What types of greenhouses are there in foreign countries? What are the lessons for domestic greenhouse construction?

Modern greenhouses (especially developed countries) are dominated by large multi-span greenhouses, of which plastic film greenhouses are about 600,000 square kilometers (including Chinese solar greenhouses and plastic greenhouses), mainly distributed in Asia; glass greenhouses are about 40,000 square kilometers kilometer, mainly distributed in Europe and the United States; the new covering material polycarbonate board (PC board) greenhouse has developed rapidly in recent years, currently there are more than 10,000 hectares, scattered in countries around the world.

The Netherlands, the United States, Israel and other countries have vigorously developed the intensive greenhouse industry. The temperature, light, water, gas and fertilizer in the greenhouse have been controlled by computer, and a complete set of standardized technical systems have been formed from variety selection, cultivation management to harvesting and packaging. .

U.S.

The first recorded greenhouse in the United States was built in 1737 by the wealthy Boston businessman Faneuil to grow fruit. By 1825, American greenhouses were common, and many were heated with gas heated by coal stoves. Some greenhouses were built underground and relied on south-facing windows for heating, which can still be seen today. In the late 19th century, with the rise of heavy industry in the northeastern United States, the greenhouse industry also developed rapidly in the United States. The concept of greenhouses has become more popular and practical. It is no longer just for the rich or owned by the rich. Anyone who is interested can have a greenhouse that they can afford.

The greenhouse area in the United States is about 19,000 square kilometers, most of which are glass greenhouses, and a few are double-layer inflatable plastic film greenhouses. In recent years, a small number of polycarbonate panel (PC) greenhouses have also been built. Most of the plastic greenhouses in the United States adopt a hemispherical structure, the skeleton is made of special-shaped steel, and the covering materials are mainly polyethylene, polyvinyl chloride, vinyl acetate film, and some greenhouses use glass fiber resin panels. In the United States, greenhouses are mainly used for growing flowers, accounting for about 2/3 of the total greenhouse area.

The United States is the first country to invent computers, and it is also one of the earliest and largest countries to apply computers to greenhouse control and management. The United States has developed facility cultivation technology, and the level of comprehensive environmental control technology is very high. The environmental control computer is mainly used to monitor and control the greenhouse environment (meteorological environment and cultivation environment). Taking the flower greenhouse as an example, the monitoring items in the greenhouse include indoor temperature, water temperature, soil temperature, boiler temperature, pipe temperature, relative air humidity, etc.; outdoor monitoring items include atmospheric temperature, solar radiation intensity, wind direction and speed, relative humidity, etc. The application of the greenhouse expert system brings certain economic benefits to the growers, improves the decision-making level, reduces the workload of technical management, and also brings great convenience to planting.

In recent years, as people pay more and more attention to food safety and health, in order to avoid the harm of food contamination to health, many families in the United States have introduced gardening techniques and added some new ideas on the basis of traditional gardening, turning their backyards into practical plantations. . In order to produce food in the courtyard in various climates throughout the year, courtyard greenhouses came into being. In the past 10 years, various greenhouses have appeared in the back gardens of American residents, such as greenhouses attached to the side walls of houses, free-standing glass greenhouses, free-standing plastic film greenhouses, network hemispheric greenhouses, etc. Some courtyard greenhouses are built on the roof or balcony or installed on the deck of the ship.

Netherlands

The Netherlands is a country with very limited land resources. It has expanded its arable land by means of reclaiming the sea and reclaiming lakes. The per capita arable land is only 0.2 hectares. However, it can mainly rely on modern facilities for horticulture and aquaculture, and has become an agricultural exporter after the United States and France. .

The Netherlands is a country with very developed facility horticulture. At present, there are 17,000 hectares of smart greenhouses, all of which are glass greenhouses, accounting for 1/4 of the world's glass greenhouses, mainly used for growing flowers and vegetables. Vegetables produced in Dutch greenhouses account for 3/4 of the country's total vegetable output value, and most of them are sold all over the world. The flower industry in the Netherlands is very developed, mainly relying on greenhouse cultivation. It is the world's largest flower exporter and the world's flower trade center.

The smart greenhouses in the Netherlands are in the forefront of the world in terms of area, scale and level, but there are no enterprises specializing in the production of greenhouses. Although there are some professional manufacturers of accessories, the production of greenhouses and supporting facilities is completely dependent on a highly socialized, international market system.

The covering and insulation materials of the Dutch greenhouse are imported from Belgium, Sweden and other countries. The operation of greenhouse construction mainly depends on greenhouse engineering companies. There are 7 to 8 greenhouse engineering companies with international export capabilities. Design, project budget, material purchase, project outsourcing, etc., fully reflect the characteristics of intelligent greenhouse project construction. Holland's greenhouse engineering companies have provided engineering services for the Netherlands and Europe, and expanded cooperative business to countries all over the world, especially developing countries.

Japan

The first greenhouse in Japan was built by British businessman Samuel Cocking in 1880 for the export of medicinal materials. Since the 1960s, the modern facility horticulture industry has developed rapidly, and greenhouses have developed from single buildings to multi-building large-scale and metallized structures. In the period of rapid development in the 1970s, the government provided farmers with subsidies for large-scale modern intelligent greenhouses, of which 50% was subsidized by the state, 30% to 40% of other subsidies, and only 10% to 20% of the funds paid by farmers themselves. Promote the development of the facility horticulture industry. In 2011, Japan had 51,200 hectares of modern smart greenhouses, mainly plastic film greenhouses; while glass greenhouses in Japan were mostly multi-span greenhouses with double-roof and double-roof.

other areas

In the Mediterranean coast, due to better climate conditions, in 2011, Italy had 72,800 hectares of smart greenhouses, France 26,500 hectares, Spain 71,700 hectares, and Portugal 2,000 hectares, mainly large multi-span plastic film greenhouses; some Eastern European countries, such as Hungary There are 2,300 hectares of intelligent greenhouses, 3,600 hectares in the Czech Republic, and 1,200 hectares in Romania, mainly glass greenhouses. The overall level of the main frame, supporting equipment, and control technology is lower than that of the Netherlands; there are 16,700 hectares of intelligent greenhouses in northern Europe, mainly glass greenhouses. . The Americas have 15,600 hectares of smart greenhouses.