Citrus growers gain organic Tahiti lime production system

Specialists from Embrapa and partners have developed yet another organic fruit production system, that of the Tahiti acid lime, popularly known as Tahiti lemon. The organic system for the production of this fruit, one of the main exported by Brazil, was developed based on experiments carried out in the area of ​​the company Bioenergia Orgânicos, in Lençóis, in Chapada Diamantina (BA), being recommended for this region, but the proposal is that serves as a model and can be adjusted for other production centers in the country, as it encompasses the basic principles of organic production.

The experiments recorded productivity of 30 tons per hectare (t/ha), in the sixth year, a value higher than the national average records in conventional mode, around 26 t/ha. The number is well above the average productivity of the state of Bahia, which in 2021 was close to 12 t/ha (IBGE), which can also be explained by the use of irrigation in the work carried out in Lençóis.

Although the yield is similar to the Brazilian average, this result was celebrated by the research team, as it represents yet another incentive for organic cultivation and the sustainability of Brazilian agriculture. There is one factor that must be considered when comparing cultivation under organic management to conventional management: the non-use of synthetic chemical inputs, which facilitate production.

“Our objective with this document is not to obtain much higher productivity, but to achieve competitive performance in relation to conventional orchards, based on an organic system, more friendly to the environment and workers”, points out Eduardo Girardi, researcher at Embrapa Mandioca e Fruticultura ( BA), technical editor of the document with researcher Ana Lúcia Borges. The publication brings together a set of technical information on cultivars, seedling production, liming, plastering and fertilization, orchard implementation and planting, cultural treatments, irrigation management, diseases, nematodes and pests, in addition to harvesting, processing, packaging and market. A total of 16 professionals signed the document, including researchers from Embrapa, an agricultural inspector from the Bahia Agricultural Defense Agency (Adab) and a partner from Bioenergia Orgânicos.

The system is another result of the project Development of organic production systems for fruit trees in tropical climates, carried out in partnership since 2011. This joint work has already developed organic production systems for pineapple, passion fruit and mango.

Choosing the Tahiti acid lime

Citrus cultivation was included in the project in 2014. Girardi highlights that two basic precepts are taken into consideration when implementing an organic system: being a region preferably free from the main pests and diseases of the crop and having varieties or species that are more resistant to these phytosanitary threats. And this system combines the two.

“Chapada Diamantina is free from several complex crop pests and diseases, such as HLB huanglongbing (HLB) and citrus canker, caused by bacteria, sudden death and early blight. This makes the work much easier, because implementing organic systems where these diseases exist is much more challenging. Furthermore, among citrus fruits, which also include orange, tangerine, lemon and pomelo, the Tahiti lime is more resistant to some pests and diseases. It is immune, for example, to leprosis, caused by viruses, to brown spot and black spot, caused by fungi and to Citrus Variegated Chlorosis, CVC." It is also less susceptible to citrus canker, therefore, it is a It is a more interesting crop because it is easier to manage. In organic terms, it makes the producer's life much easier, so much so that it is one of the most used fruit plants in this production system in the country.

Bioenergia Orgânicos partner Osvaldo Araújo, one of the authors of the document, adds that, from the moment the decision was made on Tahiti acid lime, a series of precautions were adopted, as it is a climate-sensitive crop and requires specific conditions for good development. Variations in very low or very high temperatures can negatively affect growth and production. “The Chapada Diamantina region tends to experience climate variations, with periods of intense rain and dry periods. It was necessary to implement an adequate irrigation system to supply water in a regular and controlled manner, and it was necessary to monitor soil moisture, as both excess and lack harm the crop cycle”, he adds.

Varieties evaluated

The experiments began in July 2014 and continued until 2021, totaling 1.175 plants, with drip irrigation. Researcher João Roberto Oliveira, who led the activities, says that 16 rootstocks were evaluated – varieties that correspond to the root part of the citrus plant –, mostly new hybrids under development, in combination with the CNPMF-02 clone. This is the crown, the aerial part of the citrus plant), obtained and recommended by Embrapa and widely adopted in Bahia, with a planting spacing of 7,0 meters x 3,0 meters.

“We were able to verify the importance of the rootstock. Because of it, the plant developed differently. Several aspects are analyzed: fruit size, fruit quality in relation to the skin, quantity of fruit per plant, crown development – ​​the smaller the fruit, the easier the harvest –, in short, all of these are very important factors in production, not just limes. acidic, but of any product. And we saw that the rootstocks that stood out the most were the Riverside, Indio and San Diego citrandarins, the Rugoso Maranhão lemon tree, as well as the BRS Victoria and HTR – 010 hybrids”, says Oliveira.

The production system document brings the results of the experiments at Chapada Diamantina and also general data on the most used commercial rootstocks for the Tahiti acid lime tree in the country. The rootstocks must be adapted to the environmental conditions of the region in which they will be used, disease tolerant, and inducers of high productivity and fruit quality. The publication indicates that, as there is no single rootstock capable of completely meeting all these conditions, orchards must be planned in order to diversify the rootstocks, contributing to the sustainability of the crop, and describes the most used in general by the Brazilian citrus industry.

Soil preparation and management

The basis for successful production in an organic system is soil preparation, which must be managed properly, reducing disturbance and maintaining vegetation cover (alive or dead). The publication lists the main requirements of the Tahiti acid lime tree, which adapts well to different soils. The most suitable for cultivation are those with a sandy loam to clay loam texture, with good aeration, deep and without physical obstacles. In Lençóis, the Tahiti acid lime tree has been showing good development under organic production in an irrigated and properly managed area on an oxisol, naturally very poor in nutrients.

Ana Lúcia Borges says that soil preparation began almost two years before the crop was actually introduced. “First we did liming and gypsum based on chemical analysis to correct the soil and then we introduced improving plants, the purpose of which is to condition a good soil structure and increase the organic matter content. We implemented vegetable cocktails made up of legumes, such as jack beans, black mucuna and sunn hemp, and grasses, such as millet and forage sorghum, which have demonstrated excellent vegetative development,” she adds.

According to the researcher, one of the biggest problems with growing organic fruit trees in these nutrient-poor soils is the issue of potassium. “The source of potassium permitted in the organic system, potassium sulfate, obtained through physical procedures, is imported and, therefore, has a high cost. In the document, we point out some low-cost alternatives, such as wood ash and manure and also plant species, such as legumes and grasses. Solutions suitable for small areas, for the family farmer”, she highlights.

The importance of healthy seedlings

The production system recommends that healthy seedlings are essential for the activity to begin with full potential for success. For this reason, only seedlings produced in a protected environment are recommended. The seedlings can be purchased from commercial nurseries or produced in the citrus grower's own nursery, as Bioenergia did.

“The Tahiti acid lime, since the decision to plant this species, has raised concerns for us, as it is a very delicate crop. We had to produce the seedlings internally in a greenhouse with an anti-aphid screen with guidance and supervision from Embrapa researchers”, adds Araújo.

Phytosanitary challenges

The biggest challenge for implementing an organic production system is pest and disease control, given the impossibility of using chemical pesticides. There must be natural vegetation management, nutritional management and constant population monitoring of pests and natural enemies. In the conditions of Lençóis, the first phytosanitary problem the species faced was leaf-cutter ants.

“We tested and validated a product registered with the Ministry of Agriculture and Livestock (Mapa) for organic farming. We spent more than a year testing, mainly adjusting the part of how to apply the granulated bait based on natural Tephrosia candida extract, the raw material for this biological product used to control leaf-cutter ants. And it was a success”, reports researcher Antonio Nascimento.

He says that a saponified syrup was also developed, made up of ethyl alcohol, caustic soda and vegetable oil, which worked well for different pests, not only on the Tahiti acid lime tree but also on other crops. The document provides information on how to prepare the syrup, illustrated with photos. The Tahiti acid lime, for example, is susceptible to orthezia, a species of cochineal that sucks the plant's sap, injects toxins and causes sooty mold to appear on leaves, fruits and branches. The fruits become watery, the plant withers and may even die. The saponified syrup, as highlighted by the researcher, adequately controlled this insect.

The researcher also highlights the importance of constant monitoring in the control of pests and diseases in the organic system. “The issue of applying organic products requires greater frequency. Instead of applying every month, you need to apply every 15 days; in some cases, weekly”, says Nascimento.

Araújo also highlights that keeping the orchard free from pest and disease attacks is the biggest challenge for the development of the crop. “During these years, we managed, with strict control, to keep the orchard free from attacks, however in 2020 a severe attack by some insects began, such as orthezia, aphids and black flies. To overcome the situation, we implemented an integrated control program, involving preventive measures, such as adequate pruning, use of phytosanitary products when necessary and regular monitoring of the orchard.”

The production system provides information on the main pests and diseases of the crop, not only those identified in the Chapada Diamantina region, and their control methods. There is also information on managing nematodes, popularly known as worms. Diseases include those caused by bacteria, fungi and viruses. The document also lists post-harvest diseases and physiological disorders.

Organic agriculture in Brazil

Between 2012 and March 2021, the number of agricultural establishments in the country dedicated to organic production grew by around 300%, reaching 24,7 properties with more than 1 million hectares cultivated, according to data from Mapa. Of the total organic farming properties registered with the Ministry of Agriculture and Livestock, 10% and 25% registered, in 2021, some activity with organic cultivation of other citrus and lemon, respectively.

To be considered organic, the producer must use environmentally sustainable techniques, prohibiting the use of pesticides and soluble chemical fertilizers and must follow the provisions of Law No. 10.831, of December 2003, as well as regulatory instructions and Ordinance 52/ 2021, and be part of Mapa’s National Register of Organic Producers.

There is no official information on the amount of organic production of lemons and acid limes in Brazil. Worldwide, according to 2021 data from the International Federation of Organic Agriculture Movements (Ifoam), approximately 30 thousand hectares of lemons and acid limes are under organic management, which is equivalent to 2,2% of the cultivated area of ​​these crops in the world. Based on this percentage, the estimate, according to Ana Lúcia Borges, is that, in Brazil, around 1,3% of the area of ​​these citrus fruits is cultivated in an organic system, which represents around 760 hectares, and the state of Bahia counts with the largest area.

“Production is still very incipient, but the objective of developing this production system is precisely to contribute to the growth of organic acid lime cultivation in the Chapada Diamantina region and, at the same time, influence other Brazilian regions”, says the researcher who represents Embrapa on the Bahia Organic Production Commission, a forum made up of members from governmental and non-governmental entities.

Acid lime in Brazil and around the world

In the ranking of global production of Tahiti lime, Brazil was, in 2020, the largest producer. However, considering all acidic citrus fruits (limes and lemons), it occupied fifth position, accounting for 7,42% of world production, with 1.585.215 tons in 58.438 hectares harvested, according to 2020 data from the United Nations for Food and Agriculture (FAO).

In 2021, the main producing states were São Paulo, Minas Gerais, Pará and Bahia, according to the Brazilian Institute of Geography and Statistics (IBGE). In São Paulo alone, production was 1.073.437 tons, in 32.564 hectares harvested, with the Tahiti acid lime accounting for around 90% of the area cultivated with acid citrus fruits in that state, according to the Citrus Defense Fund (Fundecitrus ). It ranks fourth in exports among Brazilian fresh fruits, behind only mango, melon and grapes, according to 2019 data available on the Comex platform.