. In addition, fruit sunscald is mainly managed by strengthening tree vigor management and reasonable pruning. During the fruit growth and development period (late August), bagging can be used to prevent sunscald.