Inta Oberá, Misiones, implemented a greenhouse semi hydroponic culture system using pipes and bags filled with a substrate of carbonized rice husk that facilitates strawberry production on a commercial scale. By eliminating the soil, the crops use 70% less pesticides when compared to field crops and the plantation's performance increases by up to 30 percent.
"As there is a lower incidence of pests and diseases, pesticide application decreased by 70 percent and can be replaced by the use of biological control and tillage techniques that improve the quality of the fruits that reach the consumer without affecting the profitability of production, "said Sergio Feversani, a technician from Inta Oberá who was responsible for the test.
Some of the system's advantages are that it prevents diseases caused by soil fungi, producers no longer depend on surface conditions and rotation schemes. "The system also helps reduce labour and improves the quality of life, as workers can work standing up," said Feversani.
The use of the production area can also be optimized and the number of plants per square meter can be doubled or even tripled. "One can plant between 12 and 15 strawberry plants per square meter in this type of system while, in traditional crops, one can only have 5 or 8 plants per square meter," specified Feversani.
Feversani also highlighted the system's potential for small and medium conventional producers who must renew all their plants at the beginning of each annual cycle of production. "To repeat a crop, they only need to replace the damaged bags because the substrate can be reused for two years," he said.
Regarding the economic aspect of this system, the technician stated that the cost of starting a semi-hydroponic strawberry culture was very similar to that of a traditional one. However, he said, "the advantages in the medium-term make it a recommended option."
Results
The specialist said that producing within a greenhouse facilitated the control of the effects of temperature and humidity on the plants. He also said that producers could obtain fruit 45 to 50 days after transplantation if they also used drip irrigation and seedlings of certified origin. Thus, producers could consolidate an eight-month production cycle.
Feversani said that according to the initial assessments of this module, which has been in its experimentation phase for two years, the production yield could increase by up to 30% if the nutrients are applied efficiently at each stage of the crop.
"We obtained between 800 and 900 grams of fruit per plant, i.e. 1,800 kilos per cycle and between 105 and 150 kilos on average per week," explained Feversani. He also said that the production had been "highly accepted by the consumers due to its firm consistency, aroma and deep colour."
The experiment was performed with a 2,000 strawberry plant culture located in a 189 square meters greenhouse in Oberá.
A new system
Unlike hydroponics, which promotes the growing of cultures in a water solution, the strawberry seedlings in the semi-hydroponic system develop in an alternative substrate and receive the nutrients needed to grow via fertilization through irrigation.
"The substrate serves as a support for the plants and allows the retention of the liquid with the nutrients needed for growth," said Feversani. He also said that, in addition to rice husks, producers could use some peat and mineral derivatives as perlite and vermiculite as the substrate. Given the shallowness of the strawberry seedlings' roots, they can be planted in PVC pipes or small bags. In this line, Feversani said: "The lack of contact with the soil reduces the attack of diseases and, if they arise, producers only have to get rid of the infected pouch and not all the production area."
"After the plants are transplanted, they need to be fertilized via irrigation to supply them with the nutrients they need to grow, have a good quality and crop health," he stated. He also said it was possible to adapt this system for the production of lettuce, spinach, cucumber and tomato.
"While this system requires technical monitoring, this alternative allows producers to obtain a product that meets the requirements of an increasingly demanding market and reach the unmet local productive demand," concluded Feversani.
Source: Inta