What is the truth about soilless cultivation? The latest revelation is here
In Europe, such as the Netherlands, Denmark and some other countries and regions, a considerable portion of greenhouse vegetables and flowers are produced using soilless cultivation, and in the Netherlands soil cultivation of vegetables has already been restricted, because the use of soil cultivation pollutes groundwater, thereby polluting the environment, while the soil in turn also pollutes the plants. Soilless cultivation, however, is a completely closed system with controllable risks that does not pollute the environment, and is therefore strongly advocated. So what exactly is soilless cultivation technology?
1. What is soilless cultivation
Soilless cultivation is also called nutrient cultivation or hydroponics. It is a special cultivation method in which, when growing crops, no soil is used and no manure is applied; generally only a nutrient solution made from chemical reagents is used to supply the nutrients the crops need. It is both a method of growing crops in the laboratory and a research tool for conducting crop culture experiments in the laboratory. It is generally carried out in a relatively closed indoor environment, so the chance of infection by pests and diseases is very small and pesticides are rarely applied, making it possible to grow pollution-free, hazard-free crops.
2. The advantages of soilless cultivation
Soilless cultivation has made outstanding contributions to the development of contemporary agriculture. The main reason is that, compared with traditional agriculture, soilless cultivation can genuinely break away from agriculture's dependence on soil, reducing labor intensity and thereby freeing up more labor. At the same time, soilless cultivation makes more sufficient use of water and fertilizer, reduces the impact of pests and diseases, and can also increase crop yields, advancing the development of mechanized agriculture. The specific advantages of soilless cultivation are as follows.
(1) The most prominent advantage of soilless cultivation is that it breaks free from the limitations of soil. Soilless cultivation has changed the traditional concept of relying on land for survival, that “all things grow from soil,” and the traditional method of soil farming; crops can be grown in places unsuitable for farming, such as sand and gravel, barren land, and even on spacecraft. On windowsills, balconies, corridors, roofs and other idle spaces in homes and offices, plants can be grown. Using soilless cultivation technology, high-yield, high-quality vegetables have already been successfully produced on abandoned sites of the Shengli Oilfield and on saline-alkali land in Shouguang City, Shandong.
(2) Soilless cultivation can significantly reduce labor intensity while expanding the efficiency of water and fertilizer use. Soilless cultivation does away with the cumbersome steps of traditional farming such as plowing, weeding, soil disinfection and topdressing, so the scale managed per unit of labor can be greatly increased and labor intensity noticeably reduced. The water and fertilizer supply in nutrient solution cultivation generally uses a micro-pipe irrigation system, which makes it easier to achieve fixed-point, localized application and can significantly reduce waste of water and fertilizer. Experiments have shown that, compared with soil cultivation, it can save 3 to 7 times as much water and increase fertilizer utilization rate by 20% to 30%.
(3) Soilless cultivation reduces the impact of pests and diseases on crops. Soilless cultivation can prevent the occurrence of many serious diseases spread by soil-borne pathogens, cutting off a relatively important channel for the spread of pests and diseases; in addition, because the rhizosphere microenvironment is artificially improved, plants are prompted to grow robustly and their own disease resistance is strengthened, avoiding the soil salinization and continuous-cropping yield decline caused by years of salt accumulation and continuous cropping in soil cultivation. At the same time, disinfection of the substrate is more economical and convenient than soil disinfection.
(4) Soilless cultivation greatly increases crop yields. In countries and regions where soilless cultivation technology is relatively mature, yield per unit area can be increased by 0.4 to 20 times compared with soil cultivation (varying by crop, generally between 2 and 4 times), and trial demonstration results in China are also mostly above 30%.
(5) Soilless cultivation helps raise the level of automation in agricultural production. Soilless cultivation fully demonstrates that agriculture can produce crops with mechanization and automation just like industrial production, with plant growth entirely controlled by humans. Today there are already fully automated soilless cultivation facilities and three-dimensional soilless cultivation factories in the world.
3. The disadvantages of soilless cultivation
Besides its advantages and potential, soilless cultivation also has some aspects that are unfavorable for large-scale application and promotion. For example, the one-time facility investment is relatively large; the properties of various substrates are not yet understood in detail; and nutrient solution management is highly technical and difficult.
4. The applications of soilless cultivation
The one-time investment and annual operating costs per 667 sq m of the organic ecological soilless cultivation system are shown in Table 1 (excluding the investment in building a greenhouse or plastic tunnel). From Table 1 it can be seen that the one-time investment in the organic ecological soilless cultivation system is about 300 yuan per 667 sq m, and the annual production cost (including labor) is about 4,300 yuan per 667 sq m.
Taking tomatoes as an example, the annual yield per 667 sq m is 15,000 kg. At a general average market unit price of 1.5 yuan/kg, the total income is: 1.5×1.5=22,500 yuan. After deducting the production cost of 4,300 yuan, the net income is about 18,200 yuan/year/667 sq m. If sold at premium vegetable prices to high-end restaurants, hotels or for export, the output value and profit should be even higher.
Summary: To some extent, soilless cultivation technology provides a new way of thinking about growing food, but given the current technology, it has not yet been promoted on a large scale. The reason is that its disadvantages are obvious, many detailed characteristics of soilless cultivation are not yet understood, and since its development time is shorter than that of traditional agriculture, various technologies are far from reaching the level of mass production. At the same time, the management of nutrient solution culture is highly technical and demanding, making it unsuitable for widespread promotion in rural areas, and it is still at the experimental stage. But it is certain that soilless cultivation technology will absolutely occupy a place in future agricultural output, and with an increasingly sound market system, it will eventually achieve certain economic benefits.