A whole system approach
Many organic farms involve a mix of crops that may include mangoes, bananas, citrus or other fruits and possibly some seasonal vegetables. Production of mangoes must be considered as only one component of an integrated whole farm system.
The inclusion of other crops from unrelated botanical families, as well as soil regenerating pasture or green manure phases, and the use of other plant species can have implications for management of pests, diseases or weeds.
The whole system is designed and managed to optimise benefits and minimise problems across all crops arising from treatments to any one crop. The layout of cropped areas may change towards more mixed cropping as a way of breaking up large areas of a single crop, thereby increasing biodiversity and assisting pest and disease management.
Enterprises aim to become closed systems
Organic farms aim to operate as closed systems wherever possible - using renewable resources, maximising recycling, minimising waste and reducing reliance on outside (off-farm) inputs as far as practical.
Management strategies based on an understanding of biological cycles and other interactions are the main tools that replace reliance on synthetic chemical and non-renewable inputs.
Organic farms can be managerially more complex, but should be less dependent on the use of external inputs.
Plant health stems from soil health
The underlying principle of organic crop production is that: ‘healthy plants grow from healthy soil’. Well balanced, biologically enhanced soil - measured by adequate organic matter, humus level, crumb structure and feeder root development - forms the basis of organic production. Plants are nourished through an ecosystem built over time, and not primarily through fast-acting, soluble fertilisers added to the soil.
Synthetic fertilisers and chemical pesticides and herbicides are not permitted and can be detrimental to biologically active healthy soil.
Conservation and recycling of nutrients is a major feature of any organic farming system. Organic and mineral fertilisers should be used as a supplement to recycling, not as a replacement.
Land degradation problems such as organic matter depletion, soil structure decline, compaction, erosion, and nutrient leaching must be avoided. In general, well managed soils with adequate organic matter, biological activity and humus formation tend to be more resilient against most forms of land degradation.
Biological processes are important
Organic systems are primarily biological systems, both above and below the soil. Pest, disease and weed control must encourage and maintain natural biological processes so as to balance disease and pest problems. Enhancement and manipulation of these biological processes forms the basis of organic management. Other control measures can include:
- choice of crop species and varieties for resistance
- orchard layout and tree structure and canopy management
- orchard hygiene
- orchard floor species mix
- mulching and mowing regimes
- biological control and maintenance of beneficial predator habitats
- mechanical controls such as traps, barriers, light, sound and pheromones.
Where available, the grower should use organically grown nursery plants, not treated with synthetic chemicals.
Growers may initially convert part of a property to organic methods while continuing to use conventional methods on the remainder. Sometimes referred to as parallel production, this typically involves selecting a location with low risk of spray drift or contamination from adjacent land. Buffer zones may be required to ensure adequate separation from conventional cropping.
Where the same variety is grown both organically and conventionally on the same property, the grower must demonstrate that very tight management protocols for product separation and record keeping are in place to allow complete verification of production volumes and trace-back through the operation.
Sufficient area must be allocated to develop a proper functioning organic system. Some organic certifiers may also require a development plan that aims to convert the whole property to an organic system within a defined period. Moving into and out of organic certification is generally unacceptable.
Minimum qualifying period
The transition from a conventional system to a balanced, biologically active organic system is a gradual process. For organic mango production the land must be managed in accordance with organic standards for a minimum of three years.
However, growers can obtain certification as ‘in conversion’ to organic after completion of one year (pre-certification) of compliance with organic standards. Markets for ‘in conversion’ status fruit may require careful assessment as premiums can be lower than for full ‘organic’ certification. Product in the first year of conversion (pre-certification) cannot be sold and labelled as organic.
Contamination and spray drift
Potential sources of contamination, from spray drift, water or other means, can require careful consideration. Buffer zones are likely to be required between organic crops and conventional crops. Neighbours must be informed of contamination risk and co-operation sought. Soil tests may be required to check for chemical residues in soil from previous land use.
Old orchard sites can potentially have residual soil contamination from past use of synthetic chemicals such as DDT or dieldrin. Generally soil chemical residues should be less than 10% of the MRL (maximum residue limit). Where soil residue is above this level, special orchard management and tissue testing conditions can apply.
Genetic engineering banned
The use of genetically engineered (GE) organisms and their products is prohibited in any form or at any stage in organic production, processing or handling. Crops and land must be free of GE contamination. Land must have at least five years freedom from previous GE crops.
Co-existence with and protection of the environment
Maintaining biological diversity on and around the farm is an important feature of organic systems. Avoiding monocultures by encouraging biological diversity tends to allow ecological balance or equilibrium to establish, resulting in a more stable system with less dramatic biological fluctuations - both on the farm and in the surrounding natural environment.
Areas of remnant vegetation should be protected. Shelterbelts and areas of remnant vegetation can be important habitat for natural predators of insect pests, which when kept naturally in check reduce harm to crops and reduce the need for control measures.
Organic farms should also ensure that pollution and other forms of degradation resulting from agricultural practices are avoided. The use of non-renewable resources should also be minimised to help extend future availability of these finite resources.
Irrigation must be adequately managed, scheduled and monitored to reduce problems with watertable, leaching of nutrients and salinity inducement. Irrigation management must minimise disturbance to the environment and natural ecosystems, including wetlands, river flow regimes and wildlife habitat.
Postharvest, storage and processed products
To prevent contamination of mangoes on the farm, organic product must be kept in a dedicated storage area separate from conventional product. Postharvest treatments and packaging materials must comply with organic standards.
Where growers intend to value add or process mangoes, compliance with organic processing standards is required if the final product is to be labelled as certified “Organic”.