Cultivation Experience of Dwarfing and Close Planting of Pomegranate in Mountainous Areas

When pomegranates are planted in mountainous areas, by adopting a series of dwarfing and close-planting cultivation measures, it is possible to achieve a small number of plants flowering in the 2nd year after planting, a per-mu yield of 415 kg in the 3rd year, and a yield of 718 kg in the 4th year, increasing the per-mu yield by 1.3 times compared with traditional cultivation. The main cultivation points:

(1) Land preparation and planting

According to the site conditions, management level and the growth characteristics of the pomegranate tree itself, choose a spacing of 2 m × 3 m between plants and rows for planting. Before planting, deep plow and improve the soil. On steep slopes, dig fish-scale pits; on gentle slopes, build reverse-slope terraces with a width of 2-3 m. When planting, dig a 1 cubic meter pit along the inner side of the terrace, and apply 5000 kg of farmyard manure or 60-80 kg of compound fertilizer per mu in the pits. Plant when the spring soil moisture is good, firm the soil after planting, water thoroughly to settle the roots, and then cover the tree base with plastic film. On arid and barren mountain land, a trunk 5-10 cm high may be retained, and planting may be done by truncating the trunk to prevent water evaporation and ensure the survival rate.

(2) Promote rapid growth and formation of young trees

1. Training and pruning. After the seedlings are planted, keep one trunk per pit and train it into an open-center layered shape. The first layer of main branches is 30 cm above the ground, all branches and buds below the training zone are removed, and clustered water sprouts sprouting from the root crown are promptly removed, opening the angle of the main branches to 50-70 degrees. Properly thin out upright water sprouts inside the canopy, overlapping and crossing branches, and weak drooping branches, so that the tree body is short and compact, and the branch tips are evenly distributed, achieving the goals of ventilation and light penetration and three-dimensional fruiting.

2. Strengthen fertilizer and water management. Apply sufficient base fertilizer when planting seedlings. Where it is inconvenient to apply base fertilizer, a 0.3%-0.5% urea solution may be sprayed on the leaves during the rapid growth period of new shoots after planting, once every 10-15 days, for 2-3 consecutive sprays. Thereafter, every autumn and winter, in combination with deep plowing of the soil, dig a ring-shaped trench 30-50 cm deep 1 m around the trunk, fill it with straw and weeds, then cover with soil and level it, to improve the soil and increase the soil organic matter content.

3. Cultivation and weeding, and rational intercropping. Before freezing each year, after thawing, and during the growing season, carry out shallow digging in the orchard to a depth of 10-20 cm, 3-5 times a year, keeping the soil surface loose and free of weeds. Peanuts, sweet potatoes, melons and other short-statured crops with a short growing period may also be intercropped between the fruit tree rows, so as to cover the ground, preserve moisture and prevent weeds, and achieve the purpose of supporting long-term income with short-term crops and increasing income efficiently.

(3) Chemical canopy control, promoting flower bud differentiation, and increasing fruit set rate

One important reason for the low yield of pomegranate is the large number of abortive flowers and the low fruit set rate. The main reason causing massive abortion of pomegranate flowers is insufficient nutrient supply during the flowering period. Adopting chemical canopy control to inhibit excessive growth of new shoots can not only save nutrients and meet the needs of flower bud development, but also control the canopy and keep it stable within a certain size and volume. According to experiments, the following methods are relatively effective.

1. Paclobutrazol soil treatment. From leaf fall to 1 month before sprouting the following year (around January 20), for 2-4 year old trees, apply 0.5-1.0 g of the active ingredient paclobutrazol per tree in 2 L of water to the roots.

2. Foliar spraying of paclobutrazol. From late April to early May each year during the pomegranate bud stage, spray the leaves with a 1000-1500 mg/kg paclobutrazol solution until the leaves drip. It is best to choose after 4 p.m. on a sunny day or a windless cloudy day; if rain occurs within 48 hours after spraying, spray once again.

3. Foliar spraying of ethephon. The time and method are the same as for foliar spraying of paclobutrazol, and the suitable concentration is 80-100 mg/kg.

Among the above 3 treatments, soil application of paclobutrazol has a relatively stable effect; ethephon can cause pomegranate leaf drop and scorched shoot tips, so the spray concentration must be strictly controlled.

(4) Strengthening flowers and preserving fruit

An important reason why pomegranate flowers do not set fruit is insufficient nutrient supply. In addition to chemical canopy control, heavy application of fertilizer to strengthen fruit and preserve flowers should also be carried out (in early to mid-April, apply 0.2 kg of potassium chloride and 0.5 kg of compound fertilizer per tree), and attention should be paid to controlling peach fruit borer, yellow slug moth, pomegranate stem window moth, early leaf drop disease, and anthracnose. At the same time, the following measures should also be taken.

1. Artificial pollination. Within 24 hours after the pomegranate flowers first open, use the tip of a writing brush to dot pollen or dip pollen water and apply it to the stigma of the pistil, which generally can increase the fruit set rate by 17%-29%.

2. Foliar fertilizer spraying. According to the characteristics of the pomegranate fruit's demand for mineral nutrient elements during growth and development, spray the leaves once each at full bloom and during the young fruit swelling stage with 0.2% borax + 0.2% potassium dihydrogen phosphate + 0.4% urea, which can increase yield by 17%-37%, and can also increase the sugar content of the fruit and improve fruit quality.

3. Flower and fruit thinning. Purposefully thin out excess flower buds at an early stage, retaining only 1 central flower bud per inflorescence, and thin out excess small fruits and deformed fruits, which can save nutrients and increase the fruit set rate.

4. Fertilization to preserve fruit. During the young fruit stage, apply 1 kg each of phosphate fertilizer and potassium fertilizer per tree.