Floating cultivation (DFT = Deep Flow Technique) is a serious option for emission-free cultivation. In this cultivation technique the plants hang in floating panels, that are floating on a few decimeters deep nutrient solution. Almost the entire root development takes place in the nutrient solution.
More productive systems
New, more productive systems are required because the growing world population increases the need for food. In addition, the quality of the soil is decreasing worldwide because of, for example, one-sided fertilization, which is why better cultivation systems must be conceived. "We also need to use fertilizers more efficiently, because the phosphate fertilizers that are still widely used, are becoming scarce. And you will lose fertilizer when you are rinsing out", says Matthijs Blind, researcher at Proeftuin Zwaagdijk. "Additionally, attention must also be paid to the living environment, nature and the environment. Scarcity of good water, climate change and the circular economy also play a role."
Basic systems
There are two basic systems for a floating cultivation. With one system there is direct contact between the plant plug in the floating panel and the water; with another system there is no direct contact between the plant plug and the water. The plug and water are separated from each other by a layer of air and the plugs must be moistened until the roots have grown to the nutrient solution. For example, by temporarily loading the floating panel in the starting phase, a mixed form is created.
Suitable crops
Various fruit vegetables and herbs can be grown well on a floating system, but the system also seems to offer perspective for cut flowers and perennials. Blind: "The floating cultivation of chrysanthemums has also been studied in recent years. The cultivation on water is going well, but the production is still too variable." In addition, there are also crops with (temporarily) poor or difficult development or still too risky for floating cultivation. Examples include cauliflower (quality decreases), parsley (crop recovers too slowly after a harvest), spinach, phlox, aconitum, callistephus and delphinium. According to the researcher, if breeders also would focus on floating cultivation while selecting and breeding, it would strongly stimulate the development of the new cultivation technique.
Advantages
The most important advantages of a floating cultivation are: better control, cleaner product, fewer soil-related disease and pest problems, such as weeds, snails and thrips. "In twelve years' time, we have had no problems with water-related diseases, even without disinfection," according to the researcher.
An advantage is that with a floating cultivation the emission requirements in (future) legislation, such as the Water Framework Directive, can be complied with. Moreover, the plants are mobile, so that with automation and mechanization the labor productivity can be increased and working conditions can be improved.
Challenges
A floating cultivation is relatively new. It entails all kinds of challenges that require attention, in order to come to clarity and solutions. For example for the cultivation-technical issues, reliability and risks, investments and depreciation costs, fast depreciation of floating panels (because of technical developments), the biotope in the water and footprints of energy and materials.
Suppliers
There are several suppliers who each supply their own floating cultivation system: Dry Hydroponics, Botman Hydroponics, Industrial product Solutions, Viscon Hydroponics and Meteor Systems.