High-yielding cultivation of pomelo with south fruit moving from south to north

The main results are as follows: 1. the cultivation technique of planting and establishing garden pomelo south fruit moving northward is carried out by the combination of open air and plastic film in greenhouse, and the whole growth period is divided into open-air cultivation management and protected field cultivation management, that is, from the beginning of October to the beginning of May of the second year, the local conventional winter warm greenhouse cultivation management is adopted, which belongs to protected field cultivation management; at other times, it can grow in the open air after film removal, which belongs to open-air cultivation management. The planting time is from February to March of each year. When planting, the row spacing was 3 × 2 meters, 111plants were planted per mu, ditching or digging planting holes were adopted, and the depth was 60cm, followed by the application of high quality soil fertilizer or circle fertilizer, generally 5000 kg per mu and 100kg mixed compound fertilizer. Should be fully irrigated and covered with plastic film after planting.

Second, the comprehensive management of soil, fertilizer and water in the greenhouse should be strengthened in the year of fertilizer and water management. Pomelo can be topdressing 1 month after planting, and then topdressing every 1.5 kg of urea or compound fertilizer every 2 months. Adult pomelo should be fertilized 3 times per year for 5 times, that is, one basal fertilizer and multiple topdressing. Base fertilizer is generally applied after fruit harvest, each plant can apply high-quality organic fertilizer 30ml 50kg, plus calcium magnesium phosphorus 0.5kg 1kg. This application should account for 60% of the total amount of fertilizer applied in the whole year. Fruit protection fertilizer is applied from June to July, accounting for 10% of the whole year, and the amount of phosphorus and potassium fertilizer is increased. Flower-promoting fertilizer was applied from September to October, accounting for 20% of the whole year, with the combination of nitrogen, phosphorus and potassium. Strong fruit fertilizer is applied from December to January of the following year, accounting for 10% of the whole year, mainly potash fertilizer. In addition to the normal soil fertilization, the application method should also pay attention to the application of extra-root topdressing for many times. Special attention should be paid to spraying 400 times borax solution during flowering to promote pollination and fertilization and improve fruit setting rate. Spraying 0.3% urea and 0.2% potassium dihydrogen phosphate in the young fruit stage can reduce fruit drop and promote fruit expansion. Spraying 0.2% potassium dihydrogen phosphate solution during flower bud differentiation can promote nutritional transformation and make flower buds full. Watering should be carried out at the same time as fertilization. Grapefruit likes a humid environment, so the relative water content of the soil should be kept at 60% 80%, and a small amount of water should be mastered for many times when irrigating.

Third, shaping and pruning mainly adopts natural happy shape or "v" shape pruning, the height of the fixed stem is about 50 cm, the number of main branches is 2mur3, and the lateral branches are misplaced on both sides of the main branches, and show horizontal or curved shape. In pruning, different pruning methods are mainly adopted, such as truncation, slow release, thinning, retraction and so on, so that the new branches can achieve the purpose of results. In addition, the fruit branches should be renewed after fruit harvest. This can promote the early flowering of the plant and lay the foundation for the next year's high yield.

Fourth, the control of temperature and humidity from the beginning of October to the beginning of May of the following year is the growth period under artificially controlled greenhouse conditions, and can grow completely in the open air at other times. Therefore, it is very important whether the regulation of temperature and humidity under protected cultivation is reasonable and proper. The temperature and humidity regulation of pomelo south fruit northward cultivation is as follows: the temperature during the fruit expansion period is 28 ℃ 32 ℃, 10 ℃ at night, and the relative humidity is 60% 80%; during the near-ripening period, the relative humidity is 26 ℃ during the day and 8 ℃ at night, and the relative humidity is 60% 80%; during the young shoot growth period, the relative humidity is 1722 ℃ during the day, > 5 ℃ at night, and the relative humidity < 80%; the flowering period (April) is 2225 ℃ during the day and 12 ℃ at night, and the relative humidity is about 60%.

5. pest control should adhere to the principle of "prevention first and comprehensive control". On the basis of strengthening comprehensive management and improving the disease resistance of trees, biological agents and pesticides with high efficiency and low residue should be sprayed reasonably. In the cultivation observation, one of the main diseases and insect pests of pomelo is powdery mildew and the other is leaf moth. For powdery mildew, spray 5 Baomedo stone sulfur mixture before germination; use 3000 times of 20% triflon EC or 2000 times of 30% Teflon during the growing season. For leaf miner, 1.8% avermectin EC 3000 times can be sprayed during the occurrence period.

Sixth, picking and harvesting grapefruit have been on the market from late December to February of the following year, the picking period is as long as 2 months, and its main maturity period is controlled around the Spring Festival. Due to picking by stages and going on the market while picking, the high yield of 1000 kg per mu per year, 2200 kg per mu in two years and 4100 kg per mu in three years can be achieved.