What are the key technical points of planting and management of plastic film onion?

The planting period of onion can be divided into autumn planting and spring planting according to different cultivation areas. there are many rows of autumn planting in the south of Beijing and spring planting in the north of Beijing. At present, plastic film technology is often used in onion planting, so what are the key points of planting management of plastic film onion?

1. Planting time of plastic film onion

Autumn planting is mostly adopted in the south of the Great Wall, which is planted about 40 days before the severe cold, so that the onion root system resumes growth before overwintering, the leaf grows rapidly after turning green, and the seedling growth period is long, so it is more high-yielding than spring planting.

Autumn planting should be timely, early, too large seedling growth before winter, will cause early bolting in spring; too late, short growth period before winter, root system can not be fully developed, cold tolerance is reduced, easy to cause overwintering dead seedlings.

To the north of the Great Wall, the winter is so cold that it is difficult for onions to survive the winter in the open field, mainly planted in spring. The leaf growth period of spring planting is short and the yield is on the low side, so the planting in spring should be carried out as early as possible after soil thawing, so as to strive for a longer growth period, grow more functional leaves before bulb expansion and increase yield.

2. Key points of planting techniques of plastic film onion

1. Fertilizing to make beds

Onion is a fertilizer-loving vegetable crop, and the lack of any element in nitrogen, phosphorus and potassium fertilizer will lead to a reduction in yield. In order to achieve high quality and high yield, sufficient base fertilizer must be applied. Generally, 50 kg of sulfur-based compound fertilizer with low nitrogen, high phosphorus and high potassium and 5000 kg of mature farm manure are applied per mu. Spread the fertilizer evenly and plough the soil, loosen and rake the soil and make it into a bed 100 to 120 centimeters wide.

2. Choose strong seedlings

Before transplanting, onion seedlings are required to be 50-55 days old, when the seedlings are easy to root and recover quickly after transplanting. The diameter of the seedlings is 5-6 mm and the seedling height is about 25 cm. 10-15 days before transplanting, the seedlings were sprayed with potassium dihydrogen phosphate foliar fertilizer, which could promote the seedlings to take root early after planting.

3. Covering plastic film

Plastic film cultivation can enhance the cold resistance of onion in winter, improve the ability of soil water and fertilizer conservation, and greatly increase the yield of onion. Before mulching, enough water should be irrigated to make moisture. After all the water in the border has seeped, 33% herbicide 100 ml per mu is sprayed when the soil is wet, evenly sprayed on the border surface, and then covered with film. When covering the film, you should choose windless weather and firmly press the soil on both sides of the film, otherwise the film will be damaged by the wind, and it is not convenient for field operation.

Warm reminder: when planting, it is necessary to cover the plastic film 5 days before transplanting to increase the ground temperature. Punch holes in the plastic film before transplanting, the row spacing is 18 cm, the plant spacing is 15 cm. Immediately after transplanting, the root should not be exposed on the surface, but it should not be too deep, and the planting depth should be controlled at 2 cm to 3 cm.