What is the truth about soilless growing? This article reveals it for you
In Europe, such as in 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 using soil cultivation pollutes groundwater and thereby pollutes the environment, while the soil in turn pollutes the plants. Soilless cultivation, however, is a completely closed system with controllable risks that does not pollute the environment, so it is strongly advocated. So what exactly is soilless cultivation technology?
I. 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 crop cultivation experiments in the laboratory. It is generally carried out in a relatively enclosed indoor environment, so the chance of infection by pests and diseases is very small and pesticides are rarely applied, which means it can produce pollution-free, hazard-free crops.
II. 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, reduce labor intensity and thus free up more labor. At the same time, soilless cultivation makes more complete 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 following are the specific advantages of soilless cultivation.
(1) The most prominent advantage of soilless cultivation is that it breaks free from the limitation of soil. Soilless cultivation has changed the traditional concept of relying on land for survival, that “all things grow from soil,” and the traditional way of cultivating soil. In places unsuitable for cultivation, such as sand and gravel, barren land, and even on spacecraft, crops can be grown. In homes and offices, plants can be grown on windowsills, balconies, corridors, roofs and other idle spaces. 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 also expanding the use efficiency of water and fertilizer. Soilless cultivation does not require the cumbersome steps of traditional farming such as plowing, weeding, soil disinfection and topdressing, so the scale that a unit of labor can manage can be greatly increased and labor intensity clearly declines. 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 water by 3 to 7 times and increase fertilizer use efficiency 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 and cuts off a relatively important channel for the spread of pests and diseases; in addition, because the rhizosphere microenvironment is artificially improved, plants are promoted to grow robustly and their own disease resistance is enhanced, 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 0.4 to 20 times higher than soil cultivation (varying by crop, generally between 2 and 4 times), and trial demonstration results in our country 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 completely controlled by humans. Today there are already fully automated soilless cultivation facilities and three-dimensional soilless cultivation factories in the world.
III. Disadvantages of soilless cultivation
Besides the advantages and potential that soilless cultivation has, it also has some aspects that are unfavorable to 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.
IV. Applications of soilless cultivation
For the organic ecological soilless cultivation system, the one-time investment per 667 sq m and the annual operating cost 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 for the organic ecological soilless cultivation system is about 300 yuan/667 sq m, and the annual production cost (including labor) is about 4,300 yuan/667 sq m.
Taking tomato as an example, the annual yield per 667 sq m is 15,000 kg. At an average market 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, then the output value and profit should be even higher.
Summary: To some extent, soilless cultivation technology provides a new approach for growing food, but with 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 its development time is not as long as that of traditional agriculture, so various technologies are far from reaching the level of mass production. At the same time, the management technology for cultivating nutrient solutions is demanding, so it is not suitable for large-scale promotion in rural areas and is still at the experimental stage. But it is certain that soilless cultivation technology will absolutely hold a place in future agricultural output, and together with an increasingly sound market system, it will ultimately achieve certain economic benefits.