Prevention of fruit cracking in planting pomegranate

Fruit cracking is a common problem in pomegranate production, which can occur from young fruit stage to mature stage, especially in the 15 days before fruit harvest. The cracking rate is generally 9% in light years and up to 30% in heavy years; fruits are perishable after cracking, cannot be kept fresh or stored, and commodity and edible value are reduced or lost, resulting in significant economic losses. The preventive measures are:

The main results are as follows: 1. The selection of pomegranate fruit cracking resistance is related to the characteristics of the variety. In general, varieties with early maturity, flat and round fruit shape, thin pericarp and easy aging are easy to crack fruit; late maturity, green skin, copper shell, thick and rough pericarp, rust-colored varieties are not easy to crack fruit. Linxuan 8, Linxuan 14, Taishanhong, Yu pomegranate 1, Yu pomegranate 2, Yu pomegranate 3 and so on are all excellent varieties with strong resistance to cracking.

2. The reasonable selection of pomegranate cracking fruit at the garden site is related to the site conditions. In general, in the soil with shallow tillage layer and thin active soil layer, the pomegranate tree has poor growth, low yield, heavy fruit cracking and deep ploughing layer, the pomegranate tree has good growth, high yield and light fruit cracking, light fruit cracking in irrigated land and heavy fruit cracking in dry slope. In addition, the soil with heavy clay has poor air permeability and heavy fruit cracking. Therefore, for planting pomegranate trees, it is appropriate to choose plots with deep soil layer and watering conditions; if a garden is built on dry sloping land, soil improvement should be carried out and soil and water conservation should be done well to prevent soil erosion.

3. The purpose of reasonable pruning is to improve the ventilation and light transmission conditions in the garden, promote coloring and prevent fruit cracking. In winter pruning, thinning or retraction of some large crossed branches and overlapping branches, adjusting the subordinate relationship of backbone branches at all levels, thinning and retraction of peripheral dense fruiting branches and weak drooping branches, and summer pruning, mainly wiping buds, coring and pruning, etc. The useless and dense branches should be erased as soon as possible, and the useless branches should be removed in time. The branches with space can be transformed into fruiting branches by coring and twisting.

4. In the early stage of fruit growth, the orchard is covered with plastic film or crop straw, which is beneficial to maintain soil moisture, prevent the setting of the garden and reduce the cracking of pomegranate fruit. In addition, planting green manure, legumes or other dwarf cash crops in pomegranate orchards has the same effect.

5. Rational fertilization and pomegranate irrigation should be based on the principles of small amount, balance, multiple times and proper control. In production, generally, during the period of rapid growth or expansion of young fruit, water is irrigated every 10 days; before the rainy season, the times of irrigation are gradually increased, and water is sprayed on the crown every 10 days, so as to increase the air humidity in the garden, moisten the peel, enhance the adaptability of the peel to continuous rain and high temperature, and prevent fruit cracking; stop watering before the fruit is about to mature.

6. rational fertilization of pomegranate trees should be based on organic fertilizer, with sufficient phosphorus and potassium fertilizer and less nitrogen fertilizer as far as possible. During the fruit expansion period, foliar spraying with 0.3% potassium dihydrogen phosphate or 0.5% calcium chloride solution is helpful to enhance the pericarp toughness and prevent fruit cracking.

7. Rational control in the middle and later stage of pomegranate fruit development, spraying fruit surface with 25 mg / L gibberellin solution can reduce fruit cracking by 30%. In addition, at the calyx depression of pomegranate fruit, a strip of rubber cloth soaked in 10 Mel 30 mg / L gibberellin solution, or 0.3% paclobutrazol solution and 20 Mel 25 mg / kg ethephon solution was also applied to reduce or prevent fruit cracking.

8. Fruit bagging is generally carried out in the young fruit stage, which has the functions of disease prevention, insect prevention and fruit cracking prevention. Bagging has a certain cushioning effect on the drastic changes of temperature and humidity, which can protect the pericarp, reduce the burn of the pericarp caused by sunlight during the dry period and the damage of persistent high humidity to the fruit toughness, so as to prevent fruit cracking.

In addition, it is necessary to control fruit pests in time.