How to Cultivate Blackberries with High Quality and Scientific Methods? Detailed Explanation of Key Technical Points

1 Site Selection

The most suitable soil texture for a blackberry orchard is loam or sandy loam. Soil pH can range from 5.0 to 8.0, but 6.0 to 6.5 is best. Soil salt content should be <0.1%, soil layer thickness should preferably be >50cm, and the groundwater level should be >100cm. For most blackberry varieties, the minimum winter temperature needs to be above -15 degrees Celsius, and the requirement is for more than 700 to 750h of low temperatures below 7.2 degrees Celsius in winter.

2 Variety Selection

Currently, varieties that perform well in the Nanjing area include Hull, Chester, Boysen, Young, TripleCrown, Navaho, Brazos and several others. When developing blackberries, the corresponding varieties should be selected according to the intended use.

3 Nursery Stock Selection

One-year-old cuttings are preferable, requiring a relatively large root system, thick and strong nursery stock, and no pests or diseases. If tip-rooted plantlets from the current year are used, plants with a good root system and relatively thick, strong growth should be selected. The size of the nursery stock should be uniform, and large and small plants should be planted separately. Nursery stock thickness: >0.5cm (ground diameter); nursery stock length: 20 to 30cm.

4 Planting and Orchard Establishment

Open planting trenches or dig planting holes. Planting trench width: 50cm, depth: 40cm; planting hole length and width: 50cm, depth: 40cm.

The best time to plant nursery stock is from early February to early March.

Base fertilizer needs to be applied when planting nursery stock. Type and amount of base fertilizer: farmyard manure is preferable, at 0.5 to 0.8m3 per mu. An organic compound fertilizer suitable for pollution-free use with an effective N, P, K content of 25% may also be used, at 50 to 60Kg per mu.

The row and plant spacing for planting nursery stock varies by variety, specifically: Hull, Chester, Brazos and TripleCrown: 250cm×150cm; Boysen and Navaho: 180 to 200cm×130 to 150cm; Young: 150 to 170cm×120 to 130cm.

The specific method of planting nursery stock: opening trenches or digging holes is best done in winter. After opening trenches or digging holes, the filling material should be placed in immediately, and soil should be backfilled to 1/2 to 2/3. During planting, the base fertilizer should be applied evenly into the trench or hole and mixed with soil, then covered with soil. The root system must not come into contact with fertilizer when planting. The planting depth should be such that the root crown of the nursery stock is planted into the soil.

Irrigation: the settling water should be watered thoroughly. If drought occurs, re-watering 2 to 3 times is needed.

A drainage and irrigation system should be established in the orchard, especially for large-scale orchard establishment. The drainage and irrigation system depends on the topography and landforms. Generally, a drainage and irrigation trench is opened every 50 to 100m in length and width, and the trench width and depth should preferably be 60 to 80cm.

5 Trellis Construction

Trellis materials and specifications: cement posts or wooden posts. Cement post specifications vary by variety, specifically: Hull, Chester, Brazos and TripleCrown: 7cm×9cm×230 to 250cm; Boysen and Navaho: 6cm×8cm×210 to 230cm; Young: 6cm×7cm×190 to 210cm. Wooden posts should be 6 to 8cm thick and 200 to 250cm long; use No. 12 to No. 14 wire.

Trellis spacing: 5 to 6m.

Trellis construction time: it can be carried out immediately after planting, and no later than the end of that year.

Wire installation: in the first year, install two wires. The first wire is 50cm to 60cm above the ground, and the second wire is 50cm from the first wire; in the second year, when pruning and tying, install a third wire, and the third wire is 50cm from the second wire.

6 Routine Management

6.1 Cultivation, Weeding and Mulching

This depends on the weed situation. Generally, cultivation and weeding are carried out 3 to 5 times per year. If conditions permit, rice straw and other crop stalks can be used to mulch the entire orchard, with a thickness of 8 to 12cm. Mulching is generally done in early spring, that is, from mid-to-late February to early March. If mulched, cultivation and weeding may not be needed throughout the year.

6.2 Fertilization

6.2.1 Topdressing

Fertilize according to the plants' condition. In vigorously growing fields, topdressing should focus mainly on phosphorus and potassium fertilizers; in fields with poor growth, more nitrogen fertilizer should be applied.

Fertilizers should mainly be quick-acting fertilizers, generally applied 3 times per year. The first fertilization is from late March to mid-April, that is, after sprouting when new shoots appear, and the fertilizer should mainly be nitrogen fertilizer; the second is in early to mid-May, that is, after fruit set during the fruit expansion period, and should mainly be nitrogen and phosphorus fertilizer or compound fertilizer; the third is in August, that is, after fruit maturity (it is best if the fruiting canes of the year have been pruned and cleared from the orchard), and should mainly be compound fertilizer.

Types and amounts of fertilizer: urea 10Kg/mu, diammonium phosphate 20Kg/mu, potassium sulfate 30 to 40Kg/mu.

Application method: trench application or hole application. After the fertilizer is applied, soil should be covered. If soil moisture is poor, topdressing should be combined with watering.

6.2.2 Winter Fertilization

In winter, open trenches for fertilization. The trench should be more than 60cm from the plants, and the trench width and depth should preferably be 20 to 30cm. The fertilizer should mainly be farmyard manure, at 1.0 to 1.5m3 per mu, or an organic compound fertilizer with an effective N, P, K content of 25% at 80 to 100Kg per mu.

6.3 Drought Resistance and Drainage

In hilly areas, drought resistance is mainly needed in summer and autumn. Generally, during drought, irrigate once every 10 days, and each irrigation should be thorough. If mulched, irrigate once every 20 days. In plains or low-lying areas, attention should be paid to drainage during the rainy season (the plum rain season in the Yangtze River Basin). Do not allow prolonged waterlogging.

6.4 Pest and Disease Control

Do a good job in pest and disease investigation, achieve early prevention and early control, and pest and disease control should be carried out in accordance with pollution-free requirements.

6.5 Pruning and Tying

Summer pinching: generally in early summer when new shoots appear and grow rapidly, pinch when the new shoots reach a height of 1.0 to 1.2m. After pinching, the new shoots should be fixed to the wire.

Removing dead canes after fruiting: generally in July and August (varies among varieties), remove the previous year's new shoots and side branches from the base. After cutting off dead branches, they should be cleared from the blackberry orchard.

Winter shaping and pruning: carry out from early December to early February. The pruning points are as follows: (1) Cut off dead branches and branches damaged by pests and diseases; (2) Thin out weak and overly dense branches; (3) Shorten the remaining healthy and full branches; (4) Evenly tie the pruned branches to the wire. Generally, keep 8 to 12 thick and strong branches per plant, with an average length of 100 to 120cm.

Tying: after shaping and pruning, the canes should immediately be guided and tied to the wire. Each branch needs to be spread out separately, and multiple branches must never be tied together.

6.6 Fruit Harvesting

Blackberry berries do not ripen uniformly, so they must be harvested in batches, generally once every 2 to 3 days. The most obvious sign of blackberry fruit maturity is coloration on the berry surface. The fruit surface gradually turns from the initial green to red, and finally becomes black and glossy. Blackberry harvesting depends on the use, transport distance and conditions. Usually, for sale as fresh fruit, harvest at 90% maturity; when the transport distance is long or for canning, harvest at 80% maturity; when the fruit is used for processing fruit wine, juice or jam, harvest when fully ripe.