The trees are planted in suspended chutes inside greenhouses, with sand as a substrate. Cevad-estufa allows more than 300,000 yerba mate plants to be allocated in one hectare, while the traditional field production system places around 2,200 plants/ha. Studies show that its yield can reach 90 tons in a hectare within a yea. Research has investigated not only how to optimize production, but also at its impact on the chemical composition of yerba mate leaves. Embrapa is looking for partner farmers to validate the system, as well as industries interested in the development of differentiated products. A new yerba mate cultivation system developed by Embrapa Forestry allows up to 10 harvests in 18 months, that is, an extra nine harvests on top of the one traditionally obtained with the crop in the same period. Named Cevad-estufa, a version of the Cevad system for greenhouses, it also has the potential to develop new products, especially different types of maté teas made from young leaves, as plants are grown like small bushes in chutes inside greenhouses. The system still has to go through validation with farmers, but the results are promising and can contribute to raising yerba mate to a higher standard in the market for tea and other higher value-added products, in addition to expanding its trade in Brazil and worldwide. According to researcher Ivar Wendling, Cevad-estufa is aimed at harvesting young leaves and not mature ones, which are traditionally used to produce the tea-like beverage served in calabashes called chimarrão. Just as black tea, green tea and white tea are made of Camellia sinensis leaves, which requires different processes, it will be possible to similarly process the leaves of yerba mate (Ilex paraguariensis) and generate teas with distinct flavors and higher concentrations of caffeine and antioxidants. This can also be potentiated with the use of improved yerba mate cultivars, which are expected to be launched by Embrapa Forestry within the next three years. High productivity and production speed In Cevad-estufa, the trees are set in a greenhouse, arranged in rows, in suspended beds containing sand that is duly prepared for this purpose. The spacing between them is 15 cm x 15 cm, and the plants reach 15 cm to 30 cm in height. Every 30 to 90 days, new shoots grow and can be harvested to prepare teas or for the extraction of compounds like caffeine and antioxidants, for example, which are found in higher concentrations in young leaves. The new system allows more than 300,000 yerba mate plants to be allocated in one hectare, while the traditional field production system places around 2,200 plants per hectare. In addition, Cevad-estufa provides up to 10 harvests in the 18-month period starting soon after the trees are planted, while in the traditional field production system only one harvest is reaped in the same period. “Every 60 days, on average, it is possible to collect new shoots and leaves. Results showed that it is possible to produce up to 90 tons of biomass per hectare a year in the new system, while the average Brazilian yield of yerba mate is 7.5 tons a year, according to the Brazilian Institute of Geography and Statistics (IBGE)", the researcher states. “They are not types of plantation that compete with each other. Each has a goal and different types of management,” Wendling says Implantation costs The adoption of Cevad-estufa, which totally differs from field cultivation, will require higher costs for implementation, since it involves investments in greenhouse facilities, chutes, acquisition of a large quantity of seedlings, technical assistance and specialized labor for the management, as well as fertilizers for suitable nutrition. “Despite the initial cost, the system offers great potential not only for productivity but also for the generation of differentiated raw material. With such advantages, the investment of the implementation is expected to be paid over time and generate good economic returns,” the researcher says. “In addition, it has higher potential for automation,” he adds. Assessment of yield and chemical composition in the shade The research that supported the viability of Cevad-estufa cultivation included a master's dissertation by student Natália Aguiar and two doctoral theses by students Jéssica Tomasi and Leandro Marcolino Vieira, from the Federal University of Paraná (UFPR), all of which were carried out at Embrapa Forestry. According to Aguiar, the purpose of the study was to use this yerba mate biomass production system for industrial purposes and to assess the influence of shading and of the yerba mate clone not only on the production of mature and young leaves in successive harvests, but also on their chemical composition. “The results showed that the system is technically feasible for the cultivation of yerba mate, with high biomass yield when compared to traditional field cultivation systems, with emphasis on the large production of young leaves,” he adds The master's student evaluated two yerba mate genotypes (one high and one low in caffeine) that are being developed by Embrapa Forestry, under five different levels of shade (0% - no shade, 40%, 51%, 76% and 82%) in a greenhouse, over the course of a year. “This study with yerba mate clones clarified questions related to the effects of shading on the production of biomass and bioactive compounds. All levels of shade reduced yerba mate yield, and we do not recommend above 76% of shade in the cultivation of the species in this system, as it reduced biomass production by more than three times”, she reports. She adds that “shading also had an influence on the contents of the compounds analyzed, such as higher caffeine content under higher levels of shade. However, the low leaf yield under such conditions does not make up for the adoption of shading. The difference between clones could also be observed in leaf mass yield and in the bioactive compound contents, which indicates the importance of selecting genetic materials for each industrial purpose,” Aguiar says Production in the system and chemical characterization Jéssica Tomasi's doctoral studies evaluated biomass production over a year and the composition of bioactive compounds using different clones and nitrogen dosages in their nutrient solution. The productivity results showed little oscillation over six harvests in a year, confirming the system's potential in terms of continuous production and the variation across genotypes. Tomasi also concluded that there is an influence of seasonality on the content of bioactive compounds like caffeine and different types of antioxidants. Another study on Cevad-estufa, conducted by PhD student Leandro Vieira, analyzed aspects related to the rooting of mini-rootstocks and the production of yerba mate fresh matter. The chemical composition of 15 clones was also assessed on their contents of caffeine, theobromine, phenolic compounds, sugars and total proteins. It was found that, in general, yerba mate genotypes have specific traits regarding chemical composition, yield, propagation potential, need for the use of plant regulators, seasonality, interval between harvests, among other aspects, which demonstrates how the studied cultivars can viably meet niche markets for specific products. “Fresh matter production in the new system proved to be unique, and such unprecedented results may become a cultivation system aimed at the production of raw material for the yerba mate industry,” Vieira asserts. In addition, two genotypes stood out for their high contents of total phenolic compounds, proteins, caffeine and high antioxidant activity. Another genotype showed high fresh matter yield in Cevad-estufa cultivation, which allowed the annual yield of 96.16 tons per hectare, according to the study. “Highly productive genotypes with differentiated chemical characteristics can result in products that attract considerable interest in the yerba mate industry. Thus awareness of each genotype's traits regarding nutritional requirements, cultivation, pruning, propagation, among other factors, has the potential to increase efficiency in the multiplication and cultivation of yerba mate”, the former PhD candidate asserts. Advantages of young leaves Teas obtained from Camellia sinensis are widely consumed worldwide, an interest that is also driven by their antioxidant properties. Tea varieties (white, green, black, yellow and oolong tea) correspond to the processing of specific parts of the plant. For example, white tea is made of newly grown buds, while green tea is made from young leaves. Black tea undergoes an oxidation process before drying. Such teas are highly valued in the Brazilian market and the cheapest can cost end consumers about USD29 per kilo. Several brands already sell tea blends with yerba mate; however, they use mature leaves, which mostly originate from the traditional process of yerba mate production and processing. According to Wendling, given the high yield and the possibility of generating other products with the young leaves of yerba mate, there is an expectation that this raw material, especially the buds, also has more value when compared to traditional yerba mate. “Especially if we consider that younger leaves and shoots contain higher concentrations of caffeine and antioxidant compounds, which are beneficial to human health,” the researcher points out. Cevad-estufa can result in antioxidant capsules, a novelty in the market Studies have pointed to the existence of around 200 chemical compounds in yerba mate leaves, many of which are potentially bioactive. With this new production system, in addition to specialty teas, it is possible to extract compounds for the production of cosmetics, food supplements and pharmaceuticals for different purposes. One of the options is capsules or sachets with yerba mate extract powder, which offer a significant antioxidant effect. Another product line comprises stimulants, due to the high quality and caffeine concentration in the young yerba mate leaves of improved genetic materials. “As far as we know, differentiated capsules are neither available on the market yet nor are caffeine and antioxidants extracted from yerba mate on a commercial scale, which makes these studies very promising,” Wendling underscores. Search for partnerships The next step is to validate the system with farmers. In addition, the idea is to find industries that are interested in this type of raw material for product development, once yerba mate has a strong appeal as a natural and sustainable raw material. Farmers and industries with an interest in testing Cevad-estufa and developing products stemming from the new system can contact Embrapa Forestry by email: cnpf.spat@embrapa.br.