Its main revenue is dependent on either tourism or on the production of fruits and flowers. Dalat city has limited revenue sources and no natural resources, so it cannot develop any industry.
Because of this Dalat is currently facing a very difficult situation as to whether it should continue to develop its greenhouses or not, as now they have become a source of warming of temperatures.
About ten years ago, farmers in Dalat and people who had leased cultivable land were excited about making a particular type of greenhouse. This is a greenhouse design that is made of pre-engineered steel framework, with a thick white nylon roof or clear plastic roof sheeting. This type of greenhouse always kept the internal temperature of the soil warm and moist, prevented water from evaporating, and also prevented damage to plants from severe frost and insects.
For these reasons, greenhouse farming was seen as superior in productivity and efficiency compared to traditional farming. One hectare of greenhouse covered land area could yield nearly VND 350 mln to VND 1 bln, depending on crop.
Currently, 100% of flowers exported from Dalat in particular and Lam Dong province in general, are to the tune of about 300 million branches per year, all grown in greenhouses. Most of the vegetables for export, and vegetables supplied to 4-star and 5-star hotels in the Ho Chi Minh City area are grown in greenhouses for high quality yield. Now, unfortunately, the uncontrolled growth investment in greenhouse development has led to serious and harmful consequences.
There are hundreds of thousands of farms and greenhouses in the outskirts of Dalat, running along both sides of the Cam Ly stream. From downstream to upstream, thousands of hectares of land are covered with tarpaulins for agricultural production. At the end of the 1990s, Dalat had only a few greenhouses, but now the area of greenhouses has increased to about 15,000 ha out of a total of 18,000 ha for vegetables and fruits.
Greenhouses are concentrated in all wards and communes, even in some places in the inner city which have greenhouse density in wards 5, 7, 8, 9, 11, and 12. Seen from above, Dalat seems overwhelmed by greenhouses, and the green belt surrounding the city has disappeared. Instead, it has been replaced by thousands of greenhouses, with the majestic pine forests scattered in few clusters in the suburban areas of the city.
Greenhouses have made the general temperature of the Dalat area rise and increase by 1 degree to 1.5 degree Celsius, because the surface of the synthetic roofs does not absorb heat but bounces it back into the atmosphere. This has caused hotter temperatures in the area, even more than from an entire house made of concrete. Summertime in Dalat has now become even more hotter, while the cold season is too short.
Land areas covered with greenhouses have a zero permeation coefficient, which means that rain falls on plastic sheets that does not penetrate into the soil. Hence, despite heavy rainfalls, the inside of a greenhouse remains absolutely dry, which means that the water does not seep into the ground. The city uses mud bags and water storage bags to replenish ground moisture. The loss of natural water storage has caused some places in the central area such as Phan Dinh Phung, Nguyen Cong Tru, Ngo Van So, To Ngoc Van, Mac Dinh Chi, and Truong Van Hoan to flood after heavy rains that may last for a few days, with no drainage flow for the water to go out of the area.
In order to tackle this situation, the People’s Committee of Lam Dong Province has planned that after 2030, several of these wards in Dalat City will do away with greenhouses. This policy decision has now become a seriously debated hot topic in scientific forums, seminars, and among the public. Both removal or maintenance of greenhouses is proving to be a growing and difficult problem that needs to be studied very carefully to find a reasonable and rational solution.
There are many opinions that say that greenhouses must be removed as quickly as possible and the green space be restored for Dalat. However, the situation is far more complex and difficult to tackle in a simple way. Up to now, Dalat has only dismantled about 71.6 hectares of construction sites, greenhouses, and other housing structures because they were built on land planned for forestry. Because this is not agricultural land it cannot be evicted forcibly. On this land, agricultural planning is not possible because people are legally cultivating their own land, hence they are not violating rules of public land and greenhouses are mostly on private property.
Moreover, agriculture and tourism are two main strengths of Dalat that have been encouraged to develop over the years. If the greenhouse system is demolished, then agriculture that produces vegetables, fruits, and flowers will suffer immediately. It will have an effect on the people's income, the source of vegetables, fruits, and flowers for export, and there will also not be enough vegetables and fruits to supply to the provinces, especially Ho Chi Minh City.
The agricultural products themselves serving millions of tourists who come to Dalat every year, and this may also reduce the number of tourists visiting this region. Another problem that is arising is that it will be difficult for farmers to return to growing fruits and flowers in the traditional way, for reasons of low productivity and also lack of knowledge of traditional techniques.
Serious questions are now arising as to how farmers in Dalat can still produce fresh fruits and vegetables with high yields and good quality, and if Dalat can once again regain its green space, natural landscape, and cool climate. Currently there are ongoing consultations with Japanese experts, and persons of skills working in Dalat. According to them, there are two options or solutions.
The first solution is for replanning all the greenhouse areas on a large scale in a methodical way in districts far from Dalat city, approximately 20 to 30 kilometers away such as in Lac Duong, Dran, and Nam Ban. These places will form modern ecological agricultural cities, with the main function of producing fresh vegetables, fruits, and flowers grown under the latest technology, automation, and industrialization processes in all stages from tillage to harvesting. This model has already been applied in the UAE countries and several cities in China, South Korea, and Japan.
The second solution is to make vertical greenhouses that are multi-storey with about ten to fifteen floors in the periphery of Dalat city, instead of ground level greenhouses spread over large areas of land within the city. This solution offers saving of space, does not affect the landscape, and can be used as an attractive tourist destination where visitors can go on agricultural tours. These solutions seem more harmonious, and economically and environmentally much more beneficial for farmers as well as the people of Dalat.