Culture in field conditions - Challenges A South American point of view Roberto Campos Pura Natura, Argentina

Transcription

1 A South American point of view Roberto Campos Pura Natura, Argentina EUSTAS 6 th Stevia Symposium Leuven, July 3 rd and 4 th

2 I. Area of cultivation II. Environment III. Production of seedlings IV. Planting V. Maintenance of the field VI. Harvesting VII. Drying VIII. Cost control IX. Conclusion

3 I. Area of cultivation Less than 5 hectares Traditional form Normally run by a family with own handcraft - still the most important resource of Stevia leaves Strong dependance on Stevia leaves buyers (demand) Difference to horticulture: perennial plant

4 I. Area of cultivation 5 20 hectares It can be an association of small farmers, one individual or a small company Needs implementation of basic mechanisation More people involved Own seedlings production or done in a pool 20 hectares and above This can be done by cooperativas (temporary farmer associations), big companies seeking a secure and traceable supply of leaves Mechanisation is necessary Logistics become important

5 II. Environment First crossroad: a) The land is set => find the adequate stevia variety b) An excellent variety is available => find the best agricultural conditions A prolongued period of experimenting will be needed until the ideal adaptation between variety and environment is found.

6 II. Environment Climate Temperature: ideal range is from 15 to 30 C Water requirements: about 1800 mm yearly Microclimates: A height differences of 200m in the same region can result in considerable variations in climatic behaviour. Moderate climates throughout the year will give you the best performance (8 tons/year). The right combination of sunlight, temperature and water will determinate the quality and quantity of the steviolglycosides production.

7 II. Environment Soil The chemical and physical conditions of the soil are important. The bigger the area, the straighter the ground has to be. Big areas need mechanisation, which means a firm underground to sustain the machines in rainy seasons. A good underground is a sandy soil. Rain characteristics combined with ground configuration will decide how to design the field to avoid washing out the soil or to preserve the water. Avoid a terrain prone to puddles.

8 II. Environment Irrigation Irrigation is to be considered as complementary to rain. Since rainfall can't be guaranteed, irrigation is needed in the critical periods such as the implantation period, after harvest and during high temperature peaks. The three most common types of irrigation are: By pivots, if you have plenty of water With sprinklers, in a relatively small area By dripping, if water quantity is a problem An adequate water supply will avoid stress in the plants, which will result in less diseases and better biomass production.

9 II. Environment Irrigation Pivots frontal and circular

10 II. Environment Irrigation Sprinklers Dripping

11 III. Production of seedlings Calendar window for planting the seedlings depends on the climate. Timely planning is crucial. Types of seedlings: Clones - more homogeneous plantation since all the plants will have the same chemical composition and exactly the same biological behaviour. Seminal multiplication - stronger plants, better resistance against diseases, more efficiency in the absorption of water and nutrients once they are on the field. Also a longer productive time if submitted to harvesting. If cost of seedlings is an important factor, seminal propagation is the way to go.

12 III. Production of seedlings The right training of the greenhouse personnel is in direct relationship to the quality and quantity of seedlings production as cleanliness, humidity conditions and temperature control are factors that need a tight supervision. Cuttings Clones Trays

13 III. Production of seedlings By seeds Greenhouse Watering is critical - quantity and quality

14 III. Production of seedlings Adaptation period

15 IV. Planting The geographical location will determine the months of the year in which the seedlings can be brought to the field. There are two alternatives for planting the seedling: with bare root or coming from a tray with the corresponding rootball.

16 IV. Planting A comparison between manual and mechanised planting shows that 18 people with appropriate tools are needed to plant 1 ha. of plants in one day.

17 IV. Planting If done with a machine, 3 4 people are needed to achieve 1 ha. a day. With rootball Naked root

18 IV. Planting The density of plants and the distribution will be given by: Variety of the plant Planting and harvesting characteristics Irrigation system Usually the planting density varies from to plants per hectare.

19 IV. Planting Plant variety

20 V. Maintenance of the field Throughout the year an intensive maintenance is needed - it comprises: Irrigation (throughout the year) Fertilization (periodically) Application of herbicides and insecticides (regular applications) Mechanical and manual weeding (throughout the year) Uniform height cuttings (before spring) Plant reposition (end of winter period) Special care has to be taken with the emergence of diseases, mainly fungal and also insect attacks. One has to react immediately to these threats.

21 V. Maintenance of the field Diseases Fungi: such as Sclerotinia basal stalk rot, Septoria leaf rot, Alternaria, Oidium, Fusarium stalk rot, Rhizopus head rot and Phytophotora stem rot. Insects: there is a small spider, cicadas, nematodes and acari.

22 V. Maintenance of the field Fighting diseases & weeds Weeds, insects and diseases are characteristic of each specific region so a solution has to be found locally. Usually one can lean on the treatments for horticulture. In Brazil for example, it is allowed to apply the agrochemicals registered for minor crops for stevia plantations. Consider that different stevia varieties show a different behaviour when facing specific diseases. Well trained people have to walk through the field regularily to check for diseases.

23 V. Maintenance of the field ideal development

24 VI. Harvesting Timing: ideally when it begins to bloom. (stevioglycosides content in the leaves at its highest) Frequency: depending on climate harvesting can occur 1-8 times a year Quantity: 1,5 to 8 tons of dried leaves per hectare per year (depending on plant density)

25 VI. Harvesting Harvesting machines will be needed for plantations over 10 hectares. The layout of the planting area will be dependant on how you will harvest.

26 VII. Drying Immediately after harvesting the appropriate drying procedure has to be started to guarantee a good dry leaves quality. Drying in the sun is appropriate for sunny regions. It is cost efficient. Wide, clean surfaces are needed and any rainfall whatsoever must be avoided. This is the most manpower intensive step, including the following separation of the leaves from the stems. Very big drying equipment exists, but due to the energy necessary to dry the plants until they have less than 10% humidity the resulting drying costs are very high.

27 VIII. Cost control Cost influencers: high manpower involved in seedling production, weeding the field and drying and packaging elevated water consumption energy needed for drying and the investment in greenhouses, irrigation and mechanisation

28 IX. Conclusions The critical steps in the stevia production on the field are: Plant genetics and their adaptation to the environment (climate, diseases) will define the quality and quantity of leaves production Manpower resources and their training is a critical issue Irrigation is needed to guarantee a good biomass production Weeds and diseases control is the biggest challenge you will face Harvesting and drying are the bottlenecks you will have to solve Costs - if you want to keep them as low as possible you have to design ideal logistics to optimize the use of your resources

29 Thank you for your attention! Any questions?