Author: Cao Yongchun
Tunisian soft seed pomegranate, like temperature, drought tolerance, fear of frost and waterlogging, suitable for sandy loam cultivation. The tree posture is moderate, the branches are dense, the branching rate is strong, the young branches are red, the old branches are brown, and the side branches are mostly curly; the young leaves are purple-red, the leaves are narrow and long, the oval type, the thick green, the thorny branches are few; the petals are red, the total flower volume is large, the complete flower rate is about 34%, the flowers are gourd-shaped, tubular and bell-shaped; the fruit setting rate is more than 70%, the fruit is round, the peel is close to maturity from yellow to red, and the fruit is fully red at the outer periphery after maturity, and the peel is smooth and bright; the seed is purple-red, the seed is soft, and the seed yield is 61.9%.
The absorption of potassium by plants also depends on the plant species, and the order of potassium demand is: sugarcane ~ watermelon ~ banana ~ pomegranate ~ sugar beet ~ tobacco ~ potato.
Tunisian soft-seeded pomegranates have the greatest demand for potassium and calcium, followed by nitrogen and finally phosphorus. Tunisian soft-seeded pomegranate needs to meet potassium supplementation before the two expansions of the fruit. Potassium nitrate supplementation is provided in combination with amino acids before flowering (3 under 4 upper), if potassium fertilizer is not supplemented before flowering, potassium nitrate must be supplemented in the early fruit expansion stage (5 under 6 upper) of the fruit tree. The fruit should be supplemented with potassium sulfate before the secondary expansion stage (7 under 8).
Potassium is a necessary component for plant growth, potassium is more concentrated in the most metabolically active organs and tissues of plants, such as growth points, buds, young leaves and other parts, plants selectively absorb water-soluble potassium ions in the soil from the soil through the root system.
Potassium's nutritional functions on plants include: promoting the activation of enzymes in plants, enhancing photosynthesis, promoting sugar metabolism, promoting protein synthesis, enhancing plant drought resistance, cold resistance, salinity resistance, disease and pest resistance, etc. At the same time, potassium fertilizer also plays an important role in improving the quality of plant products, so potassium is called "quality element".
The main characteristics of potassium deficiency in plants: old leaves and leaf margins first yellow, and then brown, scorched like burning, brown spots or plaques appear on the leaves, but the middle of the leaves, leaf veins still remain green, with the intensification of potassium deficiency, the entire leaf becomes reddish brown or dry, necrotic and fall off. Potassium deficiency in Tunisian soft-seeded pomegranate: the old leaf margins of the lower and basal parts turn yellow, necrotic tissue gradually appears, and the fruit is not sweet enough.
Potassium deficiency and magnesium deficiency are more similar, will cause the lower leaves of the fruit tree to yellow, but the difference is: after potassium deficiency, the leaf margins of the old leaves first turn yellow, and then brown, scorched like burning, brown spots or plaques appear on the leaves, with the intensification of potassium deficiency, the entire leaf becomes reddish brown or dry, necrotic off; magnesium deficiency is that the leaf veins of the lower leaves of the fruit tree are green, and the middle of the leaf veins is yellow, severe magnesium deficiency, the entire leaf from yellow to white, and finally fall off.
Potassium has a great effect on plants, known as one of the three elements of fertilizer, because potassium has a significant impact on the growth and development of plants and the entire metabolic process.
1. Promote the activation of enzymes. Enzymes are catalysts in plants, and activated enzymes participate in biochemical processes such as sugar, protein and nucleic acid metabolism in plants, which have unique physiological effects on plant growth and development. In other words, once the enzyme is deficient in the fruit tree, all the nutrients absorbed by the roots and leaves have zero effect.
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2. Solidify and promote the utilization of light energy. Potassium enhances photosynthesis, especially in conditions of insufficient light, and works better. Tunisian soft-seeded pomegranate prefers light and temperature, and in the area north of the Yellow River, due to the large oblique angle of light and insufficient accumulated temperature, the demand for potassium fertilizer is greater.
3. It is conducive to the normal respiration of plants. High or low temperatures are not conducive to the leaves of fruit trees absorbing carbon dioxide in the air and using photosynthesis to create nutrients, while potassium can improve energy metabolism, regulate leaf stomata closure, reduce respiratory consumption, and thus increase yield.
4. Enhance the synthesis and operation of carbohydrates, proteins, nucleic acids and fats and other nutrients in plants. Although carbon, hydrogen, oxygen, and nitrogen are all important, without the action of potassium, the fruit is difficult to expand, sugar and color.
5. It can enhance the anti-freezing, drought-resistant, flood-resistant, salt-resistant and disease-resistant ability of plants, and can also improve the metabolism of fruit tree root systems and reduce the harm of reducing substances under flooded conditions. The reason why tunisian soft-seeded pomegranate is difficult to sustain in the northern region is not due to climate and soil, but to the lack of underground management and nutrient supplementation.
Tunisian soft-seeded pomegranates can actually be grown in the south except for the cold-weather northeast and the windy and sandy inner Mongolia. However, in the north of the Yellow River, due to the severe cold in winter and the cold in spring, the phenomenon of freezing to death often occurs. The eugenic area of Tunisian soft-seed pomegranate is mainly a temperate region south of the Yellow River, which is famous for its thin skin, sweet seeds, shelf life and rich nutritional value, but due to poor management, the cultivation of Tunisian soft-seed pomegranate is gradually moving south and westward.